Comprehensive Nuclear-Test-Ban Treaty:
Background and Current Developments

Jonathan E. Medalia
Specialist in Nuclear Weapons Policy
June 2, 2015
Congressional Research Service
7-5700
www.crs.gov
RL33548


Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

Summary
A ban on all nuclear tests is the oldest item on the nuclear arms control agenda. Three treaties that
entered into force between 1963 and 1990 limit, but do not ban, such tests. In 1996, the United
Nations General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which
would ban all nuclear explosions. In 1997, President Clinton sent the CTBT to the Senate, which
rejected it in October 1999. In a speech in Prague in April 2009, President Obama said, “My
administration will immediately and aggressively pursue U.S. ratification of the Comprehensive
Test Ban Treaty.” However, while the Administration has indicated it wants to begin a CTBT
“education” campaign with a goal of securing Senate advice and consent to ratification, it has not
pressed for a vote on the treaty and there were no hearings on it in the 111th, 112th, or 113th
Congresses, or so far in the 114th.
As of June 2015, 183 states had signed the CTBT and 164, including Russia, had ratified it.
However, entry into force requires ratification by 44 states specified in the treaty, of which 41 had
signed the treaty and 36 had ratified. Eight conferences have been held to facilitate entry into
force, every other year, most recently on September 27, 2013. In years between these
conferences, some foreign ministers meet to promote entry into force of the CTBT; the most
recent was held on September 26, 2014.
Nuclear testing has a long history, beginning in 1945. The Natural Resources Defense Council
states that the United States conducted 1,030 nuclear tests, the Soviet Union 715, the United
Kingdom 45, France 210, and China 45. (Of the U.K. tests, 24 were held jointly with the United
States and are not included in the foregoing U.S. total.) The last U.S. test was held in 1992;
Russia claims it has not tested since 1990. In 1998, India and Pakistan announced several nuclear
tests. Each declared a test moratorium; neither has signed the CTBT. North Korea announced that
it conducted nuclear tests in 2006, 2009, and 2013. Since 1997, the United States has held 28
“subcritical experiments” at the Nevada National Security Site, most recently in August 2014, to
study how plutonium behaves under pressures generated by explosives. It asserts these
experiments do not violate the CTBT because they cannot produce a self-sustaining chain
reaction. Russia reportedly held some such experiments since 1998.
The Stockpile Stewardship Program seeks to maintain confidence in the safety, security, and
reliability of U.S. nuclear weapons without nuclear testing. Its budget is listed as “Weapons
Activities” within the request of the National Nuclear Security Administration, a semiautonomous
component of the Department of Energy. Congress addresses nuclear weapon issues in the annual
National Defense Authorization Act and the Energy and Water Development Appropriations Act.
The FY2016 request for Weapons Activities was $8.846.9 million; on a comparable basis, the
FY2014 current amount was $7,625.7 million and the FY2015 enacted amount was $8,007.7
million. Congress also considers a U.S. contribution to a global system to monitor possible
nuclear tests, operated by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban
Treaty Organization. The FY2016 request for the contribution was $33.0 million.
This report will be updated occasionally. This update reflects the FY2016 budget request and
developments through May 2015. CRS Report RL34394, Comprehensive Nuclear-Test-Ban
Treaty: Issues and Arguments
, by Jonathan E. Medalia, presents pros and cons in detail. CRS
Report R40612, Comprehensive Nuclear-Test-Ban Treaty: Updated “Safeguards” and Net
Assessments
, by Jonathan E. Medalia, discusses safeguards—unilateral steps to maintain U.S.
nuclear security consistent with nuclear testing treaties—and their relationship to the CTBT. CRS
Congressional Research Service

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

Report R43948, Energy and Water Development: FY2016 Appropriations for Nuclear Weapons
Stockpile Stewardship
, by Jonathan E. Medalia, provides details on stockpile stewardship.

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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

Contents
Most Recent Developments ............................................................................................................. 1
History ............................................................................................................................................. 1
National Positions on Testing and the CTBT................................................................................... 2
The North Korean Nuclear Tests ................................................................................................... 13
The October 2006 Nuclear Test ............................................................................................... 13
The May 2009 Nuclear Test .................................................................................................... 16
A Test in May 2010? ................................................................................................................ 17
The February 2013 Nuclear Test ............................................................................................. 18
CTBT Negotiations, Provisions, Entry into Force ......................................................................... 21
CTBT Negotiations and the Nuclear Nonproliferation Treaty ................................................ 21
Key Provisions of the CTBT ................................................................................................... 25
International Efforts on Behalf of Entry into Force ................................................................. 30
Budget of the CTBTO Preparatory Commission ........................................................................... 35
Stockpile Stewardship .................................................................................................................... 37
Stockpile Stewardship and the CTBT ...................................................................................... 38
Stockpile Stewardship Experiments and Facilities .................................................................. 46
Subcritical Experiments .................................................................................................... 46
Other Experiments and Experimental Facilities ................................................................ 47
Nuclear Test Readiness ............................................................................................................ 49
CTBT Pros and Cons ..................................................................................................................... 52
The National Academy of Sciences Study and Its Critics ....................................................... 53
Chronology .................................................................................................................................... 55
For Additional Reading .................................................................................................................. 58

Tables
Table 1. Projected Budgets for Weapons Activities, FY2016-FY2020 ($ billions) ....................... 45
Table 2. U.S. Nuclear Tests by Calendar Year ............................................................................... 52

Appendixes
Appendix. Chronology, 1992-2009 ............................................................................................... 66

Contacts
Author Contact Information........................................................................................................... 74

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Most Recent Developments
The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization
(CTBTO PrepCom) will hold its 2015 Science and Technology Conference from June 22 to 26,
2015, in Vienna, Austria. It is “designed to further enhance the strong relationship between the
scientific and technological community and the CTBTO.” The 2015 Review Conference on the
Nuclear Non-Proliferation Treaty was held from April 27 to May 22 in New York. At the
conference, over 100 states expressed support for the Comprehensive Nuclear-Test-Ban Treaty
(CTBT). On May 12-14, 2015, the CTBTO PrepCom and others held a Workshop on Signatures
of Medical and Industrial Isotope Production. Certain radioactive materials have great medical
value, but their production may release radioactive xenon, which is also a signature of nuclear
tests. The workshop “explore[d] ways to mitigate the effects on nuclear explosion monitoring of
emissions from facilities that produce lifesaving medical isotopes without impacting production.”
On March 20, 2015, Angola became the 164th state to ratify the CTBT. On February 24, 2015, the
CTBTO PrepCom and Ecuador concluded an agreement to build two stations of the International
Monitoring System on the Galapagos Islands. The Vienna Conference on the Humanitarian
Impact of Nuclear Weapons was held December 8 and 9, 2014, in Vienna, Austria. The final
report stated, “A number of delegations argued that a step-by-step approach was the most
effective and practical way to achieve nuclear disarmament, referring in particular to the entry
into force of the CTBT and a Treaty banning the production of fissile material for nuclear
weapons.” The CTBTO PrepCom conducted IFE14 (Integrated Field Exercise 2014) in Jordan
from November 3 to December 9, 2014, to simulate an on-site inspection to detect a clandestine
nuclear test.
History
While the CTBT was opened for signature in 1996,1 it has not entered into force, leaving a ban on
nuclear testing as the oldest item on the arms control agenda. Efforts to curtail tests have been
made since the 1940s. In the 1950s, the United States and Soviet Union conducted hundreds of
hydrogen bomb tests. The radioactive fallout from these tests spurred worldwide protest. These
pressures, plus a desire to improve U.S.-Soviet relations in the wake of the Cuban Missile Crisis
of 1962, led to the Limited Test Ban Treaty of 1963, which banned nuclear explosions in the
atmosphere, in space, and under water. The Threshold Test Ban Treaty, signed in 1974, banned
underground nuclear weapons tests having an explosive force of more than 150 kilotons, the
equivalent of 150,000 tons of TNT, 10 times the force of the Hiroshima bomb. The Peaceful
Nuclear Explosions Treaty, signed in 1976, extended the 150-kiloton limit to nuclear explosions
for peaceful purposes. President Carter did not pursue ratification of these treaties, preferring to
negotiate a comprehensive test ban treaty, or CTBT, a ban on all nuclear explosions. When
agreement on a CTBT seemed near, however, he pulled back, bowing to arguments that continued
testing was needed to maintain reliability of existing weapons, to develop new weapons, and for
other purposes. President Reagan raised concerns about U.S. ability to monitor the two unratified

1 For treaty text and analysis, see U.S. Congress. Senate. Comprehensive Nuclear Test-Ban Treaty: Message from the
President of the United States Transmitting Comprehensive Nuclear Test-Ban Treaty ... ,
Treaty Doc. 105-28,
September 23, 1997. Washington: GPO, 1997, xvi + 230 p, http://www.gpo.gov/fdsys/pkg/CDOC-105tdoc28/pdf/
CDOC-105tdoc28.pdf, and U.S. Department of State. “Comprehensive Test Ban Treaty (CTBT),”
http://www.state.gov/t/isn/trty/16411.htm.
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treaties and late in his term started negotiations on new verification protocols. These two treaties
were ratified in 1990.
With the end of the Cold War, the need for improved warheads dropped and pressures for a CTBT
grew. The U.S.S.R. and France began nuclear test moratoria in October 1990 and April 1992,
respectively. In early 1992, many in Congress favored a one-year test moratorium. The effort led
to the Hatfield-Exon-Mitchell amendment to the FY1993 Energy and Water Development
Appropriations Bill, which banned testing before July 1, 1993, set conditions on a resumption of
testing, banned testing after September 1996 unless another nation tested, and required the
President to report to Congress annually on a plan to achieve a CTBT by September 30, 1996.
President George H. W. Bush signed the bill into law (P.L. 102-377) October 2, 1992. The CTBT
was negotiated in the Conference on Disarmament. It was adopted by the U.N. General Assembly
on September 10, 1996, and was opened for signature on September 24, 1996. As of June 2015,
183 states had signed it and 164 had ratified.2
National Positions on Testing and the CTBT
United States: As of June 2015, the United States had signed but not ratified the CTBT. The
following history casts light on the U.S. position.
Under the Hatfield-Exon-Mitchell amendment, President Clinton had to decide whether to ask
Congress to resume testing. On July 3, 1993, he said, “A test ban can strengthen our efforts
worldwide to halt the spread of nuclear technology in weapons,” and “the nuclear weapons in the
United States arsenal are safe and reliable.” While testing offered advantages for safety,
reliability, and test ban readiness, “the price we would pay in conducting those tests now by
undercutting our own nonproliferation goals and ensuring that other nations would resume testing
outweighs these benefits.” Therefore, he (1) extended the moratorium at least through September
1994; (2) called on other nations to extend their moratoria; (3) said he would direct DOE to
“prepare to conduct additional tests while seeking approval to do so from Congress” if another
nation tested; (4) promised to “explore other means of maintaining our confidence in the safety,
the reliability and the performance of our own weapons”; and (5) pledged to refocus the nuclear
weapons laboratories toward technology for nuclear nonproliferation and arms control
verification. He extended the moratorium twice more; on January 30, 1995, the Administration
announced his decision to extend the moratorium until a CTBT entered into force, assuming it
was signed by September 30, 1996.
On September 22, 1997, President Clinton submitted the CTBT to the Senate. He asked the
Senate to approve it in his State of the Union addresses of 1998 and 1999. Senate Foreign
Relations Committee Chairman Helms rejected that request, saying that the treaty “from a non-
proliferation standpoint, is scarcely more than a sham” and had low priority for the committee. In
summer 1999, Senate Democrats pressed Senators Helms and Lott to permit consideration of the
treaty. On September 30, 1999, Senator Lott offered a unanimous-consent request to discharge the
Senate Foreign Relations Committee from considering the treaty and to have debate and a vote.
The request, as modified, was agreed to. The Senate Armed Services Committee held hearings
October 5-7; the Foreign Relations Committee held a hearing October 7. It quickly became clear

2 For a current list of signatures and ratifications, see “Status of Signature and Ratification” at the Comprehensive
Nuclear Test-Ban-Treaty Organization website, http://www.ctbto.org/the-treaty/status-of-signature-and-ratification/.
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that the treaty was far short of the votes for approval, leading many on both sides to seek to delay
a vote. As the vote was scheduled by unanimous consent, and several Senators opposed a delay,
the vote was held October 13, rejecting the treaty, 48 for, 51 against, and 1 present. At the end of
the 106th Congress, pursuant to Senate Rule XXX, paragraph 2, the treaty moved to the Senate
Foreign Relations Committee calendar, where it currently resides.
The Bush Administration’s Nuclear Posture Review and Nuclear Testing: In the FY2001
National Defense Authorization Act (P.L. 106-398, §1041), Congress directed the Secretary of
Defense, in consultation with the Secretary of Energy, to review nuclear policy, strategy, arms
control objectives, and the forces, stockpile, and nuclear weapons complex needed to implement
U.S. strategy. Although the resulting Nuclear Posture Review is classified, J.D. Crouch, Assistant
Secretary of Defense for International Security Policy, presented an unclassified briefing on it on
January 9, 2002, dealing in part with the CTBT and nuclear testing.3 He stated there would be “no
change in the Administration’s policy at this point on nuclear testing. We continue to oppose
CTBT ratification. We also continue to adhere to a testing moratorium.” Further, “DOE is
planning on accelerating its test-readiness program” to reduce the time needed between a decision
to test and the conduct of a test, which was then 24 to 36 months. He discussed new weapons. “At
this point, there are no recommendations in the report about developing new nuclear weapons ...
we are trying to look at a number of initiatives. One would be to modify an existing weapon, to
give it greater capability against ... hard targets and deeply-buried targets. And we’re also looking
at non-nuclear ways that we might be able to deal with those problems.” A Washington Post
article of January 10, 2002, quoted White House Press Secretary Ari Fleischer as saying that the
President has not ruled out testing “to make sure the stockpile, particularly as it is reduced, is
reliable and safe. So he has not ruled out testing in the future, but there are no plans to do so.”4
Critics expressed concern about the implications of these policies for testing and new weapons.
Physicians for Social Responsibility argued, “The Administration’s plan ... would streamline our
nuclear arsenal into a war-fighting force, seek the opportunity to design and build new nuclear
weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”5 Another critic
felt that increased funding for test readiness would in effect give prior approval for testing.
In July 2002 a National Academy of Sciences panel report on technical aspects of the CTBT
concluded, in the words of a press release, “that verification capabilities for the treaty are better
than generally supposed, U.S. adversaries could not significantly advance their nuclear weapons
capabilities through tests below the threshold of detection, and the United States has the technical
capabilities to maintain confidence in the safety and reliability of its existing weapons stockpile
without periodic nuclear tests.”6
A U.N. draft document of August 5, 2005, for signature by heads of government and heads of
state at the U.N. General Assembly meeting of September 2005, contained a provision that the
signers “resolve to ... [m]aintain a moratorium on nuclear test explosions pending the entry into

3 U.S. Department of Defense. News Transcript: “Special Briefing on the Nuclear Posture Review,” January 9, 2002;
see http://www.defenselink.mil/transcripts/2002/t01092002_t0109npr.html.
4 Walter Pincus, “U.S. Aims for 3,800 Nuclear Warheads,” Washington Post, January 10, 2002.
5 Physicians for Social Responsibility, “PSR: Bush Nuclear Weapons Plan Sets Stage for new Bombs, Resumption of
Testing; Plan Endangers National Security, Public Health,” press release via U.S. Newswire, January 8, 2002.
6 The National Academies, “Academy Addresses Technical Issues in Nuclear Test Ban Treaty ...,” press release, July
31, 2002. The full report, Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty, is available at
http://www.nap.edu/catalog.php?record_id=10471#toc.
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force of the Comprehensive Nuclear-Test-Ban Treaty and call upon all States to sign and ratify
the Treaty.”7 John Bolton, the U.S. Ambassador to the United Nations, reportedly called for major
changes to the draft; the CTBT passage was one of many drawing his objection.8
On June 25, 2007, Secretary of State Condoleezza Rice stated:
the Administration does not support the Comprehensive Test Ban Treaty and does not intend
to seek Senate advice and consent to its ratification. There has been no change in the
Administration’s policy on this matter. By reducing the likelihood of the need to return to
underground nuclear testing, RRW [the Reliable Replacement Warhead] makes it more
likely that the United States would be able to continue its voluntary nuclear testing
moratorium. We cannot, however, provide guarantees regarding the voluntary moratorium.
We may find at some future time that we cannot diagnose or remedy a problem in a warhead
critical the U.S. nuclear deterrent without conducting a nuclear test.9
Similarly, a Statement of Administration Policy on S. 1547, FY2008 National Defense
Authorization Act, included the following:
While supporting the continued voluntary moratorium on testing, the Administration
strongly opposes a provision of section 3122 that calls for the ratification of the CTBT. It
would be imprudent to tie the hands of a future administration that may have to conduct a
test of an element of an aging, unmodernized stockpile in order to assure the reliability of the
nuclear deterrent force. Absent such a test, the United States may not be able to diagnose or
remedy a problem in a warhead critical to the Nation’s deterrent strategy.10
The Obama Administration and the CTBT: In a speech in Prague on April 5, 2009, President
Obama said, “my administration will immediately and aggressively pursue U.S. ratification of the
Comprehensive Test Ban Treaty.”11 Secretary of State Hillary Clinton stated, “The
Comprehensive Nuclear-Test-Ban Treaty is an integral part of our non-proliferation and arms
control agenda, and we will work in the months ahead both to seek the advice and consent of the
United States Senate to ratify the treaty, and to secure ratification by others so that the treaty can
enter into force.”12 Secretary of Defense Robert Gates, asked if the United States should ratify the
CTBT, replied, “I think that if there are adequate verification measures, probably should.”13
The Obama Administration released its Nuclear Posture Review (NPR) report in April 2010,
which “focuses on five key objectives of our nuclear weapons policies and posture:

7 U.N. General Assembly. “Revised draft outcome document of the High-level Plenary Meeting of the General
Assembly of September 2005 submitted by the President of the General Assembly,” A/59/HLPM/CRP.1/Rev.2,
advance unedited version, August 5, 2005.
8 Julian Borger, “Question Mark over the Summit,” Manila Bulletin, August 27, 2005.
9 Letter from Condoleezza Rice, Secretary of State, to Honorable Pete Domenici, United States Senate, June 25, 2007.
10 U.S. Executive Office of the President. Office of Management and Budget. “Statement of Administration Policy: S.
1547—National Defense Authorization Act for Fiscal Year 2008,” p. 7, at http://www.whitehouse.gov/omb/legislative/
sap/110-1/s1547sap-s.pdf.
11 U.S. White House. Office of the Press Secretary. “Remarks by President Obama,” Hradcany Square, Prague, Czech
Republic, April 5, 2009, http://www.whitehouse.gov/the_press_office/Remarks-By-President-Barack-Obama-In-
Prague-As-Delivered/.
12 “Secretary of State Hillary Rodham Clinton, Remarks at CTBT Article XIV Conference, New York, NY, September
24, 2009,” p. 2, http://www.ctbto.org/fileadmin/user_upload/Art_14_2009/240909_Morning_Session/240909_US.pdf.
13 Robert Gates, “Nuclear Weapons and Deterrence in the 21st Century,” address to the Carnegie Endowment for
International Peace, Washington, DC, October 28, 2008.
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1. Preventing nuclear proliferation and nuclear terrorism;
2. Reducing the role of U.S. nuclear weapons in U.S. national security strategy;
3. Maintaining strategic deterrence and stability at reduced nuclear force levels;
4. Strengthening regional deterrence and reassuring U.S. allies and partners; and
5. Sustaining a safe, secure, and effective nuclear arsenal.”14
Consistent with Administration statements, the report presented the CTBT as a way to implement
the first objective. It called several arms control measures, including the CTBT, “a means of
strengthening our ability to mobilize broad international support for the measures needed to
reinforce the non-proliferation regime and secure nuclear materials worldwide.”15 It viewed
ratification and early entry into force of the CTBT as contributing to the prevention of nuclear
proliferation and nuclear terrorism:
Ratification of the CTBT is central to leading other nuclear weapons states toward a world of
diminished reliance on nuclear weapons, reduced nuclear competition, and eventual nuclear
disarmament. U.S. ratification could also encourage ratification by other states, including
China, and provide incentives for the remaining states to work toward entry into force of the
treaty. Further, U.S. ratification of the CTBT would enable us to encourage non-NPT Parties
to follow the lead of the NPT-recognized Nuclear Weapon States in formalizing a heretofore
voluntary testing moratorium, and thus strengthen strategic stability by reducing the salience
of nuclear weapons in those states’ national defense strategies.16
The report also called for a substantial effort to maintain nuclear weapons and to upgrade the
workforce and physical infrastructure of the nuclear weapons complex.
Vice President Joseph Biden wrote, “The President has made ratification of the Comprehensive
Test Ban Treaty an Administration priority. He has asked me to guide the Administration’s effort
to gain Senate support for the treaty.”17 Under Secretary of State Ellen Tauscher described
elements of the Administration’s strategy to win Senate approval of the treaty. “This
administration will not attempt to [seek ratification] unless we believe it can actually pass.... [We
are] laying the groundwork for the support of a supermajority in the Senate, 67 votes.... We [will]
have a very, very short window to talk about CTBT. But when we believe that we have the right
conditions, we will begin to engage the Senate.”18
Obtaining Senate advice and consent to ratification has proven to be a challenge. Senator John
Kerry, then chairman of the Senate Foreign Relations Committee, stated, “I will begin working to
build the necessary bipartisan support for U.S. ratification of the Comprehensive Nuclear Test
Ban Treaty ... success would be the single greatest arms control accomplishment for the new

14 U.S. Department of Defense. Nuclear Posture Review Report. April 2010, p. iii, http://www.defense.gov/npr/docs/
2010%20Nuclear%20Posture%20Review%20Report.pdf.
15 Ibid., p. vii.
16 Ibid., p. 13.
17 Letter from Vice President Joseph R. Biden, Jr., to The Honorable Edward Pastor, Chairman, Subcommittee on
Energy and Water Development, Committee on Appropriations, House of Representatives, September 16, 2009.
18 “Pressing a Broad Agenda for Combating Nuclear Dangers: An Interview with Undersecretary of State for Arms
Control and International Security Ellen Tauscher,” interviewed by Daniel Horner and Tom Collina, Arms Control
Today,
November 2009, pp. 8-9. Brackets in the quote are from the text of the article.
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Senate and it would reestablish America’s traditional leadership role on nonproliferation.”19 On
the other hand, Senate Minority Leader Mitch McConnell said, “I also disagree with the
administration’s recent pledge to ratify the Comprehensive Test Ban Treaty.”20
The timeline for Senate consideration of the CTBT is uncertain. The Administration decided to
press for Senate approval of the U.S.-Russian New Strategic Arms Reduction Treaty (New
START) before trying to bring up the CTBT. However, New START fell behind schedule. The
treaty it replaced, the Strategic Arms Reduction Treaty (START), expired in December 2009.
President Obama signed the new treaty in April 2010 and submitted it to the Senate in May. The
Senate Committees on Armed Services, Foreign Relations, and Intelligence held hearings on New
START, and the Foreign Relations Committee reported it favorably.21 President Obama reportedly
made securing Senate advice and consent to ratification of New START one of his top priorities
for the lame duck session of Congress.22 The Senate passed the resolution of ratification for that
treaty on December 22, 2010, 71-26. Subsequently, Administration officials turned more attention
to the CTBT. For example, on September 23, 2011, Ellen Tauscher, then Under Secretary of State
for Arms Control and International Security, said, “we have begun the process of engaging the
Senate. We like to think of our efforts as an ‘information exchange’ and are working to get these
facts [on verification and stockpile stewardship capabilities] out to members and staff, many of
whom have never dealt with this Treaty.”23 On September 26, 2012, Rose Gottemoeller, Acting
Under Secretary of State for Arms Control and International Security, said, “As we look towards
ratification of the CTBT, we acknowledge that the process will not be easy. That said, the New
START ratification process reinvigorated interest in the topic of nuclear weapons and arms
control on Capitol Hill. I am optimistic that interest will continue as we engage with Members
and staff on this Treaty.”24 On September 15, 2014, Gottemoeller, who had been confirmed as
Under Secretary of State for Arms Control and International Security, said,
Now, I will pivot to the question that is asked each and every time this Treaty is discussed:
“What is the plan for Senate ratification?”
The answer is simple. First comes education, and then comes discussion and last and most
importantly, comes debate. It is only through that process that you get to a place where a
vote could happen.
We are reintroducing this Treaty to the American public, since it has been quite some time it
has been discussed outside the Capital Beltway. We are and will continue to outline the clear
and convincing facts about our ability to maintain the nuclear stockpile without explosive
testing and our ability to effectively monitor and verify Treaty compliance. Both Secretary

19 John Kerry, “New Directions for Foreign Relations,” Boston Globe, January 13, 2009.
20 Senator Mitch McConnell, “U.S. Foreign Policy,” remarks in the Senate, Congressional Record, daily edition, April
27, 2009, p. S4727.
21 Links to the hearings are available at U.S. Department of State. Bureau of Arms Control, Verification and
Compliance. “Senate Hearings for New START,” http://www.state.gov/t/avc/rls/c38598.htm. The Senate Foreign
Relations Committee’s report is available at http://www.gpo.gov/fdsys/pkg/CRPT-111erpt6/pdf/CRPT-111erpt6.pdf.
22 Mary Beth Sheridan and Walter Pincus, “Sources: $4 Billion Bid to Save START,” Washington Post, November 13,
2010, p. 3.
23 U.S. Department of State. Ellen Tauscher, Under Secretary for Arms Control and International Security, remarks at
CTBT Article XIV Conference, New York, NY, September 23, 2011, http://www.state.gov/t/us/173890.htm.
24 Rose Gottemoeller, “The Last U.S. Nuclear Test—20 Years Later: Status and Prospects for the Comprehensive Test
Ban Treaty,” remarks, Washington, DC, September 26, 2012, http://www.state.gov/t/us/198244.htm.
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Moniz and General Klotz have spoken about these two issues this afternoon and they are
strong allies in this effort.
We are and will continue to make it clear that a global ban on nuclear explosive testing will
hinder regional arms races and impede advancements in nuclear stockpiles around the world.
With an emphasis on a healthy, open dialogue, rather than a timeline, we are working with
the Senate to re-familiarize Members with the Treaty. A lot of CTBT-related issues have
changed since 1999, but the Senate has changed a lot since then, too. It is up to us, as
policymakers and experts before the American people, to practice due diligence in
consideration of this Treaty – that means briefings, hearings at the appropriate time, more
briefings, trips to Labs, trips to Vienna and the CTBTO, more briefings, etc., etc.. The
Senators should have every opportunity to ask questions, many questions, until they are
satisfied.
I want to make one thing very clear: this Administration has no intention of rushing this or
demanding premature action before we have had a thorough and rigorous discussion and
debate.25
In addressing the Seventh Ministerial Meeting on the CTBT in September 2014, Secretary of
State John Kerry said, “So I come here to reiterate the Obama Administration’s unshakable
commitment to seeing this treaty ratified and entered into force. And though we have not yet
succeeded in ratifying it for pure political, ideological reasons—not substance, I assure you—we
nevertheless are pledged to live by it, and we do live by it, and we will live by it.”26
In the run-up to the 2015 Nuclear Nonproliferation Treaty Review Conference, however, the
United States stressed its support for the treaty rather than efforts to secure Senate advice and
consent to ratification. In a report to the conference, the United States noted its financial support
for the CTBTO PrepCom and stated, “The United States fully supports the activities of the CTBT
Preparatory Commission as it makes the necessary preparations for the effective implementation
of the Treaty.”27 At the conference, Secretary of State John Kerry said, “We have clearly
demonstrated our commitment to abide by the Comprehensive Nuclear Test Ban Treaty.”28
United Kingdom: The United Kingdom cannot test because it held its nuclear tests for several
decades at the Nevada Test Site and does not have its own test site. Its last test was held in 1991.
Britain and France became the first of the original five nuclear weapon states to ratify the CTBT,
depositing instruments of ratification with the United Nations on April 6, 1998. On February 14,
2002, and February 23, 2006, the United Kingdom conducted subcritical experiments jointly with
the United States at the Nevada Test Site.

25 Rose Gottemoeller, Under Secretary of State for Arms Control and International Security, “Verification and Entry
Into Force of the CTBT,” http://www.state.gov/t/us/2014/231697.htm, remarks prepared for delivery at Embassy of
Kazakhstan et al., “Nuclear Weapons Testing: History, Progress, Challenges,” conference, Washington, D.C.,
September 15, 2014.
26 U.S. Department of State. “Remarks at the Friends of the Comprehensive Nuclear-Test-Ban Treaty Ministerial,”
John Kerry, Secretary of State, United Nations Headquarters, New York City, September 26, 2014,
http://www.state.gov/secretary/remarks/2014/09/232219.htm.
27 U.S. Department of State. “2015 U.S. National Report to the Nuclear Non-Proliferation Treaty Review Conference:
Comprehensive Nuclear Test Ban Treaty, U.S. Financial Support,” May 5, 2015, http://www.state.gov/documents/
organization/242085.pdf.
28 U.S. Department of State. John Kerry, Secretary of State. “Remarks at the 2015 Nuclear Nonproliferation Treaty
Review Conference,” New York, April 27, 2015, http://www.state.gov/secretary/remarks/2015/04/241175.htm.
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The United Kingdom and France maintain their own separate stockpile stewardship programs to
maintain existing warheads and, if necessary, develop new ones. For example, the U.K. Atomic
Weapons Establishment uses two sites: Aldermaston, which conducts R&D and some
manufacturing, and Burghfield, which conducts final assembly, maintenance, and
decommissioning of warheads.29 The United Kingdom and France are also pooling stockpile
stewardship resources. A declaration from the November 2010 U.K.-French summit announced
the decision by the two states
to collaborate in the technology associated with nuclear stockpile stewardship in support of
our respective independent nuclear deterrent capabilities, in full compliance with our
international obligations, through unprecedented co-operation at a new joint facility at
Valduc in France that will model performance of our nuclear warheads and materials to
ensure long-term viability, security and safety – this will be supported by a joint Technology
Development Centre at Aldermaston in the UK.30
Stockpile stewardship supports the stockpile, but at issue for the United Kingdom is what
weapons it will have in the future, and even whether it will have a nuclear force. The U.K.
nuclear force consists of Trident II (D-5) missiles aboard four ballistic missile submarines. With
the submarines approaching the end of their service lives, at issue is whether to replace them with
something other than ballistic missile submarines (e.g., bombers, land-based missiles, or missiles
on attack submarines), and if ballistic missile submarines are chosen, whether to build four or
fewer.
Scotland held a referendum on September 18, 2014, on whether to become an independent
country, and chose to remain part of the United Kingdom. Prior to the vote, there was
considerable concern over what would become of the U.K. nuclear deterrent if Scotland were to
become independent, as all U.K. ballistic missile submarines are based at Faslane, Scotland. In
October 2012, Alex Salmond, the leader of the Scottish National Party (SNP), said, “The SNP
Government will be bringing forward a white paper on independence which proposes a written
constitution for an independent Scotland, and that constitution will have to be ratified by the
Scottish Parliament elected in 2016. The SNP position on this is that the constitution should
include an explicit ban on nuclear weapons being based on Scottish territory.”31 If Scotland had
decided to become independent and to ban nuclear weapons in its territory, it is unclear what
steps Britain would have taken regarding its missile submarine force. Indeed, according to one
report of October 2012, “The UK defence secretary [Philip Hammond] said he was making no
contingency plans for moving Trident out of Scotland in the event of its people voting yes to
independence.”32 Another view put forward in August 2014 was that the Trident base could be

29 For further information on the Atomic Weapons Establishment, see its home page, http://www.awe.co.uk/. For
information on the French program, see France. Alternative Energies and Atomic Energy Commission. Military
Applications Division. “Nuclear Warheads and Nuclear Propulsion,” http://www.cea.fr/english_portal/defense/
nuclear_warheads_and_nuclear_propulsion2.
30 UK Prime Minister’s Office. “UK-France Summit 2010 Declaration on Defence and Security Co-operation,”
November 2, 2010, http://www.number10.gov.uk/news/statements-and-articles/2010/11/uk%E2%80%93france-
summit-2010-declaration-on-defence-and-security-co-operation-56519.
31 Scottish National Party, “Explicit Ban on Nuclear Weapons in Scotland,” October 7, 2012, http://www.snp.org/
media-centre/news/2012/oct/explicit-ban-nuclear-weapons-scotland.
32 “No Plan to Move Trident from Clyde, Says UK Minister Hammond,” BBC News, October 29, 2012,
http://www.bbc.co.uk/news/uk-scotland-scotland-politics-20121173.
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relocated to a site within England.33 However, Scotland’s vote to remain part of the United
Kingdom has rendered these concerns moot.
France: On June 13, 1995, President Jacques Chirac announced that France would conduct eight
nuclear tests at its test site at Mururoa Atoll in the South Pacific, finishing by the end of May
1996. The armed services had reportedly wanted the tests to check existing warheads, validate a
new warhead, and develop a computer system to simulate warheads to render further testing
unneeded. Many nations criticized the decision. On August 10, 1995, France indicated it would
halt all nuclear tests once the test series was finished and favored a CTBT that would ban “any
nuclear weapon test or any other nuclear explosion.”34 France conducted six tests from September
5, 1995, to January 27, 1996. On January 29, 1996, Chirac announced the end to French testing.
On April 6, 1998, France and Britain deposited instruments of ratification of the CTBT with the
United Nations. See the section on the United Kingdom, above, for information on a U.K.-French
collaboration on stockpile stewardship.
Russia: Several press reports between 1996 and 1999 claimed that Russia may have conducted
low-yield nuclear tests at its Arctic test site at Novaya Zemlya; other reports stated that U.S.
reviews of the data determined that these events were earthquakes. Several reports between 1998
and 2000 stated that Russia had conducted “subcritical” nuclear experiments, discussed below,
which the CTBT does not bar. The report of the Congressional Commission on the Strategic
Posture of the United States presents arguments for and against the CTBT; one argument by
opponents is, “Apparently Russia and possibly China are conducting low yield tests.”35 This
charge was reiterated in a September 2011 article: “Russia apparently has continued to test
nuclear weapons at very low yields, despite its commitment not to do so.”36
Russia ratified the treaty on June 30, 2000. In September 2005, Russia reportedly stated that it
intends to continue to observe the moratorium on testing until the CTBT enters into force as long
as other nuclear powers do likewise, and expressed its hope that the nations that must ratify the
treaty for it to enter into force will do so as soon as possible.37 In November 2007, according to
Itar-Tass, Russian Foreign Minister Sergei Lavrov “confirmed Russia’s unchanging support for
the treaty as one of the key elements of the nuclear non-proliferation regime and an effective
nuclear arms limitation tool.”38 In September 2009, Dmitry Medvedev, president of the Russian
Federation, said, “we need to encourage leading countries to sign and ratify the Comprehensive
Nuclear-Test-Ban Treaty as soon as possible in order to ensure its ultimate entry into force. That
is very important.”39

33 Richard Norton-Taylor, “Trident missiles ‘could be relocated to Plymouth from independent Scotland,’” The
Guardian,
August 13, 2014, http://www.theguardian.com/uk-news/2014/aug/14/trident-missiles-relocate-plymouth-
independent-scotland-rusi-report.
34 Craig Whitney, “France to Back Ban After Its Atom Tests,” New York Times, August 11, 1995, p. 3.
35 Congressional Commission on the Strategic Posture of the United States, America’s Strategic Posture, Washington,
DC, United States Institute of Peace Press, 2009, p. 83.
36 R. James Woolsey and Keith Payne, “Reconsidering the Comprehensive Test Ban Treaty,” National Review Online,
September 8, 2011, http://www.nationalreview.com/articles/276530/reconsidering-comprehensive-test-ban-treaty-r-
james-woolsey.
37 “Russia Intends to Continue Moratorium on Nuclear Tests,” BBC Monitoring Former Soviet Union, excerpt from a
report by Russian News Agency ITAR-TASS, September 23, 2005.
38 “Russia Supports CTBT as Key Element of Nuclear Non-Proliferation—FM,” Itar-Tass, November 12, 2007.
39 United Nations. Security Council. 6191st meeting, September 24, 2009, S/PV.6191, provisional version, p. 7.
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A Russian scholar at the Russian Academy of Sciences raised the prospect of the CTBT’s collapse
in an article of November 2010. Claiming that Britain and France have ratified the treaty but do
not have a moratorium on testing, that the reverse is the case for China and the United States, that
India, Israel, North Korea, and Pakistan have done neither, and that only Russia has ratified the
treaty and has a moratorium on testing, he argued that
if the treaty has not been in force for fifteen years [i.e., since it was opened for signature in
1996], it is difficult for Russia to be the only nuclear power which complies with its terms
and conditions in full. Russia’s official position is to support the CTBT’s entry into force.
However, Russian experts tend to focus on the pessimistic scenarios of CTBT collapse. In
the near future, Russia could face a difficult choice between the political dividends the CTBT
affords and the military necessity to upgrade its nuclear capabilities.40
At the 2011 Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-
Ban Treaty, Sergey Ryabkov, Deputy Minister of Foreign Affairs of the Russian Federation,
expressed his country’s support for the treaty and said, “We hope that our call upon the respective
States to sign and/or ratify the CTBT will finally be heard by them.”41 At the 2015 Nuclear
Nonproliferation Treaty Review Conference, Mikhail Uliyanov, acting head of the Russian
Federation’s delegation, said, “We are deeply concerned by the lack of any tangible progress in
the Comprehensive Nuclear-Test-Ban Treaty (СTBT) coming into force. We recall that our
country ratified the CTBT in 2000, and we are working hard to make it universal both in bilateral
and multilateral formats.”42
China: China did not participate in the moratorium. It conducted a nuclear test on October 5,
1993, that many nations condemned. It countered that it had conducted 39 tests, as opposed to the
1,054 that the United States had conducted, and needed a few more for safety and reliability.
According to one report, “China will immediately stop nuclear testing once the treaty on the
complete ban of nuclear tests takes effect, [Chinese Premier] Li Peng said.”43 It conducted other
tests on June 10 and October 7, 1994, May 15 and August 17, 1995, and June 8 and July 29,
1996. It announced that the July 1996 test would be its last, as it would begin a moratorium on
July 30, 1996. On February 29, 2000, the Chinese government submitted the CTBT to the
National People’s Congress for ratification. In a white paper of December 2004, China stated its
support of early entry into force and, until that happens, its commitment to the test moratorium.
As of June 2015, China had signed but not ratified the treaty.

40 Alexei Fenenko, Leading Research Fellow, Institute of International Studies, Russian Academy of Sciences, “Russia
and the Future of the CTBT,” RIA Novosty, November 3, 2010, http://en.rian.ru/valdai_op/20101103/161192733.htm.
Note that France dismantled its nuclear test site: “Two-thirds of French Mururoa N-test Site Dismantled,” Reuters,
September 13, 1997. The 1997 article quotes the site commander as saying that dismantlement would be completed by
July 1998. Also, the United Kingdom conducted all its nuclear tests at the Nevada Test Site for many years, so it could
not conduct tests unless it were to build its own test site or the United States were to end its nuclear test moratorium.
41 Russian Federation. Permanent Mission to the United Nations. “Statement by the Head of Delegation of the Russian
Federation, Deputy Foreign Minister Sergey A. Ryabkov, at the 7th Conference on Facilitating the Entry into Force of
the Comprehensive Nuclear-Test-Ban Treaty,” New York, September 23, 2011, http://www.ctbto.org/fileadmin/
user_upload/Art_14_2011/Statements/Russia.pdf.
42 Russian Federation. Permanent Mission of the Russian Federation to the United Nations in New York. Statement by
Mikhail Ulianov, Acting Head of the Delegation of the Russian Federation at the 2015 Review Conference of the
Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, April 27, 2015, http://www.un.org/en/conf/npt/
2015/statements/pdf/RU_en.pdf.
43 “Li Peng: China’s Nuclear Tests Pose No Threat,” Xinhua, October 8, 1995, in FBIS-TAC-95-006, December 6,
1995, p. 13.
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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

India: On May 11, 1998, Prime Minister Atal Behari Vajpayee announced that India had
conducted three nuclear tests. The government stated, “The tests conducted today were with a
fission device, a low yield device and a thermonuclear device.... These tests have established that
India has a proven capability for a weaponised nuclear programme.”44 It announced two more
tests May 13. An academic study concluded, based on seismic data, that India and Pakistan
overstated the number and yields of their tests. India has conducted no tests since May 1998, but
questioned whether the United States should expect India to sign a treaty that the United States
views as flawed. In an Indian-Pakistani statement of June 20, 2004, “Each side reaffirmed its
unilateral moratorium on conducting further nuclear test explosions” barring “extraordinary
events.”45 On December 22, 2005, Shri Rao Inderjit Singh, Minister of State in the Ministry of
External Affairs, said, “India has already stated that it will not stand in the way of the Entry into
Force of the Treaty.”46 On August 16, 2007, India’s External Affairs Minister, Pranab Mukherjee,
reportedly told Parliament, “India has the sovereign right to test and would do so if it is necessary
in national interest.”47
A statement on U.S.-Indian nuclear cooperation of July 18, 2005, by President Bush and Indian
Prime Minister Manmohan Singh, said, “The Prime Minister conveyed that for his part, India
would reciprocally agree that it would be ready to ... continu[e] India’s unilateral moratorium on
nuclear testing.”48 In a Senate hearing of November 2, Robert Joseph, Under Secretary of State
for Arms Control and International Security, stated, “India’s pledge to maintain its nuclear testing
moratorium contributes to nonproliferation efforts by making its ending of nuclear explosive tests
one of the conditions of full civil nuclear cooperation.”49 At that hearing, Michael Krepon, co-
founder of the Stimson Center, argued that statements by Indian government officials that there
are no current plans to test “do not carry equal weight, nor do they impose equal responsibility, to
the obligations accepted by the 176 states that have signed the CTBT.”50 Press reports of April
2006 said the sides were negotiating a detailed nuclear cooperation agreement. The reports
indicated that the United States would insist that India maintain its nuclear test moratorium or
else the United States would have the right to terminate the agreement. India responded that it had
pledged to maintain the moratorium, rendering this provision out of place in the final agreement.
A press report of January 2007 quoted National Security Advisor M.K. Narayanan as saying,
“There is no question of signing the Comprehensive Test Ban Treaty. We have our voluntary
moratorium. That position remains.”51 According to a report of November 2007, when some

44 India. Ministry of External Affairs. Press statement, New Delhi, May 11, 1998, at http://nuclearweaponarchive.org/
India/Indianofficial.txt.
45 India. Ministry of External Affairs. “Joint Statement, India-Pakistan Expert-Level Talks on Nuclear CBMs
[Confidence-Building Measures],” June 20, 2004.
46 India. Ministry of External Affairs. Rajya Sabha. Unstarred Question No. 3260, to be answered on December 12,
2005, by Rao Inderjit Singh, Minister of State in the Ministry of External Affairs. http://164.100.24.219/rsq/quest.asp?
qref=108782.
47 “Pranab Mukherjee Says India Has Sovereign Right to Conduct Nuclear Test,” AndhraNews.net, August 16, 2007;
available at http://www.andhranews.net/India/2007/August/16-Pranab-Mukherjee-says-11996.asp.
48 U.S. White House. “Joint Statement Between President George W. Bush and Prime Minister Manmohan Singh,” July
18, 2005, at http://www.whitehouse.gov/news/releases/2005/07/20050718-6.html.
49 U.S. Congress. Senate. Committee on Foreign Relations. Hearing, Implications of U.S.-India Nuclear Energy
Cooperation
, statement by Robert Joseph, Under Secretary of State for Arms Control and International Security,
November 2, 2005. Transcript by CQ Transcriptions, Inc.
50 U.S. Congress. Senate. Committee on Foreign Relations. Hearing, Implications of U.S.-India Nuclear Energy
Cooperation
, statement by Michael Krepon, Co-Founder, The Henry L. Stimson Center, November 2, 2005. Transcript
by CQ Transcriptions, Inc.
51 “India Not to Accept Any Legal Binding on N-Testing,” Press Trust of India Limited, January 13, 2007.
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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

members of Parliament criticized the U.S.-Indian nuclear agreement on grounds it would bar
Indian nuclear testing, Prime Minister Manmohan Singh responded, “If a necessity for carrying
out a nuclear test arises in future, there is nothing in the agreement which prevents us from
carrying out tests.”52 (See CRS Report R42948, U.S.-India Security Relations: Strategic Issues,
by K. Alan Kronstadt and Sonia Pinto.)
In August 2009, a former Indian official said that India should not be “railroaded” into signing the
CTBT because its hydrogen bomb tests of 1998 did not produce the desired yield. Accordingly, he
said, India “should conduct more nuclear tests which are necessary from the point of view of
security.”53 In response, other Indian officials claimed that the thermonuclear tests were
successful, so no further tests were needed.54 In December 2009, in response to “the renewed
pressure from President Obama on [India] in recent months to sign the CTBT,” 11 scientists and
others formerly in the Indian nuclear weapons program urged the Indian government not to sign
the treaty.55 In October 2010, a trade agreement in which Japan would sell civilian nuclear
technology to India had stalled as Japan urged India to take steps toward signing the CTBT.56
Meanwhile, India continues to develop its nuclear weapons program. For example, press reports
in 2014 described construction in India of a nuclear-powered submarine for carrying nuclear-
armed ballistic missiles,57 a test of this type of missile,58 construction of an Indian uranium
enrichment plant,59 and a test of a missile defense interceptor.60 Press reports of April 2015
indicated that India had tested a nuclear-armed ballistic missile with a range of 3,000 km61 and
was working to develop missile defenses.62 As of June 2015, India had not signed the CTBT.
Pakistan: Pakistan announced on May 28, 1998, that it had conducted five nuclear tests, and
announced a sixth on May 30. Reports placed the yields of the smallest devices between zero and
a few kilotons, and between 2 and 45 kilotons for the largest. Some question the number of tests
based on uncertain seismic evidence. Pakistan made no claims of testing fusion devices.
Pakistan’s weapons program apparently relies heavily on foreign technology. Pakistan claimed
that it tested “ready-to-fire warheads,” not experimental devices, and included a warhead for the
Ghauri, a missile with a range of 900 miles, and low-yield tactical weapons. In response to the

52 “Indian Lawmakers Attack U.S. Nuclear Deal,” Global Security Newswire, November 29, 2007.
53 “No CTBT, India Needs More Nuclear Tests: Pokhran II Coordinator,” The Times of India, August 27, 2009.
54 “Top Indian Scientists Say Nuclear Tests Were Successful,” Global Security Newswire, September 25, 2009.
55 P.K. Iyengar et al., “On Thermonuclear Weapon Capability and Its Implications for Credible Minimum Deterrence:
Statement by Deeply Concerned Senior Scientists,” Mainstream, December 26, 2009,
http://www.mainstreamweekly.net/article1865.html.
56 “Japan-India Atomic Trade Talks Stall over CTBT,” Global Security Newswire, October 26, 2010, http://gsn.nti.org/
gsn/nw_20101026_7486.php.
57 Pallava Bagla, Vishnu Som, “NDTV Exclusive: This is INS Arihant, First Made-in-India Nuclear Submarine,”
August 20, 2014, NDTV.com, http://www.ndtv.com/article/india/ndtv-exclusive-this-is-ins-arihant-first-made-in-india-
nuclear-submarine-578949?curl=1408544078.
58 “India Reveals Secret Underwater Test-Launch of Ballistic Missile,” Global Security Newswire, May 12, 2014,
http://www.nti.org/gsn/article/india-reveals-secret-underwater-test-launch-ballistic-missile/.
59 David Albright and Serena Kelleher-Vergantini, “India’s New Uranium Enrichment Plant in Karnataka,” Institute for
Science and International Security, July 1, 2014, http://www.isis-online.org/uploads/isis-reports/documents/
SMEF_Brief_July_1_2014_FINAL.pdf.
60 “Success Questioned in Much-Hyped Indian Antimissile Test,” Global Security Newswire, May 15, 2014,
http://www.nti.org/gsn/article/indias-much-hyped-intercept-test-might-not-have-been-such-success/.
61 “India Successfully Test Fires 3,000 km Range Nuclear Missile,” Prensa Latina, April 16, 2015.
62 “Test of Missile Interceptor for Aerial Shield Fails,” The Times of India, April 7, 2015.
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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

Indian and Pakistani tests, the United States imposed economic sanctions on the two nations. In
November 1999, Foreign Minister Abdul Sattar said that his nation would not sign the CTBT
unless sanctions were lifted, but that “[w]e will not be the first to conduct further nuclear tests.”63
In August 2000, President Pervez Musharraf said the time was not ripe to sign the CTBT because
so doing could destabilize Pakistan.64 In September 2005, Pakistan reportedly said it would not be
the first nation in the region to resume nuclear testing.65 In April 2007, Pakistan’s Prime Minister,
Shaukat Aziz, reportedly said that Pakistan would not unilaterally sign the CTBT since it shares a
border with India.66 Replying to the statement on nuclear testing by Pranab Mukherjee, India’s
External Affairs Minister, Tasnim Aslam, a spokeswoman for Pakistan’s Foreign Office,
reportedly said, “We take seriously the assertions by the Indian leadership about the possibility of
renewing nuclear tests.... Resumption of nuclear tests by India would create a serious situation
obliging Pakistan to review its position and to take action, appropriate, consistent to our supreme
national interest.”67 According to a press report of June 2009, the situation had changed: “‘Let me
tell you, Pakistan has no plan to sign the CTBT,’ Pakistani Foreign Ministry spokesman Abdul
Basit said, adding that circumstances have changed since Islamabad pledged in 1998 to sign off
on the agreement if nuclear rival India did the same.”68 Meanwhile, like India, Pakistan continues
development of its nuclear weapons program. Reports of 2014 describe the start of operations of a
third plutonium reactor, with a fourth apparently still under construction69 and the test firing of a
ballistic missile.70 A report of February 2015 indicated that Pakistan may have finished a
plutonium separation plant, which, if true, would increase that country’s ability to make nuclear
weapons.71 As of June 2015, Pakistan had not signed the CTBT.
The North Korean Nuclear Tests
The October 2006 Nuclear Test
Negotiations to halt North Korea’s nuclear program have been underway for years, most recently
between that nation, the United States, China, Japan, South Korea, and Russia (Six-Party Talks).
A CIA report of late 2004 stated that during talks in April 2003, “North Korea privately

63 Kathy Gannon, “New Pakistani Government Gives First Official Foreign Policy Statement,” newswire, Associated
Press, November 8, 1999.
64 Shahid-ur-Rehman Khan, “Signing CTBT Can Destabilize Pakistan, Says Musharraf,” newswire, Kyodo News
International, Inc., August 17, 2000.
65 “Pakistan Today Said It Will Abide by Its ‘Solemn Pledge’ That It Would Not Be the First Country in the Region to
Resume Nuclear Tests ...,” newswire, Press Trust of India Limited, September 26, 2005.
66 “Pak Says No to Signing NPT, CTBT Unilaterally,” Press Trust of India Limited, April 26, 2007.
67 “Pakistan Would Consider Nuclear Test If India Tests,” Reuters, August 20, 2007, available at http://in.reuters.com/
article/topNews/idINIndia-29063920070820.
68 “Pakistan Rules Out Test Ban Treaty Endorsement,” Global Security Newswire, June 19, 2009.
69 Zia Mian, “Pakistan Begins Operating Third Khushab Plutonium Production Reactor,” International Panel on Fissile
Materials IFPM Blog, June 30,2014, http://fissilematerials.org/blog/2014/06/pakistan_begins_operating.html.
70 “Pakistan Test Fires Nuclear-Capable Ballistic Missile,” Post TV/Reuters, April 22, 2014,
http://www.washingtonpost.com/posttv/national/pakistan-test-fires-nuclear-capable-ballistic-missile/2014/04/22/
32f003d2-ca02-11e3-b81a-6fff56bc591e_video.html.
71 “Pakistan’s Chashma Plutonium Separation Plant: Possibly Operational,” by David Albright and Serena Kelleher-
Vergantini, Institute for Science and International Security, February 20, 2015.
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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

threatened to ‘transfer’ or ‘demonstrate’ its nuclear weapons.”72 On February 10, 2005, North
Korea declared, “We ... have manufactured nukes for self-defence to cope with the Bush
administration’s evermore undisguised policy to isolate and stifle North Korea,”73 and on June 9 it
claimed it was building more such weapons. On May 15, 2005, the United States warned that it
and other nations would take punitive action if North Korea conducted a nuclear test.74 In a joint
statement from the Six-Party Talks in September 2005, North Korea “committed to abandoning
all nuclear weapons and existing nuclear programs and returning, at an early date, to the Treaty on
the Non-Proliferation of Nuclear Weapons and to IAEA safeguards.”75 In November 2005, North
Korea began a boycott of the talks. On October 3, 2006, North Korea stated that it “will, in the
future, be conducting a nuclear test.”76 In response, Japan, the United Kingdom, and the United
States warned of consequences if North Korea conducted a test; South Korea expressed “deep
regret and concern.” For updates on nuclear diplomacy, see CRS Report R41259, North Korea:
U.S. Relations, Nuclear Diplomacy, and Internal Situation
, by Emma Chanlett-Avery and Ian E.
Rinehart.
On October 9, 2006, North Korea declared that it had conducted an underground nuclear test. One
report placed the yield at as little as 0.2 kilotons.77 According to other reports, South Korean
geologists placed the explosive yield at 550 tons of TNT equivalent (0.55 kilotons),78 the French
Atomic Energy Commission’s estimate was 0.50 kilotons,79 and Russian Minister of Defense
Sergei Ivanov placed the yield at 5 to 15 kilotons.80 For comparison, the Hiroshima bomb had a
yield of 15 kilotons. A yield of less than a kiloton is well below the 9 or more kilotons of other
nations’ first nuclear tests,81 and below the 4 kilotons that North Korea reportedly told China that
it expected.82 On October 16, the Office of the Director of National Intelligence released a
statement on the test: “Analysis of air samples collected on October 11, 2006 detected radioactive
debris which confirms that North Korea conducted an underground nuclear explosion in the
vicinity of P’unggye on October 9, 2006. The explosion yield was less than a kiloton.”83

72 “Attachment A: Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass
Destruction and Advanced Conventional Munitions, 1 July Through 31 December 2003.” Note: “The Director of
Central Intelligence (DCI) hereby submits this report in response to a congressionally directed action in Section 721 of
the FY1997 Intelligence Authorization Act ...,” c. 2004, p. 5.
73 “Korean Central News Agency North Korea February 10,” The Guardian, February 12, 2005.
74 David Sanger, “U.S. in Warning to North Korea on Nuclear Test,” New York Times, May 16, 2005, p. 1.
75 “Joint Statement of the Fourth Round of the Six-Party Talks,” Beijing, September 19, 2005, at http://www.state.gov/
r/pa/prs/ps/2005/53490.htm.
76 Democratic People’s Republic of Korea, Foreign Ministry Statement, Pyongyang Korean Central Broadcasting
Station, October 3, 2006.
77 “White House Casts Doubt on N. Korean Nuclear Arms,” Reuters newswire, October 10, 2006.
78 Evan Ramstad, Jay Solomon, and Gordon Fairclough, “Bomb Fallout: Explosion by North Koreans Imperils
Nuclear-Control Effort,” Wall Street Journal, October 10, 2006, p. 1.
79 Michael Abramowitz and Colum Lynch, “U.S. Urges Sanctions on North Korea,” Washington Post, October 10,
2006, in graphic, “North Korea’s Big Test,” p. 13.
80 William Broad and Mark Mazzetti, “Blast May Be Only a Partial Success, Experts Say,” New York Times, October
10, 2006, p. 8.
81 James Sterngold, “U.S. Urges Sanctions to Restrain North Korea,” San Francisco Chronicle, October 10, 2006, p. 1.
82 Broad and Mazzetti, “Blast May Be Only a Partial Success, Experts Say.”
83 U.S. Office of the Director of National Intelligence. Public Affairs Office. “Statement by the Office of the Director
of National Intelligence on the North Korea Nuclear Test,” October 16, 2006, ODNI News Release No. 19-06, 1 p.
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Most U.S. observers cited in news reports believe the event was a small nuclear explosion, but at
most a partial success. One hypothesis is that, through poor design, the device did not implode
properly, greatly reducing its yield.84 Other hypotheses are that the device reduced the amount of
plutonium used in order to conserve that material, or engineers sought to test the design rather
than yield of the device, or the device was smaller and more sophisticated than anticipated.85 On
the latter point, Siegfried Hecker, former director, Los Alamos National Laboratory, stated that
the North Korean weapon designers most likely did not test a Nagasaki-type device (a basic
implosion device) because they could have had high confidence, without testing, that such a
device would work. Instead, his analysis is that the North Koreans most likely tested a more
advanced design, even at the risk of partial failure, which is what the seismic signals appear to
confirm. He considers it highly unlikely that they intentionally designed a mini-nuke. However,
even if the test was not fully successful, he believes they learned much from the test.86
A more advanced warhead would be of greater military value to North Korea than a Nagasaki
bomb because a missile could carry it, but further tests might well be needed to make the warhead
militarily usable. The press carried reports that North Korea said it would not conduct further
tests, but according to another report, Secretary of State Condoleezza Rice said that Chinese
officials, briefing her on the North Korean situation, said nothing about a North Korean test
halt.87 It would take some time to prepare for another test by determining the lessons of the first
test, redesigning the device, and testing components of the new design. A moratorium during that
time would have little if any impact on its test program.
The seismic record of the North Korean test, when compared with recordings of a 2002
earthquake recorded at a seismic station in Wonju, Republic of Korea, shows differences in
seismic wave patterns that are diagnostic of an explosive source.88 For example, seismic waves
from the earthquake build up over several seconds, while waves from the explosion arrive
suddenly. Once the amplitudes are measured, the yield may be estimated, but this is complicated
by factors such as the local geology and the specifics of the burial. Arthur Lerner-Lam, Associate
Director for Seismology, Geology, and Tectonophysics, Lamont-Doherty Earth Observatory,
Columbia University, said that the seismic record is not useful for determining whether the event
was a nuclear or conventional explosion without making additional assumptions or inferences.89
Mining explosions are typically detonated over several seconds in order to break rock efficiently,
so their seismological signature can be interpreted in terms of such “ripple firing.” However, if
North Korea attempted to mimic the signature of a nuclear explosion by setting off all the
explosive at the same time, Lerner-Lam said, it would be virtually impossible to discriminate
between conventional and nuclear explosions using seismological data alone. Complementary
observations provide more direct evidence. A nuclear explosion releases radioactive isotopes of

84 Dafna Linzer and Thomas Ricks, “U.S. Waits for Firm Information on Nature and Success of Device,” Washington
Post,
October 11, 2006, p. 14.
85 Dafna Linzer, “Low Yield of Blast Surprises Analysts,” Washington Post, October 10, 2006, p. 12.
86 Personal communication, October 13, 2006.
87 Burt Herman, “U.S. Says No Sign of NKorea Promise Not to Test; SKorea’s Ex-President Warns of Backlash,”
Associated Press Newswires, October 21, 2006.
88 For the two seismographs, see “The CTBT Verification Regime Put to the Test—The Event in the DPRK on 9
October 2006,” Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, at http://www.ctbto.org/
press_centre/featured_articles/2007/2007_0409_dprk.htm. For a detailed discussion of the seismic record of the North
Korean test, see Paul Richards and Won-Young Kim, “Seismic Signature,” Nature Physics, January 2007, pp. 4-6.
89 Personal communication, October 10, 2006.
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certain gases. They may take days to reach the surface, but once they dissipate into the
atmosphere, he said, they may be detected by specially equipped aircraft or ground stations.90
The ability of the seismic network to detect an explosion that most sources place at or below one
kiloton, and in one case as low as 0.2 kiloton, may hold implications for the CTBT. The treaty’s
supporters claim that the ability to detect subkiloton tests should negate arguments against the
treaty on grounds of inadequate monitoring capability. The CTBTO PrepCom, for example,
states, “the CTBT verification regime proved that it was capable of meeting the expectations set
for it,”91 even though the test was low yield, the IMS was 60% completed, and the noble gas
system was 25% completed.92 Critics respond that the test was not evasively conducted; that
evasion scenarios, such as testing during an earthquake or in a large underground cavity, could
defeat monitoring efforts; and that subkiloton tests could aid in developing nuclear weapons.
The May 2009 Nuclear Test
North Korea announced on May 25, 2009, that it had conducted a second nuclear test.93 The U.S.
Office of the Director of National Intelligence stated: “The U.S. Intelligence Community assesses
that North Korea probably conducted an underground nuclear explosion in the vicinity of
P'unggye on May 25, 2009. The explosion yield was approximately a few kilotons. Analysis of
the event continues.”94 The lack of certainty on whether the test was nuclear arises because
seismic signals, including those detected by 61 stations of the International Monitoring System
(IMS, described below),95 were consistent with a nuclear test, and seismic signals from the 2006
and 2009 events were very similar,96 but open sources did not report the detection of physical
evidence that would provide conclusive proof of a nuclear test, such as radioactive isotopes of
noble gases, especially those having short half-lives, or radioactive particulates (i.e., fallout). For
example, the CTBTO PrepCom stated:
The detection of radioactive noble gas, in particular xenon, could serve to corroborate the
seismic findings. Contrary to the 2006 announced DPRK nuclear test, none of the CTBTO’s
noble gas [detection] stations have detected xenon isotopes in a characteristic way that could

90 For a technical analysis of the North Korean test, see Richard Garwin and Frank von Hippel, “A Technical Analysis:
Deconstructing North Korea’s October 9 Nuclear Test,” Arms Control Today, November 2006.
91 “The CTBT Verification Regime Put to the Test—The Event in the DPRK on 9 October 2006.” This source also has
links to many documents on the North Korean test.
92 Information provided by CTBTO PrepCom, personal communication, February 15, 2008.
93 For further information on North Korea’ nuclear program, see CRS Report RL33590, North Korea’s Nuclear
Weapons Development and Diplomacy
, by Larry A. Niksch, and CRS Report RL34256, North Korea’s Nuclear
Weapons: Technical Issues
, by Mary Beth D. Nikitin.
94 U.S. Office of the Director of National Intelligence. Public Affairs Office. “Statement by the Office of the Director
of National Intelligence on North Korea’s Declared Nuclear Test on May 25, 2009,” ODNI News Release No. 23-09,
June 15, 2009, at http://www.dni.gov/press_releases/20090615_release.pdf .
95 Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, “Homing in on the Event,” May 29, 2009,
http://www.ctbto.org/press-centre/highlights/2009/homing-in-on-the-event/.
96 For seismograms of these two events and an earthquake from the same region, see Won-Young Kim, Paul Richards,
and Lynn Sykes, “Discrimination of Earthquakes and Explosions Near Nuclear Test Sites Using Regional High-
Frequency Data,” poster SEISMO-27J presented at the International Scientific Studies conference, June 2009,
http://www.ctbto.org/fileadmin/user_upload/ISS_2009/Poster/SEISMO-27J%20%28US%29%20-
%20Won_Young_Kim%20_Paul_Richards%20and%20Lynn_Sykes.pdf.
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be attributed to the [2009] DPRK event so far, even though the system is working well and
the network’s density in the region is considerably higher than in 2006....
Nor have CTBTO Member States using their own national technical means reported any
such measurements. Given the relatively short half-life of radioactive xenon (between 8
hours and 11 days, depending on the isotope), it is unlikely that the [International Monitoring
System] will detect or identify xenon from this event after several weeks.97
Possible reasons why no radioactive effluents were detected include progress in containment of
such effluents by North Korea, drawing on lessons learned from the 2006 test; detailed study of
the geology at the test site to locate the test away from potential pathways by which the effluents
could reach the surface; release of effluents below the threshold of detection; the possibility that
the test was a large chemical explosion; good luck; or some combination. For further discussion
of the 2009 test, see CRS Report R41160, North Korea’s 2009 Nuclear Test: Containment,
Monitoring, Implications
, by Jonathan E. Medalia.
In response to the event, the U.N. Security Council adopted resolution 1874 on June 12, 2009.98
Among other things, the resolution “express[es] the gravest concern” at the nuclear test,
“condemns in the strongest terms the nuclear test,” calls for inspection of cargo to and from North
Korea under certain circumstances and conditions, and provides for various financial sanctions.
(See CRS Report R40684, North Korea’s Second Nuclear Test: Implications of U.N. Security
Council Resolution 1874
, coordinated by Mary Beth D. Nikitin and Mark E. Manyin.)
A Test in May 2010?
In early May 2010, radionuclide stations of the IMS detected radioactive isotopes of xenon and
other elements. The data were puzzling, especially as there were very faint seismic signals that
could have been from the event and because North Korea issued a statement in that month
claiming it had achieved nuclear fusion.99 A seismologist, Lars-Erik De Geer, presented evidence
that the test had come from a North Korean nuclear explosion of very low yield, less than 1
kiloton.100 That finding led to considerable and continuing debate on whether the signals came
from a North Korean test or something else, and if the former, what they signify.101

97 Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission, “Experts Sure about the Nature of
the DPRK Event,” (referring to the May 2009 North Korean test), June 12, 2009, http://www.ctbto.org/press-centre/
highlights/2009/experts-sure-about-nature-of-the-dprk-event/. The International Monitoring System is a system to
detect nuclear explosions worldwide. It is being built up by the Comprehensive Nuclear-Test-Ban Treaty Organization
Preparatory Commission. See http://www.ctbto.org/verification-regime/.
98 United Nations. Security Council. Resolution 1874 (2009) adopted by the Security Council at its 6141st meeting, on
12 June 2009, S/Res/1874 (2009), http://daccess-dds-ny.un.org/doc/UNDOC/GEN/N09/368/49/PDF/N0936849.pdf?
OpenElement.
99 Geoff Brumfiel, “Isotopes Hint at North Korean Nuclear Test,” Nature, February 3, 2012, http://www.nature.com/
news/isotopes-hint-at-north-korean-nuclear-test-1.9972.
100 Lars-Erik De Geer, “Radionuclide Evidence for Low-Yield Nuclear Testing in North Korea in April/May 2010,”
Science and Global Security 20, no. 1 (2012): 1-29, http://scienceandglobalsecurity.org/archive/sgs20degeer.pdf.
101 See Lars-Erik De Geer, “The Great 2010 DPRK Nuclear Test Debate: Summarizing the Evidence of a Low-Yield
Nuclear Test Carried out in North Korea in May 2010,” 38 North (website), May 19, 2015, http://38north.org/2015/05/
ledegeer051915/#_ftn1; Jeffrey Lewis, “The Great 2010 DPRK Nuclear Test Debate,” 38 North, April 28, 2015,
http://38north.org/2015/04/jlewis042815/; and Joel Wit and Sun Young Ahn, “The Great 2010 DPRK Nuclear Test
Debate Continues: Imagery Evidence Inconclusive,” 38 North, April 28, 2015, http://38north.org/2015/04/
punggye042815/.
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The February 2013 Nuclear Test
Since shortly after the second test, there were conflicting, ambiguous, or speculative reports on
whether North Korea was preparing for another nuclear test, with some as recent as late 2012.102
In early 2013 North Korea announced that it would conduct another nuclear test, and it did so on
February 12, 2013. Reuters quoted North Korea’s state-run Korean Central News Agency as
saying, “It was confirmed that the nuclear test that was carried out at a high level in a safe and
perfect manner using a miniaturized and lighter nuclear device with greater explosive force than
previously did not pose any negative impact on the surrounding ecological environment.”103
The Office of the Director of National Intelligence issued the following statement: “The U.S.
Intelligence Community assesses that North Korea probably conducted an underground nuclear
explosion in the vicinity of P’unggye on February 12, 2013. The explosion yield was
approximately several kilotons. Analysis of the event continues.”104 The U.S. Geologic Survey
stated that the test had a seismic magnitude of 5.1.105 The Preparatory Commission for the
Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) operates the International
Monitoring System (IMS, described in more detail below), which consists of a global network of
seismographs and other instruments to detect nuclear tests, laboratories to analyze certain types of
data, and an International Data Center (IDC) to further analyze data and disseminate the
results.106 On February 12, CTBTO stated, “The CTBTO’s first and preliminary automatic
detections were made by up to 25 seismic stations around the world. The first data were made
available to CTBTO Member States in little more than one hour, and before the DPRK’s
announcement. The event measured 5.0 in magnitude, which is around twice as large as the
DPRK’s nuclear test in 2009 (4.52) and much larger than the one in 2006 (4.1).”107 (Seismic
magnitude is measured on a logarithmic scale; a magnitude 5 event is 10 times as large as a
magnitude 4 event.) Seismic magnitude is an approximate measure of yield, as the magnitude
detected at an individual seismic station can be affected by the type of rock or soil in which the
test is conducted; whether the rock or soil is wet or dry (rock or soil saturated with water
transmits a seismic signal more efficiently); whether the test device was packed tightly into the

102See, for example, David Chance, “For North Korea, Next Step Is a Nuclear Test,” Reuters, December 13, 2012,
http://www.reuters.com/article/2012/12/13/us-korea-north-rocket-idUSBRE8BB02K20121213; “Ex-USFK [U.S.
Forces Korea] Commander Warns Against North’s Nuclear and Missile Threats,” Korea Times, September 13, 2012,
http://www.koreatimes.co.kr/www/news/nation/2012/09/205_119828.html; and Foster Klug and Matthew Pennington,
“Photos Show NKorea Nuclear Readiness,” Associated Press/ABC News, December 28, 2012, http://abcnews.go.com/
International/wireStory/ap-exclusive-photos-show-nkorea-nuclear-readiness-18079671.
103 Jack Kim, “North Korea Confirms ‘Successful’ Nuclear Test: KCNA,” Reuters, February 12, 2013.
104 Office of the Director of National Intelligence, Statement by the Office of the Director of National Intelligence on
North Korea’s Declared Nuclear Test on February 12, 2013
, February 12, 2013, http://www.dni.gov/index.php/
newsroom/press-releases/191-press-releases-2013/809-statement-by-the-office-of-the-director-of-national-intelligence-
on-north-korea’s.
105 U.S. Geologic Survey, Poster of the North Korea Seismic Event of 12 February 2013 - Magnitude 5.1, February 12,
2013, http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2013/20130212.php.
106 For information on this monitoring system, see Preparatory Commission for the Comprehensive Nuclear-Test-Ban
Treaty Organization, “Verification Regime,” http://www.ctbto.org/verification-regime/. Many other seismographs not
part of the IMS can contribute data on seismic events. See, for example, Incorporated Research Institutions for
Seismology, “Global Seismographic Network” (map), January 2013, http://www.iris.edu/hq/programs/gsn/maps. In
addition, the United States and other nations have their own equipment for monitoring nuclear testing.
107 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, On the CTBTO’s Detection
in North Korea
, Vienna, Austria, February 12, 2013, http://www.ctbto.org/press-centre/press-releases/2013/on-the-
ctbtos-detection-in-north-korea/.
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rock or soil, which would transmit seismic waves more efficiently, or placed in a large cavity,
which would muffle the signal; the types and locations of rock formations between the test site
and the seismic station; and so on. By February 15, 96 IMS stations had sent data to the IDC.108
Since many IMS seismic stations detected the test, the CTBTO had ample data for estimating the
location of the test, placing it near North Korea’s previous tests. The data also permitted
estimating the depth of the test. Seismic signals originating deep in the earth indicate that the
source was an earthquake; signals originating near the surface are consistent with either an
earthquake or an explosion. The data indicated a shallow depth for the event.
A key question is whether the device used uranium or plutonium. Since it requires less plutonium
than uranium to sustain a fission reaction, a nuclear weapon made using plutonium can be smaller
and lighter than one made using uranium. A plutonium warhead could thus be more readily
carried by a missile, or carried to a longer range, than a uranium warhead. However,
it appears that plutonium is a dead end for Pyongyang’s nuclear arsenal because it shut down
and has not restarted its five megawatt electric plutonium production reactor. Although we
have seen no direct evidence of a highly enriched uranium (HEU) production program in
North Korea, judging from the available evidence, we think the next bomb test will be based
on HEU, or multiple bombs will be tested simultaneously, using both HEU and plutonium.109
On the other hand, a report of June 2013 indicated that North Korea was in the process of
restarting its plutonium reactor.110
If certain radioactive gases leak from the test quickly, are collected quickly by ground- or air-
based equipment, and are analyzed quickly, it may be possible to determine whether the device
used uranium or plutonium. This sequence must be performed within hours because, after that
time, radioactive decay prevents differentiating between the two materials. Even if such rapid
action is not possible, certain radioactive gases released from the test can travel thousands of
miles and can be analyzed by the IMS to confirm that an explosion is nuclear. This was done for
the 2006 test but not for the 2009 test, as the latter apparently did not vent radioactive material.
If particles of debris from the device vent into the atmosphere and are collected by equipment
operated by the IMS, the United States, or others, analysis of the debris can reveal considerable
information about the device, including whether it contained uranium or plutonium.111 The IMS,
for example, has three ground stations within 1,000 miles of the test site that can collect
radionuclides from the test,112 and the United States reportedly sent aircraft equipped with sensors

108 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “Update on CTBTO
Findings Related to the Announced Nuclear Test by North Korea,” February 15, 2013, http://www.ctbto.org/press-
centre/highlights/2013/update-on-ctbto-findings-related-to-the-announced-nuclear-test-by-north-korea/.
109 Frank Pabian and Siegfried Hecker, “Contemplating a Third Nuclear Test in North Korea,” Bulletin of the Atomic
Scientists
(online edition), August 6, 2012.
110 “Update on Yongbyon: Restart of Plutonium Production Reactor Nears Completion; Work Continues on the
Experimental Light Water Reactor,” by Jeffrey Lewis and Nick Hansen, 38 North, June 3, 2013, http://38north.org/
2013/06/yongbyon060313/.
111 The United States obtained such information by analyzing debris from the Soviet Union’s first atomic bomb test in
1949 and its first hydrogen bomb test in 1953. Richard Rhodes, Dark Sun: The Making of the Hydrogen Bomb (New
York: Simon & Schuster, 1995), pp. 371-372, 524-525.
112 For a map of IMS stations, go to http://www.ctbto.org/map/ and click on “International Monitoring System.”
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in an effort to collect such material.113 Whether the absence of venting in the 2009 test was due to
more careful sealing of the test shaft, better knowledge of test site geology, deeper burial of the
test device, luck, or some combination is not known; North Korea’s success in preventing venting
in 2009 plus additional study might make venting unlikely for the 2013 test. The 2013 test
apparently was of higher yield than the 2009 test, though the effect of somewhat higher yield on
venting is unclear; some argue that venting is more likely for a very low yield test because there
is less energy to melt rock, sealing the test cavity. Thorough analysis of debris collected, if any,
may take days or weeks. On February 15, the CTBTO stated that there were no signs of
radioactive release from the test, but that it was too soon to say whether the test had released any
radioactive material.114 However, between April 8 and 14, IMS stations detected radioactive
isotopes of xenon consistent with a North Korean test of February 12.115
North Korea’s nuclear program continues. Reports of 2014 and 2015 indicate construction at the
Yongbyon nuclear reactor site,116 including construction of a new reactor at Yongbyon that may
be able to produce enough plutonium for five to six warheads per year;117 construction at the
Sohae Satellite Launching Station;118 work to miniaturize nuclear warheads;119 and an alleged test
of a submarine-launched ballistic missile.120 However, a report of January 2015 indicated, based
on satellite imagery showing no signs of test preparation at the test site at Punggye-ri, that another
nuclear test did not appear imminent.121 As of June 2015, there have been no press reports of
another nuclear test.
For additional information on North Korea’s nuclear weapons program, see CRS Report
RL34256, North Korea’s Nuclear Weapons: Technical Issues, by Mary Beth D. Nikitin. For
information on systems and technology for monitoring nuclear tests, see CRS Report R41160,

113 David Sanger and Choe Sang-Hun, “North Korea Confirms It Conducted 3d Nuclear Test,” New York Times (online
edition), February 12, 2013.
114 Personal communication from Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, February 15,
2013.
115 Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission, “CTBTO detects radioactivity
consistent with 12 February announced North Korean nuclear test,” press release, April 23, 2013, http://www.ctbto.org/
press-centre/press-releases/2013/ctbto-detects-radioactivity-consistent-with-12-february-announced-north-korean-
nuclear-test/, and accompanying the foregoing source, Comprehensive Nuclear-Test-Ban Treaty Organization
Preparatory Commission, “Media questions / answers on radionuclide detection,” http://www.ctbto.org/the-treaty/
developments-after-1996/2013-dprk-announced-nuclear-test/media-questions-answers-on-radionuclide-detection/.
116 David Albright, Serena Kelleher-Vergantini, William Baker, and Won Gi You, “Activities Detected at North
Korea’s Yongbyon Nuclear Site,” Institute for Science and International Security, August 6, 2014, http://www.isis-
online.org/uploads/isis-reports/documents/Yongbyon_August_6_FINAL.pdf.
117 “New Reactor May Boost North Korea’s Warhead Production: Expert,” Global Security Newswire, July 7, 2014,
http://www.nti.org/gsn/article/expert-says-pyongyangs-fissile-material-production-capacity-could-rise-sharply-new-
reactor/.
118 Nick Hansen, “North Korea’s Sohae Facility: Preparations for Future Large Rocket Launches Progresses; New
Unidentified Buildings,” 38 North, July 29, 2014, http://38north.org/2014/07/sohae073014/.
119 Bruce Klingner, “Allies Should Confront Imminent North Korean Nuclear Threat,” Heritage Foundation
Backgrounder 2913, http://www.heritage.org/research/reports/2014/06/allies-should-confront-imminent-north-korean-
nuclear-threat.
120 Choe Sang-Hun, “North Korea Says It Test-Fired Missile From Submarine,” New York Times, May 8, 2015. But see
also Jeffrey Lewis, “DPRK SLBM Test,” Arms Control Wonk, May 13, 2015.
121 Jack Liu and Nick Hansen, “North Korea’s Punggye-ri Nuclear Test Site: No Sign of Test Preparations,” 38 North,
January 16, 2015, http://38north.org/2015/01/punggye0101615/.
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North Korea’s 2009 Nuclear Test: Containment, Monitoring, Implications, by Jonathan E.
Medalia. As of June 2015, North Korea had not signed the CTBT.
CTBT Negotiations, Provisions, Entry into Force
CTBT Negotiations and the Nuclear Nonproliferation Treaty
The Conference on Disarmament, or CD, calls itself “the sole multilateral disarmament
negotiating forum of the international community.” It is affiliated with, funded by, but
autonomous from the United Nations. It operates by consensus; each member state can block a
decision. On August 10, 1993, the CD gave its Ad Hoc Committee on a Nuclear Test Ban “a
mandate to negotiate a CTB.” On November 19, 1993, the United Nations General Assembly
unanimously approved a resolution calling for negotiation of a CTBT. The CD’s 1994 session
opened in Geneva on January 25, with negotiation of a CTBT its top priority.
The priority had to do with extension of the Nuclear Non-Proliferation Treaty (NPT).122 That
treaty entered into force in 1970. It divided the world into nuclear “haves”—the United States,
Soviet Union, Britain, France, and China, the five123 declared nuclear powers, which are also the
permanent five (“P5”) members of the U.N. Security Council—and nuclear “have-nots.” The P5
would be the only States Party to the NPT to have nuclear weapons, but they (and others) would
negotiate in good faith on halting the nuclear arms race soon, on nuclear disarmament, and on
general and complete disarmament. Nonnuclear weapon states saw attainment of a CTBT as the
touchstone of good faith on these matters. The NPT provided for reviews every five years; a
review in 1995, 25 years after it entered into force, would determine whether to extend the treaty
indefinitely or for one or more fixed periods. The Review and Extension Conference of April-
May 1995 extended the treaty indefinitely. Extension was accompanied by certain measures,
including a Decision on Principles and Objectives for Nuclear Non-Proliferation and
Disarmament that set forth goals on universality of the NPT, nuclear weapon free zones, etc., and
stressed the importance of completing “the negotiations on a universal and internationally and
effectively verifiable Comprehensive Nuclear-Test-Ban Treaty no later than 1996.”
The extension decision, binding on States Party to the NPT, was contentious. Nonnuclear States
Party argued that the P5 failed to meet their NPT obligations by not concluding a CTBT. They
saw progress on winding down the arms race as inadequate. They assailed the NPT as
discriminatory because it divides the world into nuclear and nonnuclear states, and argued for a
regime in which no nation has nuclear weapons. The CTBT, in their view, symbolized this regime
because, unlike the NPT, the P5 would give up something tangible, the ability to develop new
sophisticated warheads. Some nonnuclear states saw NPT extension as their last source of
leverage for a CTBT. Other nonnuclear states felt that the NPT was in the interests of all but
would-be proliferators, that anything less than indefinite extension would undermine the security
of most nations, and that the NPT was too important to put at risk as a means of pressuring the P5

122 For text of the treaty, see http://www.state.gov/t/isn/trty/16281.htm#treaty.
123 For detailed information on the CTBT negotiations, see Jaap Ramaker, Jenifer Mackby, Peter Marshall, and Robert
Geil, The Final Test: A History of the Comprehensive Nuclear-Test-Ban Treaty Negotiations, Vienna, Austria,
Provisional Technical Secretariat of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization, 2003, 291 p.
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for a CTBT. The explicit linkage finally drawn between CTBT and NPT lent urgency to
negotiations on the former.
The CD reached a draft treaty in August 1996. India argued that the CTBT “should be securely
anchored in the global disarmament context and be linked through treaty language to the
elimination of all nuclear weapons in a time bound framework.”124 India also wanted a treaty to
bar weapons research not involving nuclear tests. The draft treaty did not meet these conditions,
which the nuclear weapon states rejected, so India vetoed it at the CD on August 20, barring it
from going to the U.N. General Assembly as a CD document. As an alternate way to open the
treaty for signing, Australia on August 23 asked the General Assembly to consider a resolution to
adopt the draft CTBT text and for the Secretary-General to open it for signing so it could be
adopted by a simple majority, or by the two-thirds majority that India sought, avoiding the need
for consensus. A potential pitfall was that the resolution (the treaty text) was subject to
amendment, yet the nuclear weapon states viewed amendments as unacceptable. India did not
raise obstacles to the vote, which was held September 10, with 158 nations in favor, 3 against
(India, Bhutan, and Libya), 5 abstentions, and 19 not voting.
A sixth five-year NPT review conference was held April 24-May 19, 2000, in New York. U.S.
rejection of the CTBT, lack of Chinese ratification, U.S. efforts to seek renegotiation of the ABM
Treaty, and efforts to ban nuclear weapons in the Middle East led some to fear a dire outcome of
the conference. However, some contentious issues were ironed out or avoided, and concessions
were made. For example, a joint statement by the P5 to the conference on May 1 said, “No efforts
should be spared to make sure that the CTBT is a universal and internationally and effectively
verifiable treaty and to secure its earliest entry into force.”125 As a result of effort by many
nations, the final document of the conference was adopted by consensus. The document included
a 13-step Nuclear Disarmament Plan of Action, the first two elements of which called for the
early entry into force of the treaty and a moratorium on nuclear explosions pending entry into
force.
At the NPT Review Conference of May 2005, the CTBT was a point of contention. For example,
Alberto Romulo, Secretary of Foreign Affairs, Republic of the Philippines, said, “Plans to
develop new nuclear weapons technology and failure to bring the Comprehensive Test Ban Treaty
(CTBT) into force seriously erode the historic foundations of the NPT.”126 Ihor Dolhov, Deputy
Foreign Minister for Foreign Affairs of Ukraine, said, “Ukraine continues to underscore the
importance and urgency of an early entry into force of the Treaty and calls upon all States who
have not yet done so to adhere to the Treaty without delay and unconditionally.”127 Ambassador

124 India. Embassy. “Statement by Ms. Arundhati Ghose, Ambassador/Permanent Representative of India to UN,
Geneva, in the Plenary of the Conference on Disarmament on January 25, 1996,” at http://www.indianembassy.org/
policy/Disarmament/cd(jan2596).htm.
125 France. Embassy of France in the United States. “2000 Review Conference of the Parties to the Treaty on the Non-
Proliferation of Nuclear Weapons: Statement by the Delegations of France, The People’s Republic of China, The
Russian Federation, The United Kingdom of Great Britain and Northern Ireland and The United States of America,”
New York, May 1, 2000, at http://www.ambafrance-us.org/news/statmnts/2000/tnp5.asp.
126 Philippines. Mission to the United Nations. “Collective Action: Regional Responsibility and Global Accountability
Towards a World Free of Nuclear Weapons, Statement by H.E. Dr. Alberto G. Romulo, Secretary of Foreign Affairs,
Republic of the Philippines, at the General Debate of the 2005 Review Conference of the Nuclear Non-Proliferation
Treaty, New York, 11 May 2005,” p. 2, at http://www.un.org/events/npt2005/statements/npt11philippines.pdf.
127 Ukraine. Permanent Mission of Ukraine to the United Nations. “Statement by H.E. Mr. Ihor Dolhov, Deputy
Minister for Foreign Affairs of Ukraine, at the 2005 NPT Review Conference, New York, 5 May 2005,” p. 4, at
http://www.un.org/events/npt2005/statements/npt05ukraine.pdf.
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Ronaldo Sardenberg of Brazil said, “Brazil has consistently called for the universalization of the
CTBT, which we consider to be an essential element of the disarmament and non-proliferation
regime.”128
The eighth NPT review conference was held May 3-28, 2010, at U.N. headquarters in New York.
Many speakers supported the CTBT. Secretary of State Clinton said, “We have made a
commitment to ratify the Comprehensive Test Ban Treaty.”129 Indonesia’s Minister for Foreign
Affairs, R.M. Marty M. Natalegawa, announced, “Indonesia is initiating the process of the
ratification of the Comprehensive Nuclear Test Ban Treaty.”130 Indonesia is one of the remaining
nine nations that must ratify the CTBT for it to enter into force. (Indonesia subsequently
deposited its instruments of ratification with the United Nations on February 6, 2012,131 reducing
to eight the number of nations that must ratify the treaty for it to enter into force.) Natalegawa, in
a separate statement on behalf of the Non-Aligned Movement (NAM), said, “The NAM States
Parties [to the NPT] strongly urge this Review Conference to clearly and categorically reject the
policies of nuclear deterrence and place a ban on all forms of nuclear weapon testing with a view
to their total elimination.”132 A speaker representing the European Union identified “achieving
rapid entry into force of the CTBT” as an “indispensable [step] towards fulfillment of the
obligations and final objective enshrined in Article VI of the NPT.”133 The five original nuclear
weapon states declared,
We reaffirm our determination to abide by our respective moratoria on nuclear test
explosions before entry into force of the Comprehensive Nuclear-Test-Ban Treaty (CTBT)
and call on all States to refrain from conducting a nuclear test explosion. The moratoria,
though important, are not a substitute for legally binding commitments under the CTBT. We
will continue our efforts aimed at early entry into force of the CTBT and achieving its
universality and call upon all States that have not yet done so to sign and ratify this Treaty.134

128 Brazil. “VII Review Conference of Treaty on the Non-Proliferation of Nuclear Weapons, Statement by the Head of
the Delegation of Brazil, Ambassador Ronaldo Sardenberg, New York, 2 May 2005,” p. 4, at http://www.un.org/
events/npt2005/statements/npt04brazil.pdf.
129 The Delegation of the United States of America to the 2010 Review Conference of the Treaty on the Non-
Proliferation of Nuclear Weapons, 3-28 May 2010, “Statement by Secretary of State Hillary Rodham Clinton to the
2010 Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons,” general debate, New York, May
3, 2010, p. 6, http://www.un.org/en/conf/npt/2010/statements/pdf/usa_en.pdf.
130 Republic of Indonesia. Permanent Mission of the Republic of Indonesia to the United Nations. “Statement by H.E.
Dr. R.M. Marty M. Natalegawa, Minister for Foreign Affairs of the Republic of Indonesia at the General Debate of the
2010 NPT Review Conference,” New York, May 3, 2010, p. 2, http://www.un.org/en/conf/npt/2010/statements/pdf/
indonesia_en.pdf.
131 United Nations Office for Disarmament Affairs. “Indonesia Deposits Instrument of Ratification to the
Comprehensive Nuclear-Test-Ban Treaty,” February 6, 2012, http://www.un.org/disarmament/content/news/
indonesia_ctbt/.
132 “Statement by H.E. Dr. R.M. Marty M. Natalegawa, Minister for Foreign Affairs of the Republic of Indonesia, on
Behalf of the NAM States Party to the Non-Proliferation of Nuclear Weapons Treaty (NPT), before the 2010 Review
Conference of the Parties to the Non-Proliferation of Nuclear Weapons Treaty,” May 3, 2010, p. 3, http://www.un.org/
en/conf/npt/2010/statements/pdf/nam_en.pdf.
133 “Statement on Behalf of the European Union by H.E. Catherine Ashton, High Representative of the European Union
for Foreign Affairs and Security Policy at the General Debate of the Review Conference of the Treaty on the Non-
Proliferation of Nuclear Weapons (NPT),” United Nations, New York, May 3, 2010, p. 5, http://www.un.org/en/conf/
npt/2010/statements/pdf/eu_en.pdf.
134 “Statement by the People’s Republic of China, France, the Russian Federation, the United Kingdom of Great Britain
and Northern Ireland, and the United States of America to the 2010 Non-Proliferation Treaty Review Conference,”
May 5, 2010, p. 2, http://www.un.org/en/conf/npt/2010/statements/pdf/russia5_en.pdf.
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In its final document, “the Conference reaffirms the vital importance of the entry into force of the
Comprehensive Nuclear-Test-Ban Treaty as a core element of the international nuclear
disarmament and non-proliferation regime,” and resolved that “all nuclear-weapon States
undertake to ratify the Comprehensive Nuclear-Test-Ban Treaty with all expediency.”135
The ninth NPT Review Conference was held April 27–May 22, 2015. Several preparatory
committee sessions are held prior to each review conference. The first session for the ninth
review conference was held April 30-May 11, 2012, in Vienna; the second, April 22-May 3, 2013,
in Geneva; and the third, April 28-May 9, 2014, in New York.136 Among other things, delegates
called for entry into force of the CTBT and referenced the final document of the 2010 review
conference. In particular, a working paper submitted to the 2012 session stated,
The Vienna Group of Ten firmly believes that the Comprehensive Nuclear-Test-Ban Treaty
constitutes an effective measure of nuclear disarmament and nuclear non-proliferation in all
its aspects and is vital to the Treaty on the Non-Proliferation of Nuclear Weapons. The Test-
Ban Treaty was an integral part of the 1995 decision to indefinitely extend the Non-
Proliferation Treaty. The Group therefore stresses that the entry into force of the Test-Ban
Treaty is of the utmost urgency and recalls that the 2000 and 2010 Review Conferences of
the Parties to the Non-Proliferation Treaty reaffirmed the vital importance of the entry into
force of the Test-Ban Treaty, with the action plan from the 2010 Review Conference again
emphasizing the resolve of States parties to the Non-Proliferation Treaty to achieve that aim.
The Group reaffirms that the provisions of article V of the Non-Proliferation Treaty are to be
interpreted in the light of the Test-Ban Treaty.137
At the conference, over 100 states made statements supportive of the CTBT or urging that it be
brought into force.138 As one example, the representative of the Marshall Islands said, “We should
further affirm that the Test Ban Treaty is vital to the NPT, recognizing that its entry into force is
essential. The Marshall Islands’ own direct experience [with nuclear testing] should be lesson
enough for the world to firmly commit to ending nuclear testing.”139 The conference failed to
produce a final document. The main obstacle was not the CTBT, but a lack of consensus over
ways to achieve a Middle East nuclear weapons-free zone. This outcome angered many
nations.140 Instead, the outcome of the conference was adoption of a Humanitarian Pledge in

135 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, Final
Document,
Volume I, NPT/CONF010/50 (Vol. I), p. 22, http://www.un.org/ga/search/view_doc.asp?symbol=NPT/
CONF.2010/50%20(VOL.I).
136 The website “NPT Review Conferences and Preparatory Committees” of the United Nations Office for
Disarmament Affairs, http://www.un.org/disarmament/WMD/Nuclear/NPT_Review_Conferences.shtml, has links to
the preparatory committee meetings; these links, in turn, have links to documents from each meeting, including
speeches by representatives of nations and groups of nations.
137 Preparatory Committee for the 2015 Review Conference of the Parties to the Treaty on the Non-Proliferation of
Nuclear Weapons, “Comprehensive Nuclear-Test-Ban Treaty,” Working paper submitted by Australia, Austria,
Canada, Denmark, Finland, Hungary, Ireland, the Netherlands, New Zealand, Norway and Sweden (the Vienna Group
of Ten), March 16, 2012, NPT/CONF.2015/PC.I/WP.4, http://www.un.org/ga/search/view_doc.asp?symbol=NPT/
CONF.2015/1.
138 Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission, “Statements on the CTBT,” c.
May 4, 2015, http://www.ctbto.org/specials/npt-revcon-2015/statements-on-the-ctbt/.
139 Republic of the Marshall Islands. Permanent Mission to the United Nations. Hon. Mr. Tony deBrum, Minister of
Foreign Affairs, address to 9th Review Conference of the States Parties to the Treaty on Non-Proliferation of Nuclear
Weapons, General Debate, April 27, 2015, http://www.un.org/en/conf/npt/2015/statements/pdf/MH_en.pdf.
140 United Nations. “Consensus Eludes Nuclear Non-Proliferation Treaty Review Conference as Positions Harden on
Ways to Free Middle East of Mass Destruction Weapons,” press release, May 22, 2015, http://www.un.org/press/en/
2015/dc3561.doc.htm.
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which signatories pledged, among other things, “to cooperate with all relevant stakeholders ... in
efforts to stigmatise, prohibit and eliminate nuclear weapons in light of their unacceptable
humanitarian consequences and associated risks.”141 As of June 1, 2015, 108 nations had
endorsed or otherwise expressed their support for this pledge.142
Key Provisions of the CTBT
Scope (Article I): The heart of the treaty is the obligation “not to carry out any nuclear weapon
test explosion or any other nuclear explosion.” This formulation bars even very low yield tests
that some in the nuclear weapon states had wanted, and bars peaceful nuclear explosions that
China had wanted, but rejects India’s concern that a CTBT should “leave no loophole for activity,
either explosive based or non-explosive based, aimed at the continued development and
refinement of nuclear weapons.”143 Views differ on whether the ban covers tests with the tiniest
nuclear yield. Opponents of the treaty argue that the treaty “fails to define what it purports to
prohibit,” that is, a “nuclear test,” that Russia considers hydronuclear tests (those producing
grams to hundreds of pounds of nuclear yield) as permissible, and that Russia has conducted such
tests. Further, it is argued, tests with very low nuclear yields could not be detected using current
technologies.144 Supporters respond that the negotiating record makes clear that Russia agreed
that “experiments which do produce a nuclear yield ... would be banned.”145 According to the
State Department, the CTBT
prohibits all nuclear explosions that produce a self-sustaining, supercritical chain reaction of
any kind … The decision not to include a specific definition of scope in the Treaty was a
deliberate decision by the negotiating parties, including the United States, made to ensure
that no loopholes were created by including a highly technical and specific list of what
specific activities were and were not permitted under the Treaty. A thorough review of the
history of the Treaty negotiation process, as well as statements by world leaders and the
negotiators of the agreement, shows that all states understand and accept the CTBT as a
“zero-yield” treaty.146
Organization (Article II): The treaty establishes a Comprehensive Nuclear-Test-Ban Treaty
Organization (CTBTO), composed of all member states, to implement the treaty.147 Three groups
are under the CTBTO. The Conference of States Parties, composed of a representative from each
member state, shall meet in annual and special sessions to consider and decide issues within the

141 Austria, “Humanitarian Pledge,” c. 2015, p. 2, http://www.bmeia.gv.at/fileadmin/user_upload/Zentrale/
Aussenpolitik/Abruestung/HINW14/HINW14vienna_Pledge_Document.pdf.
142 Republic of Austria, Federal Ministry, Vienna Conference on the Humanitarian Impact of Nuclear Weapons, 8-9
December 2014, endorsements or expressions of support for the Humanitarian Pledge, update of May 26, 2015,
http://www.bmeia.gv.at/fileadmin/user_upload/Zentrale/Aussenpolitik/Abruestung/HINW14/
HINW14vienna_update_pledge_support.pdf. This website updates the list of supporters from time to time.
143 India, “Statement by Ms. Arundhati Ghose, ... January 25, 1996.”
144 Kathleen Bailey and Thomas Scheber, The Comprehensive Test Ban Treaty: An Assessment of the Benefits, Costs,
and Risks
, National Institute for Public Policy, March 2011, pp. 15-16.
145 U.S. Congress, Senate Committee on Foreign Relations, Final Review of the Comprehensive Nuclear Test Ban
Treaty
, Hearing on Treaty Doc. 105-28, 106th Cong., 1st sess., October 7, 1999, S.Hrg. 106-262 (Washington: GPO,
2000), pp. 16-17, testimony of Stephen Ledogar, former chief negotiator of the Comprehensive Test Ban Treaty.
146 U.S. Department of State. “Scope of the CTBT,” fact sheet, 1 p., September 29, 2011, http://www.state.gov/t/avc/
rls/173944.htm.
147 For further information on the CTBTO, see its website at http://www.ctbto.org.
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scope of the treaty and oversee the work of the other groups. An Executive Council with 51
member states shall, among other things, act on requests for on-site inspection, and may request a
special session of the Conference. A Technical Secretariat shall carry out verification functions,
including operating an International Data Center (IDC), processing and reporting on data from an
International Monitoring System, and receiving and processing requests for on-site inspections.
Verification (Article IV): The treaty establishes a verification regime. It provides for collection
and dissemination of information, permits States Party to use national technical means of
verification, and specifies verification responsibilities of the Technical Secretariat. It establishes
an International Monitoring System (IMS) and provides for on-site inspections. The treaty calls
for the IMS to have, when complete, 321 stations worldwide to monitor signatures that might
indicate a nuclear explosion: 170 seismic stations to monitor seismic waves in the Earth; 11
hydroacoustic stations to monitor underwater sound waves; 60 arrays of infrasound detectors to
monitor very low frequency sound waves in the atmosphere; and 80 radionuclide stations to
detect radioactive particles and (for half the stations) radioactive xenon gas that a nuclear
explosion might produce, as well as 16 radionuclide laboratories to analyze radioactive samples.
Of the seismic stations, 50 are to be primary stations to provide data to IDC continuously and in
real time, while 120 are to be auxiliary stations to provide data when requested by the IDC. As of
June 2015, of the 337 facilities, 18 were planned, 19 were under construction, 19 were installed
but not yet certified, and 281 had been certified, that is, they were completed and met the
technical requirements of the Preparatory Commission.148 Certified stations transmit data
automatically and continuously to the IDC, excepting for the auxiliary stations and the
radionuclide laboratories, which transmit data as requested by the IDC.149 In March 2008, the
Preparatory Commission launched the International Scientific Studies (ISS) Project. A conference
to report the results was held in Vienna, Austria, on June 10-12, 2009.150 “The ISS aim is to foster
the CTBTO Preparatory Commission’s ability to keep pace with scientific and technological
progress and to strengthen cooperation between the organization and the scientific community.”151
Critics would note that a focus on progress implies less focus on possible difficulties. The second
conference in this series was held June 8-10, 2011, and the third was held June 17-21, 2013, both
in Vienna.152 The fourth is to be held June 22-26, 2015, also in Vienna.153
In September 2008, the PrepCom conducted its large-scale Integrated Field Exercise 2008 in
Kazakhstan to simulate a complete on-site inspection.154 The PrepCom called the exercise a

148 The CTBTO Preparatory Commission provides updated information on the status of these facilities on its home
page, http://www.ctbto.org/.
149 Information provided by Annika Thunborg, Chief, Public Information, Comprehensive Nuclear-Test-Ban Treaty
Preparatory Commission, personal communication, November 26, 2007.
150 For links to publications of the conference, see “ISS09, International Scientific Studies,” http://www.ctbto.org/
specials/the-international-scientific-studies-project-iss/.
151 ISS09—International Scientific Studies, “International Scientific Studies Conference, Vienna, 10-12 June 2009,”
p. 1.
152 Documents from, and about, these conferences are available on the CTBTO Preparatory Commission website at
http://www.ctbto.org/the-organization/science-and-technology-the-conference-series/.
153 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “CTBT: Science and
Technology 2015,” http://www.ctbto.org/specials/snt2015/.
154 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “CTBTO Inspectors
Implement On-site Inspection Test Scenario in Kazakh Steppe,” press release, September 12, 2008, at
http://www.ctbto.org/press-centre/highlights/2008/ctbto-inspectors-implement-on-siteinspection-test-scenario-in-
kazakh-steppe/12-september-2008-page-1/.
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success.155 In November 2010, the PrepCom held a simulated on-site inspection in Jordan to
improve capability to detect evidence of clandestine testing.156 157 On October 24, 2011, the
PrepCom endorsed a budget of $10.3 million for an integrated field exercise in 2014.158 This
exercise was held in Jordan from November 3 to December 9, 2014. It was intended to “to
simulate an almost entire on-site inspection ... the inspection team will conduct a meticulous
search of a clearly defined inspection area to establish whether or not a nuclear explosion has
been conducted. The exercise will be in response to a technically realistic and stimulating but
fictional scenario.”159 During the exercise, “the inspection team searched an inspection area of
nearly 1,000 square kilometres using 15 of the 17 techniques permissible under the [CTBT].
Some of these state-of-the-art techniques were used for the first time in an on-site inspection
context.... Throughout the inspection, the team narrowed down the regions of interest to one
limited area where relevant features including traces of relevant radionuclides were successfully
found.” The CTBTO PrepCom called the exercise a success.160
A concern for the IMS is the release into the atmosphere of radioactive isotopes of xenon
(“radioxenons”) as byproducts of production of radionuclides in nuclear reactors. A particular
concern is the production of molybdenum-99 (Mo-99), which is used extensively for medical
tests and treatment. Radioxenons are of use in detecting nuclear explosions because they are
noble gases, which do not form chemical compounds in nature. As such, they may seep to the
surface of the Earth, where they can be transported by wind. Sensitive instruments can detect
trace quantities of radioxenons thousands of miles away; indeed, in October 2006, an IMS station
in Yellowknife, Canada, detected radioxenons that were apparently from the first North Korean
nuclear test, more than 7,000 km distant.161
Since Mo-99 has a short half-life, 65.9 hours, it must be continuously produced. As it happens,
“Mo-99 production emissions from a specific type of production process can interfere with these
[IMS] sensors, complicating the ability of the monitoring networks to detect a nuclear
explosion.”162 To reduce the potential for interference, CTBTO, NNSA, and many others have

155 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, “Integrated Field Exercise 2008
Concludes Successfully,” http://www.ctbto.org/press-centre/highlights/2008/integrated-field-exercise-2008concludes-
successfully/8-october-2008-page-1/.
156 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, “Exercise to Inspect a Simulated Nuclear
Test Site—Jordan, 1 to 12 November 2010,” press release, November 1, 2010, http://www.ctbto.org/press-centre/press-
releases/2010/exercise-to-inspect-a-simulated-nuclear-test-site-jordan-1-to-12-november-2010/.
157 For a detailed technical discussion of CTBT monitoring and verification, see Ola Dahlman, Jenifer Mackby, Svein
Mykkeltveit, and Hein Haak, Detect and Deter: Can Countries Verify the Nuclear Test Ban?, Dordrecht, Netherlands,
Springer, 2011. For a countervailing view, see Kathleen Bailey and Thomas Scheber, The Comprehensive Test Ban
Treaty: An Assessment of the Benefits, Costs, and Risks,
Fairfax, VA, National Institute Press, 2011, pp. 17-23.
158 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “CTBTO Member States
Take Test-Ban Verification to the Next Level,” press release, October 24, 2011, http://www.ctbto.org/press-centre/
press-releases/2011/ctbto-member-states-take-test-ban-verification-to-the-next-level/.
159 “IFE14,” http://www.ctbto.org/specials/integrated-field-exercise-2014/.
160 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, “Largest-Ever CTBT On-Site Inspection
Exercise Concludes Successfully,” December 9, 2014, http://www.ctbto.org/press-centre/press-releases/2014/largest-
ever-ctbt-on-site-inspection-exercise-concludes-successfully/.
161 P.R.J. Saey et al., “A Long Distance Measurement of Radioxenon in Yellowknife, Canada, in Late October 2006,”
Geophysical Research Letters, vol. 34 (2007), http://onlinelibrary.wiley.com/doi/10.1029/2007GL030611/pdf.
162 National Nuclear Security Administration, “NNSA Contributes to International Efforts to Further Strengthen
Detection of Nuclear Explosions,” May 15, 2015, http://www.nnsa.energy.gov/blog/nnsa-contributes-international-
efforts-further-strengthen-detection-nuclear-explosions.
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pressed for ways to reduce radioxenon emissions from production of Mo-99 and other medical
radionuclides. Steps taken since 2013 include:
• Several producers of medical radionuclides have signed a pledge under which,
among other things, they will minimize, to the extent practicable, emissions of
such radionuclides, and share data on xenon emissions with the CTBTO, while
the latter will help producers clarify concerns due to elevated radioxenon
readings at IMS monitoring stations.163
• The P5 issued a statement on this topic in connection with the 2015 NPT Review
Conference that included the following: “The P5 believe that all States should
engage with producers in their regions to assess the amount of emissions and to
reduce where it is possible their negative impact on the environment through
minimization of emissions from fission-based medical isotope production.”164
• The CTBTO, Pacific Northwest National Laboratory, and SCK-CEN Belgian
Nuclear Research Centre held a Workshop on Signatures of Medical and
Industrial Isotope Production in May 2015 to discuss ways that producers of
medical isotopes could reduce radioxenon emissions.165
Review of the Treaty (Article VIII): The treaty provides for a conference 10 years after entry into
force (unless a majority of States Party decide not to hold such a conference) to review the
treaty’s operation and effectiveness. Further review conferences may be held at subsequent
intervals of 10 years or less. The treaty had not entered into force as of June 2015, so no Article
VIII conference has been held.
Duration and Withdrawal (Article IX): “This treaty shall be of unlimited duration.” However,
“Each State Party shall, in exercising its national sovereignty, have the right to withdraw from this
Treaty if it decides that extraordinary events related to the subject matter of this Treaty have
jeopardized its supreme interests.” President Clinton indicated his possible willingness to
withdraw from the Treaty using this withdrawal provision, which is common to many arms
control agreements, in his speech of August 11, 1995, discussed below, as one of several
conditions under which the United States would enter the CTBT.
Entry Into Force (Article XIV): The treaty shall enter into force 180 days after 44 states named
in Annex 2 have deposited instruments of ratification, but not less than two years after the treaty
is opened for signature. The 44 states are those with nuclear reactors that participated in the work
of the CD’s 1996 session and were CD members as of June 18, 1996. This formulation includes
nuclear-capable states and nuclear threshold states (in particular Israel, which, along with other
States, joined the CD on June 17, 1996), and excludes the former Yugoslavia. Of the 44, as of
June 2015, India, North Korea, and Pakistan had not signed the treaty and China, Egypt, Iran,
Israel, and the United States had signed but not ratified it.

163 CTBTO, “Breakthrough in mitigating radioxenon emissions,” November 13, 2013, http://www.ctbto.org/press-
centre/press-releases/2013/breakthrough-in-mitigating-radioxenon-emissions/.
164 U.S. Department of State. Office of the Spokesperson. “Joint P5 Statement for 2015 Non-Proliferation Treaty
Review Conference on Minimizing the Impact of Medical Isotope Production on the Release of Xenon Gas Into the
Environment,” March 2, 2015, http://www.state.gov/r/pa/prs/ps/2015/03/238101.htm.
165 CTBTO, “Mitigating Effects of Xenon Emissions,” May 15, 2015, http://www.ctbto.org/press-centre/highlights/
2015/mitigating-effects-of-xenon-emissions/.
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If the treaty has not entered into force three years after being opened for signature, and if a
majority of states that have deposited instruments of ratification so desire, a conference of these
states shall be held to decide how to accelerate ratification. Unless otherwise decided, subsequent
conferences of this type shall be held annually until entry into force occurs. In practice, these
conferences (often called Article XIV conferences) have been held every second year beginning
in 1999. The CTBTO PrepCom serves as the secretariat of these conferences.
In a message to the third conference, in 2003, U.N. Secretary-General Kofi Annan urged the
nations that had to ratify the treaty for it to enter into force, and especially North Korea, to ratify,
and urged continuing the moratorium: “No nuclear testing must be tolerated under any
circumstances.”166
The sixth Article XIV conference was held September 24-25, 2009, at U.N. headquarters in New
York; Secretary of State Hillary Rodham Clinton, among others, delivered remarks at the
conference. The final declaration of the 2009 conference stated, “Relevant international
developments since the 2007 Conference on Facilitating the Entry into Force of the CTBT make
entry into force of the Treaty more urgent today than ever before,” and adopted 10 measures to
promote entry into force.167
The seventh conference was held September 23, 2011, at U.N. headquarters in New York. At this
conference, Ellen Tauscher, Under Secretary of State for Arms Control and International Security,
said that one of the highest priorities of the Obama Administration is ratification and entry into
force of the treaty, that the United States was providing $34.4 million to the Comprehensive
Nuclear-Test-Ban Treaty Organization Preparatory Commission beyond the assessed contribution,
and that “we have begun the process of engaging the Senate,” though with “no set timeframes.”168
The final declaration of the 2011 conference emphasized the importance of early entry into force
of the treaty, called the ending of nuclear weapons testing “a meaningful step in the realization of
the goal of eliminating nuclear weapons globally,” and set forth 10 “concrete steps towards early
entry into force,” including encouraging the organization of regional seminars to increase
awareness of the importance of the treaty, providing states with legal assistance regarding the
ratification process, and encouraging cooperation with intergovernmental organizations,
nongovernmental organizations, and others to raise awareness of and support for the treaty.169
The eighth conference was held September 27, 2013, at U.N. Headquarters in New York.170 The
final declaration “affirm[ed] the importance and urgency of achieving early entry into force of the

166 U.N. “No Nuclear Testing Must Be Tolerated under Any Circumstances.” Press Release SG/SM/8843, DC/2885,
September 3, 2003, at http://www.un.org/News/Press/docs/2003/sgsm8843.doc.htm.
167 “Annex: Final Declaration and Measures to Promote the Entry into Force of the Comprehensive Nuclear-Test-Ban
Treaty,” in Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty, New York,
24-25 September 2009, “Report of the Conference,” CTBT-Art. XIV/2009/6, October 8, 2009, http://www.ctbto.org/
fileadmin/user_upload/Art_14_2009/CTBT-Art.XIV-2009-6.pdf.
168 U.S. Department of State. Ellen Tauscher, Under Secretary for Arms Control and International Security, remarks at
CTBT Article XIV Conference, New York, NY, September 23, 2011.
169 Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty, “Final Declaration
and Measures to Promote the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty,” New York, September
23, 2011, http://www.ctbto.org/fileadmin/user_upload/Art_14_2011/23-09-11/Final_Declaration.pdf.
170 Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty, 27 September
2013, United Nations, New York, USA, http://www.ctbto.org/the-treaty/article-xiv-conferences/2013-conference-on-
facilitating-the-entry-into-force-of-the-comprehensive-nuclear-test-ban-treaty-united-nations-new-york-usa/. This
website provides links to many documents from the conference.
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Treaty as a crucial practical step for systematic and progressive efforts towards nuclear
disarmament and nuclear non-proliferation,” “reaffirm[ed] our strong belief that it is essential to
maintain momentum in building all elements of the verification regime, which will be capable of
verifying compliance with the Treaty at its entry into force,” and adopted 11 “concrete steps
towards early entry into force and universalization of the Treaty.”171 It called upon the eight states
whose ratification is necessary for the CTBT to enter into force to ratify the treaty “at the earliest
possible date.”172
The ninth conference is scheduled for September 29, 2015, at U.N. Headquarters in New York.
Annexes: Annex 1 lists the regional groupings of states; Annex 2 lists the 44 states that must
ratify the treaty, pursuant to Article XIV, for it to enter into force.
Protocol: The Protocol provides details on the IMS and on functions of the International Data
Center (Part I); spells out on-site inspection procedures in great detail (Part II); and provides for
certain confidence-building measures (Part III). Annex 1 to the Protocol lists International
Monitoring System facilities: seismic stations, radionuclide stations and laboratories,
hydroacoustic stations, and infrasound stations. Annex 2 to the Protocol provides a list of
variables that, among others, may be used in analyzing data from these stations to screen for
possible explosions.
International Efforts on Behalf of Entry into Force
Article II of the CTBT establishes the Comprehensive Nuclear-Test-Ban Treaty Organization
(CTBTO). However, that organization will not come into existence until and unless the treaty
enters into force. As an interim measure, on November 29, 1996, states that had signed the treaty
adopted a resolution establishing the Preparatory Commission (PrepCom) for the CTBTO “for the
purpose of carrying out the necessary preparations for the effective implementation of the
Comprehensive Nuclear-Test-Ban Treaty, and for preparing for the first session of the Conference
of the States Parties to that Treaty.”173 The PrepCom held 43 meetings from 1996 through 2014;
meetings for 2015 are scheduled for June 18-19, and November 16-18. Eight meetings of working
groups and advisory groups were held or are scheduled for 2015.174 The PrepCom holds training
sessions and workshops, with over a dozen planned for 2015.175 The PrepCom offers educational
resources, including “iTunes University,” which enables users to download briefings and other
material on the CTBT, and the CTBT public policy course, “Verification Through Diplomacy and

171 Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty, New York, 27
September 2013, “Final Declaration and Measures to Promote the Entry into Force of the Comprehensive Nuclear-
Test-Ban Treaty,” http://www.ctbto.org/fileadmin/user_upload/Art_14_2013/Statements/Final_Declaration.pdf.
172 Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty, New York, 27
September 2013, “Final Declaration and Measures to Promote the Entry into Force of the Comprehensive Nuclear-
Test-Ban Treaty,” http://www.ctbto.org/fileadmin/user_upload/Art_14_2013/Statements/Final_Declaration.pdf.
173 “Resolution Establishing the Preparatory Commission for the Comprehensive Nuclear Test-Ban Treaty
Organization,” Adopted by the States Signatories, November 19, 1996: “Annex—Text on the Establishment of a
Preparatory Commission for the Comprehensive Nuclear Test-Ban Treaty Organization,” paragraph 1,
http://www.fas.org/nuke/control/ctbt/text/ctbt4.htm.
174 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “Calendar of Events,”
http://www.ctbto.org/the-organization/calendar-of-events/.
175 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “Workshops, Training and
Exercises,” http://www.ctbto.org/the-organization/workshops-training-and-exercises/.
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Science.”176 The PrepCom has scheduled a CTBT Science and Technology Conference from June
22 to 26, 2015.177
In addition to Article XIV conferences, there have been other calls for entry into force. For
example, in September of years between Article XIV conferences, foreign ministers of nations
that strongly support the CTBT meet on the margins of the U.N. General Assembly. According to
the CTBTO PrepCom, “The aim of these meetings is to sustain and generate further political
momentum as well as public attention for the entry into force of the Treaty. To that end, the
Ministers adopt and sign Joint Ministerial Statements that are open for adherence by other
countries.”178 At the first such meeting, in September 2002, a statement by 18 foreign ministers,
including those of Britain, France, and Russia, called for early entry into force. There have also
been U.N. resolutions on the CTBT. On November 22, 2002, the U.N. General Assembly adopted
resolution 57/100 (164 for, 1 against [United States], 5 abstentions) urging states to maintain their
nuclear test moratoria and urging states that had not signed and ratified the CTBT to do so as
soon as possible and to avoid actions that would defeat its object and purpose. These and other
efforts continue, as noted below.
A conference of the Non-Aligned Movement, which has 116 members, ended on February 25,
2003. Its Final Document stated that the heads of state or government “stressed the significance
of achieving universal adherence to the Comprehensive Nuclear-Test-Ban Treaty (CTBT),
including by all the Nuclear Weapons States.”179 On September 23, 2004, foreign ministers from
42 nations called for prompt ratification of the CTBT, especially by nations whose ratification is
required for entry into force.180 The Weapons of Mass Destruction Commission, an international
commission organized by Sweden, issued a report in June 2006 that, among other things, urged
all states that have not done so to sign and ratify the CTBT “unconditionally and without delay.”
It recommended that the 2007 conference of CTBT signatories “should address the possibility of
a provisional entry into force of the treaty.” It stated, “The Commission believes that a U.S.
decision to ratify the CTBT would strongly influence other countries to follow suit. It would
decisively improve the chances for entry into force of the treaty and would have more positive
ramifications for arms control and disarmament than any other single measure.”181 In September
2006, to mark the 10th anniversary of the CTBT’s opening for signature, 59 foreign ministers
issued a joint statement on the treaty that “[calls] upon all States that have not yet done so to sign
and ratify the Treaty without delay, in particular those whose ratification is needed for its entry
into force.”182

176 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “CTBT Educational
Resources,” http://www.ctbto.org/specials/ctbt-educational-resources/.
177 The conference website is http://www.ctbto.org/specials/snt2015/.
178 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “CTBT Ministerial
Meetings,” http://www.ctbto.org/the-treaty/ctbt-ministerial-meetings/.
179 Non-Aligned Movement, Kuala Lumpur Summit, February 20-25, 2003, “Non-Aligned Movement Conference Stresses
Importance of CTBT,” at http://pws.ctbto.org/press_centre/featured_articles/250203_nam.html.
180 Japan. Ministry of Foreign Affairs. “Joint Ministerial Statement on the CTBT,” New York, September 23, 2004,
http://www.mofa.go.jp/policy/un/disarmament/ctbt/joint0409.html.
181 Weapons of Mass Destruction Commission, Weapons of Terror: Freeing the World of Nuclear, Biological and
Chemical Arms.
June 2006, p. 107, 108, at http://www.wmdcommission.org/files/Weapons_of_Terror.pdf.
182 “Joint Ministerial Statement on the CTBT,” New York, September 20, 2006, at http://www.armscontrol.org/pdf/
20060920_CTBT_Joint_Ministerial_Statement.pdf#search=
%22%20%22joint%20ministerial%20statement%20on%20the%20ctbt%22%22.
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In January 2007, George Shultz, William Perry, Henry Kissinger, and Sam Nunn urged the United
States to work toward a world without nuclear weapons, with one step “Initiating a bipartisan
process with the Senate, including understandings to increase confidence and provide for periodic
review, to achieve ratification of the Comprehensive Test Ban Treaty, taking advantage of recent
technical advances, and working to secure ratification by other key states.”183 In response, a few
weeks later, Mikhail Gorbachev called on nuclear weapon states to ratify the CTBT, among other
actions.184 On November 19, former Secretary of Defense Harold Brown and former Director of
Central Intelligence John Deutch suggested a five-year renewable CTBT in lieu of the current
treaty.185 In January 2008, Shultz, Perry, Kissinger, and Nunn renewed their call for, among other
things, “a process for bringing the [CTBT] into effect” and called IMS “an effort the U.S. should
urgently support even prior to [CTBT] ratification.”186 In Senate testimony of April 2008,
Siegfried Hecker, former Director of Los Alamos National Laboratory, stated that without nuclear
tests, “slowly our confidence [in U.S. nuclear weapons] zeroes,” but that resumed U.S. testing
runs the risk that other nations would resume testing. “And as I personally today weigh those
risks, I definitely come out in favor that it’s in our nation’s and the world’s interest to actually
ratify the Comprehensive Test Ban Treaty.”187 On April 30, 2011, foreign ministers from 10
nations stated, “We call on all States which have not yet done so to sign and ratify the CTBT....
We believe that an effective end to nuclear testing will enhance and not weaken our national as
well as global security and would significantly bolster the global non-proliferation and
disarmament regime.”188 “To ensure an innovative and focused approach to advance the CTBT’s
ratification by the remaining Annex 2 States, a group comprising eminent personalities and
internationally recognized experts was launched on 26 September 2013 at the United Nations
Headquarters in New York.”189 This group issued a statement in April 2014 that said, among other
things, “The GEM [Group of Eminent Persons] discussed thoroughly the need for entry into force
of the CTBT in order to complete a global, legally-binding prohibition on nuclear weapon test
explosions or other nuclear explosions. The Group also noted that entry into force and
universalization of the CTBT would strengthen international disarmament efforts and the nuclear
non-proliferation regime.”190

183 George Shultz, William Perry, Henry Kissinger, and Sam Nunn, “A World Free of Nuclear Weapons,” Wall Street
Journal,
January 4, 2007, p. 15.
184 Mikhail Gorbachev, “The Nuclear Threat,” Wall Street Journal, January 31, 2007, p. 13.
185 Harold Brown and John Deutch, “The Nuclear Disarmament Fantasy,” Wall Street Journal, November 19, 2007, p.
19.
186 George Shultz, William Perry, Henry Kissinger, and Sam Nunn, “Toward a Nuclear-Free World,” Wall Street
Journal,
January 16, 2008, p. 13.
187 Testimony of Siegfried Hecker, former Director, Los Alamos National Laboratory, in U.S. Congress. Senate.
Committee on Appropriations. Subcommittee on Energy and Water Development. Hearing on the Department of
Energy and the U.S. Nuclear Weapon Non-Proliferation Efforts, 110th Congress, 2nd Session, April 30, 2008. Transcript
by CQ Transcriptions.
188 Australia. Department of Foreign Affairs and Trade. “Berlin Statement by Foreign Ministers on Nuclear
Disarmament and Non-Proliferation,” Berlin, April 30, 2011, http://www.dfat.gov.au/security/
berlin_statement_110430.html. The statement is by foreign ministers of Australia, Canada, Chile, Germany, Japan,
Mexico, the Netherlands, Poland, Turkey, and the United Arab Emirates.
189 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “Group of Eminent Persons
(GEM),” http://www.ctbto.org/the-treaty/article-xiv-conferences/2013-conference-on-facilitating-the-entry-into-force-
of-the-comprehensive-nuclear-test-ban-treaty-united-nations-new-york-usa/group-of-eminent-persons-gem/.
190 “Statement by the Group of Eminent Persons, Stockholm Meeting, 10-11 April 2014,” http://www.ctbto.org/
fileadmin/user_upload/public_information/2014/Statement_of_GEM_Stockholm_FINAL.pdf.
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The first Preparatory Committee meeting for the 2010 NPT Review Conference was held in
Vienna, Austria, in April and May 2007. The chair of the committee released a paper that stated,
“Strong support was expressed for the CTBT. The importance and urgency of its early entry into
force was underscored. States which had not ratified the Treaty, especially those remaining 10
States whose ratification was necessary for its entry into force, were urged to do so without delay
and without conditions.”191 A representative of Germany, speaking on behalf of the European
Union, said, “The EU reiterates its call on States, particularly those listed in Annex II, to sign and
ratify the said Treaty without delay and without conditions and, pending its entry into force to
abide by a moratorium on nuclear testing and to refrain from any action contrary to the
obligations and provisions of the CTBT.”192 The second Preparatory Committee meeting was held
in Geneva in April and May 2008. At the meeting, several dozen states made statements in
support of the CTBT and its entry into force.193 The conference was held May 3-28, 2010; as
noted earlier, many at the conference called for the CTBT to enter into force.
On September 24, 2008, the fourth CTBT Ministerial Meeting was held at U.N. headquarters; 96
nations signed a statement calling for signing and ratifying the treaty without delay and for
continuation of the nuclear testing moratorium.194 On December 2, 2008, the U.N. General
Assembly adopted a resolution (document A/63/395) urging states to sign and ratify the CTBT;
the vote was 175 in favor, 1 against (United States), and 3 abstentions (India, Mauritius, Syria).195
In December 2008, the American Association for the Advancement of Science, the American
Physical Society, and the Center for Strategic and International Studies issued a report, Nuclear
Weapons in 21st Century U.S. National Security
, that listed one component of “a possible new
centrist package of nuclear initiatives” as a view commonly held by the committee, “Ratify the
Comprehensive Nuclear-Test-Ban Treaty (CTBT), if coupled with other interconnected nuclear
initiatives described below.” These initiatives include, among many others, “development of an
international nuclear forensics data bank,” “pursuit of a Fissile Material Cut-Off Treaty,” and
“[t]he U.S. should continue to refurbish and update its stockpile as necessary without creating
new nuclear weapon capabilities through the ‘spectrum of options’ approach.”196 The
Congressional Commission on the Strategic Posture of the United States released its report in
May 2009 and was divided on the issue of U.S. ratification of the CTBT, the only issue on which
it failed to reach agreement.197 A Council on Foreign Relations task force, in a 2009 report,

191 “2007 NPT PrepCom Chair’s factual summary (now to be called a Chair’s Paper),” May 11, 2007, available at
http://www.acronym.org.uk/npt/chair.pdf.
192 “First session of the Preparatory Committee for the 2010 Review Conference of the Parties to the Treaty on the
Non-Proliferation of Nuclear Weapons, General Debate, Statement by Ambassador Rudiger Ludeking, Deputy
Commissioner of the Federal Government [of Germany] for Arms Control and Disarmament on behalf of the European
Union,” Vienna, April 30, 2007 p. 5, available at http://www.reachingcriticalwill.org/legal/npt/prepcom07/statements/
30aprilEU.pdf.
193 Reaching Critical Will, “Government Statements from the second session of the Preparatory Committee for the
2010 nuclear Non-Proliferation Treaty Review Conference
28 April 9–May 2008,” at http://www.reachingcriticalwill.org/legal/npt/prepcom08/statements.html.
194 “Registration as UN Document of a Joint Statement of 4th Comprehensive Nuclear-Test-Ban Treaty (CTBT)
Ministerial Meeting,” States News Service, January 8, 2009.
195 U.N. General Assembly. 63rd General Assembly. 61st Meeting (AM). “On Recommendation of First Committee,
General Assembly Adopts 57 Texts ...,” GA/10792, December 2, 2008.
196 “Nuclear Weapons in 21st Century U.S. National Security,” report by a joint working group of the American
Association for the Advancement of Science, the American Physical Society, and the Center for Strategic and
International Studies, December 2008, pp. ii, 7, 9.
197 Congressional Commission on the Strategic Posture of the United States. America’s Strategic Posture, final report.
Washington, DC, United States Institute of Peace Press, May 2009, pp. 81-87, http://www.usip.org/files/
(continued...)
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“believes that the benefits outweigh the costs and that the CTBT is in U.S. national security
interests.”198 On September 23, 2010, 24 foreign ministers issued a joint statement on the CTBT
calling on “all States that have not yet done so to sign and ratify the Treaty without delay” and
committing themselves “to make the Treaty a focus of attention at the highest political level.”199
On December 2, 2011, the U.N. General Assembly adopted a resolution (A/RES/66/64) urging
early entry into force of the CTBT; the vote was 175 in favor, 1 against (North Korea), and 3
abstentions (India, Mauritius, Syria). In contrast to the similar resolution in 2008, this resolution
had the sponsorship of all five nuclear weapon states as recognized by the NPT.200
In September 2012, the Sixth Ministerial Meeting on the Comprehensive Nuclear-Test-Ban
Treaty issued a statement reaffirming their “strongest support for the early entry into force” of the
CTBT, called on states that have not done so to sign and ratify the treaty, noted that with the
exception of North Korea, “the voluntary nuclear test moratorium has become a de facto
international norm in the 21st Century,” and pointed to advances made by the CTBTO Preparatory
Commission in building the verification regime for the treaty.201 On December 3, the U.N.
General Assembly adopted a resolution urging states that have not done so to sign and ratify the
CTBT. The vote was 184 for, 1 against (North Korea), and 3 abstentions (India, Mauritius,
Syria).202
On December 5, 2013, the U.N. General Assembly adopted a resolution (A/RES/68/68) stressing
the importance of early entry into force of the CTBT; the vote was 181 in favor, 1 against (North
Korea), and 3 abstentions (India, Mauritius, Syria).203 The Seventh Ministerial Meeting on the
Comprehensive Nuclear-Test-Ban Treaty was held on September 26, 2014.204 As noted earlier, at
the meeting Secretary of State Kerry reiterated the Administration’s “unshakable commitment to
seeing this treaty ratified and entered into force.” On December 2, 2014, the U.N. General
Assembly adopted Resolution A/Res/69/81, which urged states that have not done so to sign and

(...continued)
America's_Strategic_Posture_Auth_Ed.pdf.
198 Council on Foreign Relations. Independent Task Force Report No. 62. U.S. Nuclear Weapons Policy, 2009, p. 89.
199 “Joint Ministerial Statement on the CTBT,” New York, September 23, 2010, http://www.ctbto.org/fileadmin/
user_upload/public_information/2010/STATEMENTRev.16.09.pdf.
200 United Nations. 66th General Assembly. “General Assembly Gravely Concerned about Status of UN Disarmament
Machinery, Especially in Conference on Disarmament …,” press release, December 2, 2011, document GA/11182,
http://www.un.org/News/Press/docs//2011/ga11182.doc.htm.
201 For the final statement of the meeting, see “Joint Ministerial Statement on the CTBT,” September 27, 2012,
http://www.ctbto.org/fileadmin/user_upload/statements/CTBT_Joint_Ministerial_Statement_27_September_2012.pdf.
Statements by participants in the meeting are available at http://www.ctbto.org/press-centre/highlights/2014/executive-
secretary-meets-secretary-of-state-john-kerry-and-other-world-leaders/ (bottom of page).
202 United Nations. General Assembly. “General Assembly, in Wake of High-Stakes Debate in First Committee that
Championed Common Positions but Fell Short of Bridging Divides, Adopts 58 Texts,” December 3, 2012,
http://www.un.org/News/Press/docs//2012/ga11321.doc.htm. The text of the resolution, number 67/76,
“Comprehensive Nuclear-Test-Ban Treaty,” is here: http://www.un.org/ga/search/view_doc.asp?symbol=A/RES/67/76.
203 United Nations, 68th General Assembly, “Capping Intensive Disarmament Committee Session, General Assembly
Adopts 53 Texts on Wide Range of Pressing International Security Concerns,” press release, December 5, 2013,
document GA/11463, http://www.un.org/News/Press/docs//2013/ga11463.doc.htm. For text of the resolution, see
United Nations, 68th General Assembly, Resolution adopted by the General Assembly on 5 December 2013 …
[A/Res]68/68. “Comprehensive Nuclear-Test-Ban Treaty,” December 11, 2013, http://www.un.org/en/ga/search/
view_doc.asp?symbol=A/RES/68/68.
204 “Joint Ministerial Statement on the CTBT,” September 26, 2014, New York, http://www.ctbto.org/fileadmin/
user_upload/statements/2014_minsterial_meeting/2014_joint_ministerial_statement_final.pdf.
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ratify the CTBT as soon as possible.205 The vote was 179 for, 1 against (North Korea), and 3
abstentions (India, Mauritius, Syria). See “CTBT Negotiations and the Nuclear Nonproliferation
Treaty” for additional discussion of the relationship between the CTBT and NPT.
Budget of the CTBTO Preparatory Commission
The PrepCom uses the calendar year as its fiscal year. Its assessed budget is presented in dollars
plus euros. Its 2015 budget is $38.0 million plus €70.3 million or, using an exchange rate of €1 =
$1.09 as of May 26, 2015, $114.6 million. As of that date, about 54.6% of this assessment had
been collected.206 The U.S. assessment is 22.39% of the total or, in dollars, $25.6 million. Since
the United States pays the PrepCom once the U.S. budget is signed into law, almost all ($24.3
million) of the 2015 assessment remained outstanding as of May 26, 2015. The United States had
no outstanding prior year balance due as of that date.
U.S. funding for the PrepCom is FY2002 actual, $16.6 million; FY2003 actual, $18.2 million;
FY2004 actual, $18.9 million; FY2005 actual, $18.8 million; FY2006 actual, $14.2 million;
FY2007 actual, $13.5 million; and FY2008 appropriated, $23.8 million (net of an across-the-
board cut in the Consolidated Appropriations Act). The FY2009 request was $9.9 million; P.L.
111-8, FY2009 Omnibus Appropriations Act, provided $25.0 million. The FY2010 appropriation
was $30.0 million. FY2011 actual funding was $33.0 million plus a special contribution of $7.5
million. FY2012 actual funding was $33.0 million plus a special contribution of $8.9 million.
FY2013 actual funding, reflecting the full-year continuing resolution, was $31.3 million plus a
special contribution of $7.1 million. The FY2014 actual funding was $31.0 million plus a special
contribution of $1.0 million. The FY2015 request was $30.3 million plus a special contribution of
$100,000. The FY2016 request was a total of $33.0 million, with no breakout between regular
assessment and special contribution. These funds are in the Foreign Operations budget under
Nonproliferation, Antiterrorism, Demining, and Related Programs.207
The Bush Administration’s FY2007 budget justification stated that these funds “pay the U.S.
share for the ongoing development and implementation of the International Monitoring System
(IMS), which supplements U.S. capabilities to detect nuclear explosions. Since the United States
does not seek ratification and entry-into-force of the CTBT, none of the funds will support
Preparatory Commission activities that are not related to the IMS.”208 The Obama Administration
has taken a different approach. In September 2009, Secretary of State Clinton said, “we are
prepared to pay our share of the Preparatory Commission budget so that the global verification

205 United Nations. General Assembly. “Resolution Adopted by the General Assembly on 2 December 2014: …,
69/81. Comprehensive Nuclear-Test-Ban Treaty,” distributed December 11, 2014, p. 2, http://www.un.org/en/ga/
search/view_doc.asp?symbol=A/RES/69/81.
206 Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, “CTBTO Member States’ Payment as at 26-
May-2015,” p. 4, http://www.ctbto.org/fileadmin/user_upload/treasury/
22._26_May2015_Member_States__Payments.pdf.
207 For the FY2016 request, see U.S. Department of State. Congressional Budget Justification, Foreign Operations,
Appendix 2, Fiscal Year 2016, c. February 2015, pp. 71-73, http://www.state.gov/documents/organization/238221.pdf.
208 U.S. Department of State. Summary and Highlights, International Affairs Function 150, Fiscal Year 2007 Budget
Request,
p. 40, at http://www.state.gov/documents/organization/60297.pdf.
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regime will be fully operational when the CTBT enters into force.”209 In 2010, the United States
paid off an outstanding prior years balance of $22.323 million.210
The Administration’s FY2011 request for the PrepCom was in two parts. A “voluntary
contribution” of $33 million “helps to fund the establishment, operation, and maintenance of the
worldwide International Monitoring System.” In addition, “new for FY 2011, a voluntary
contribution to the Preparatory Commission of the Comprehensive Nuclear-Test-Ban Treaty
Organization ($10 million) will fund specific projects to increase the effectiveness and efficiency
of the Treaty’s verification regime.”211
The Administration’s FY2012 request for the PrepCom was in the same two parts, $33.0 million
for the IMS and $7.5 million for specific projects.212 In September 2011, Under Secretary
Tauscher said that in August, the United States announced a contribution of $8.9 million to the
CTBTO PrepCom “to support projects that will accelerate development of the CTBT verification
regime,” and in September, she said, the United States “concluded a Memorandum of
Understanding with the Provisional Technical Secretariat to contribute up to $25.5 million to
underwrite the rebuilding of the hydroacoustic monitoring station on Crozet Island in the southern
Indian Ocean.”213
The FY2013 request stated, “The voluntary contribution to the Preparatory Commission of the
Comprehensive Nuclear-Test-Ban Treaty Organization ($33 million) helps to fund the
establishment, operation, and maintenance of the worldwide International Monitoring System. In
addition, $3.5 million will fund specific projects to increase the effectiveness and efficiency of
the Treaty’s verification regime.”214 For FY2014, the request was $31.0 million for the IMS and
$1.0 million as special contributions. Among other things, the latter was intended to assist the
CTBTO’s Provisional Technical Secretariat in “efforts to engage medical isotope producers to use
techniques to reduce their xenon emissions, provide information on such emissions to the IDC,
and begin defining how medical isotope data should be used when it is received by the IDC.”215
These isotopes are of concern to the IMS, as discussed under “Key Provisions of the CTBT.” As
noted, the Administration’s FY2015 request was $30.3 million plus a special contribution of
$100,000, and the FY2016 request was a total of $33.0 million.

209 Clinton, “Remarks at CTBT Article XIV Conference,” p. 4.
210 Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, “CTBTO Member States’ Payment as at 05-
Nov-2010,” p. 4.
211 U.S. Department of State. Executive Budget Summary: Function 150 & Other International Programs Fiscal Year
2011,
2010, pp. 81-82, http://www.state.gov/documents/organization/135888.pdf.
212 U.S. Department of State. Executive Budget Summary: Function 150 & Other International Programs, Fiscal Year
2012,
pp. 104-105, http://www.state.gov/documents/organization/156214.pdf.
213 U.S. Department of State. Ellen Tauscher, Under Secretary for Arms Control and International Security, remarks at
CTBT Article XIV Conference, New York, NY, September 23, 2011.
214 U.S. Department of State. Congressional Budget Justification, Volume 2, Foreign Operations, Fiscal Year 2013, p.
126, http://www.state.gov/documents/organization/185014.pdf.
215 U.S. Department of State, Foreign Operations: Congressional Budget Justification, Fiscal Year 2014, Volume 2,
April 2013, p. 208, http://www.state.gov/documents/organization/208290.pdf.
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Stockpile Stewardship
P5 states want to maintain their nuclear warheads under a CTBT. For example, in his Prague
speech of April 2009, President Obama expressed “America’s commitment to seek the peace and
security of a world without nuclear weapons” and pledged to pursue U.S. ratification of the
CTBT, but he also stated, “As long as these weapons exist, the United States will maintain a safe,
secure and effective arsenal to deter any adversary, and guarantee that defense to our allies.”216 To
this end, the P5 states have “stockpile stewardship” programs to maintain their nuclear weapons,
and have maintained and upgraded their scientific and technical capabilities to do so. Nonnuclear
nations fear that the P5 will continue to design new warheads under a CTBT, using computation
and nonnuclear experiments instead of testing.
Congress established the National Nuclear Security Administration (NNSA) in Title XXXII of
P.L. 106-65, FY2000 National Defense Authorization Act, as a semiautonomous DOE agency to
manage stewardship and related programs. In NNSA’s budget, stewardship is funded by the
Weapons Activities account, which has four main elements:
• Directed Stockpile Work, activities directly supporting weapons in the stockpile;
• Research, Development, Test and Evaluation Programs (formerly Campaigns),
which NNSA calls “efforts to develop and maintain critical capabilities, tools,
and processes needed to support science based stockpile stewardship,
refurbishment, and continued certification of the stockpile over the long-term in
the absence of underground nuclear testing”217;
• Readiness in Technical Base and Facilities, which funds material recycle and
recovery, recapitalization of facilities, and construction of facilities; and
• Infrastructure and Safety, which is charged with maintaining, operating, and
modernizing NNSA’s infrastructure.
Weapons Activities contains other components as well. For a discussion of stockpile stewardship
programs and budgets, see CRS Report R43948, Energy and Water Development: FY2016
Appropriations for Nuclear Weapons Stockpile Stewardship
, by Jonathan E. Medalia.
Weapons Activities appropriations were: FY2001, $5.006 billion; FY2002, $5.429 billion;
FY2003, $5.954 billion; FY2004, $6.447 billion; FY2005, $6.626 billion; FY2006, $6.370
billion; FY2007, $6.259 billion; FY2008, $6.302 billion; FY2009, $6.380 billion; FY2010,
$6.384 billion; FY2011, $6.896 billion; FY2012, $7.214 billion; and FY2013, $6.971 billion. The
latter amount reflected the sequester and the across-the-board rescission.218 The FY2014 enacted
amount was $7.781 billion. The FY2015 enacted amount was $8.180 billion, and the FY2016
request was $8.847 billion.219

216 U.S. White House. . “Remarks by President Obama,” Hradcany Square, Prague, Czech Republic, April 5, 2009.
217 U.S. Department of Energy. Office of Chief Financial Officer. FY 2016 Congressional Budget Request, Volume 1,
National Nuclear Security Administration, DOE/CF-0107, February 2015, p. 62, http://www.energy.gov/sites/prod/
files/2015/02/f19/FY2016BudgetVolume1%20_1.pdf.
218 The National Nuclear Security Administration provided CRS with information on the FY2013 appropriation, e-mail,
June 4, 2013.
219 U.S. Department of Energy. FY 2016 Congressional Budget Request, Volume 1, p. 1.
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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

Stockpile Stewardship and the CTBT
Stewardship bears on Senate advice and consent to CTBT ratification. (It also was an issue in
Senate debate on advice and consent to ratification of New START, the New Strategic Arms
Reduction Treaty.) Beginning with the Nuclear Test Ban Treaty of 1963, the United States has
implemented “safeguards,” or unilateral steps to maintain nuclear security consistent with treaty
limitations. President Kennedy’s agreement to safeguards was critical for obtaining Senate
approval of the 1963 treaty. Safeguards were modified in 1990 as part of the resolutions of
ratification for the Threshold Test Ban Treaty and Peaceful Nuclear Explosions Treaty. The
safeguards were modified again by President Clinton. In his August 11, 1995, speech announcing
a zero-yield CTBT as a goal, he stated:
As a central part of this decision, I am establishing concrete, specific safeguards that define
the conditions under which the United States will enter into a comprehensive test ban. These
safeguards will strengthen our commitments in the areas of intelligence, monitoring and
verification, stockpile stewardship, maintenance of our nuclear laboratories, and test
readiness.220
These safeguards are: Safeguard A: “conduct of a Science Based Stockpile Stewardship program
to insure a high level of confidence in the safety and reliability of nuclear weapons in the active
stockpile”; Safeguard B: “maintenance of modern nuclear laboratory facilities and programs”;
Safeguard C: “maintenance of the basic capability to resume nuclear test activities prohibited by
the CTBT”; Safeguard D: “a comprehensive research and development program to improve our
treaty monitoring”; Safeguard E: intelligence programs for “information on worldwide nuclear
arsenals, nuclear weapons development programs, and related nuclear programs”; and Safeguard
F: the understanding that if the Secretaries of Defense and Energy inform the President “that a
high level of confidence in the safety or reliability of a nuclear weapon type which the two
Secretaries consider to be critical to our nuclear deterrent could no longer be certified, the
President, in consultation with Congress, would be prepared to withdraw from the CTBT under
the standard ‘supreme national interests’ clause in order to conduct whatever testing might be
required.”221 The Clinton Administration transmitted the CTBT to the Senate with virtually
identical safeguards in 1997, and the Senate modified these safeguards further in adopting an
amendment to the resolution of ratification of the CTBT. (The amendment passed, but the
resolution was defeated.)
Regarding the stewardship program, President Clinton said that the Secretary of Energy and the
directors of the nuclear weapons laboratories had assured him that the United States could
maintain its nuclear deterrent under a CTBT through a science-based stockpile stewardship
program. “In order for this program to succeed,” he said, “both the administration and the
Congress must provide sustained bipartisan support for the stockpile stewardship program over
the next decade and beyond.”222

220 President William J. Clinton, “Remarks Announcing a Comprehensive Nuclear Weapons Test Ban,” August 11,
1995, in U.S. National Archives and Records Administration. Office of the Federal Register. Weekly Compilation of
Presidential Documents,
August 14, 1995, p. 1432.
221 U.S. White House. Office of the Press Secretary. “Fact Sheet: Comprehensive Test Ban Treaty Safeguards,” August
11, 1995, 1 p.
222 President William J. Clinton, “Statement on a Comprehensive Nuclear Weapons Test Ban,” August 11, 1995, in
U.S. National Archives and Records Administration. Office of the Federal Register. Weekly Compilation of
Presidential Documents,
August 14, 1995, p. 1433.
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Safeguard F was codified by Section 3141 of P.L. 107-314, the FY2003 National Defense
Authorization Act. As summarized by the State Department, this section provided that
The Directors of the three DOE nuclear weapons laboratories—Los Alamos National
Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and Sandia National
Laboratories (SNL)—are required to complete annual assessments of the safety, reliability,
and performance of each weapon type in the nuclear weapons stockpile. In addition, the
Commander of U.S. Strategic Command provides an assessment of the military effectiveness
of the stockpile. These assessments also include a determination as to whether it is necessary
to conduct an underground nuclear test to resolve any identified issues. The Secretaries of
Energy and Defense are required to submit these reports unaltered to the President, along
with any conclusions the Secretaries consider appropriate.223
As of May 2015, the laboratories had completed 19 annual assessments and the 20th was in
progress.224
For a discussion of the possible role of updated safeguards in a future CTBT debate, see CRS
Report R40612, Comprehensive Nuclear-Test-Ban Treaty: Updated “Safeguards” and Net
Assessments
, by Jonathan E. Medalia.
The ability of the stewardship program to maintain nuclear weapons without testing was a crucial
issue in the 1999 Senate debate on the CTBT. The treaty’s opponents claimed that stewardship
offered no guarantee of maintaining weapons, and that experiments, computer models, and other
techniques might offer no clue to some problems that develop over time. They further argued that
it could be perhaps a decade before the tools for the program were fully in place, and by that time
many weapon designers with test experience would have retired. Supporters held that the program
was highly likely to work, with the stockpile already certified three times, and that safeguard “F”
provided for U.S. withdrawal from the treaty in the event high confidence in a key weapon type
could not be maintained without testing.
Several reports from 2009 raised concerns about stockpile stewardship. The Congressional
Commission on the Strategic Posture of the United States observed, “The physical infrastructure
is in serious need of transformation.... The intellectual infrastructure is also in serious trouble.”225
A Council on Foreign Relations task force found, “concerns about ensuring the highest caliber
workforce at the weapons laboratories.”226 And a JASON report stated, “continued success of
stockpile stewardship is threatened by lack of program stability, placing any LEP [life extension
program] strategy at risk” and “the study team is concerned that this [nuclear weapons] expertise
is threatened by lack of program stability, perceived lack of mission importance, and degradation
of the work environment.”227 On the other hand, the latter report stated, “JASON finds no
evidence that accumulation of changes incurred from aging and LEPs have increased risk to
certification of today’s deployed nuclear warheads,” and “lifetimes of today’s nuclear warheads

223 U.S. Department of State. Bureau of Arms Control, Verification, and Compliance. Fact Sheet: “Annual Assessment
of the U.S. Nuclear Weapons Stockpile,” December 18, 2012, http://www.state.gov/t/avc/rls/202013.htm.
224 Information provided by Los Alamos National Laboratory, email, May 27, 2015.
225 Congressional Commission on the Strategic Posture of the United States, America’s Strategic Posture, p. 62.
226 Council on Foreign Relations. Independent Task Force Report No. 62, U.S. Nuclear Weapons Policy, p. 76.
227 “Lifetime Extension Program (LEP) Executive Summary,” JASON Program Office, the MITRE Corporation, JSR-
09334E, September 9, 2009, pp. 3-4, http://www.armscontrol.org/system/files/
JASON%20LEP%20REPORT%20SUMMARY%2009-09_0.pdf.
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could be extended for decades, with no anticipated loss in confidence, by using approaches
similar to those employed in LEPs to date.”228 In January 2010, an op-ed by George Shulz,
William Perry, Henry Kissinger, and Sam Nunn argued that “adequate and stable funding” for the
nuclear weapons program was “urgently needed.”229
Section 1251 of the FY2010 National Defense Authorization Act (H.R. 2647, P.L. 111-84)
required the President to submit a report on, among other things, a plan to enhance the safety,
security, and reliability of the U.S. nuclear stockpile; modernize the nuclear weapons complex;
and maintain nuclear weapon delivery platforms. On December 15, 2009, 40 Republican Senators
and Senator Joseph Lieberman, in a letter to President Obama, cited Section 1251 and said that “a
plan to modernize the U.S. nuclear deterrent” should include
Full and timely Lifetime Extension Programs for the B61 and W76 warheads consistent with
military needs.
Funding for a modern warhead that includes new approaches to life extension involving
replacement, or, possibly, component reuse.
Full funding for stockpile surveillance work through the nuclear weapons complex, as well
as the science and engineering campaigns at the national laboratories.
Full funding for the timely replacement of the Los Alamos plutonium research and
development and analytical chemistry facility, the uranium facilities at the Oak Ridge Y-12
plant, and a modern pit facility.230
The Administration took several actions in response to these concerns. Vice President Joe Biden
wrote in January 2010, “For almost a decade, our [nuclear weapon] laboratories and facilities
have been underfunded and undervalued.” The FY2011 budget request for NNSA Weapons
Activities, he continued, “reverses this decline and enables us to implement the president’s
nuclear-security agenda.”231 That budget, submitted in February, increased by $624.4 million, to
$7,008.8 million. The Nuclear Posture Review, submitted in April, included a chapter,
“Sustaining a Safe, Secure, and Effective Nuclear Arsenal,” that called for extending the service
life of nuclear warheads, increasing investment in the work force of the nuclear weapons
complex, funding the Chemistry and Metallurgy Research Replacement Project at Los Alamos
National Laboratory, and developing a new Uranium Processing Facility at the Y-12 National
Security Complex.232 In May, the President submitted New START to the Senate and provided a
classified report as required by Section 1251 of the FY2010 National Defense Authorization Act.
An unclassified one-page description of that report presented a cost projection for the nuclear
weapons stockpile and infrastructure for FY2011-FY2020, and stated that “the Administration
intends to invest $80 billion in the next decade to sustain and modernize the nuclear weapons
complex.”233 The directors of the three nuclear weapons laboratories commented on the Nuclear
Posture Review as follows:

228 Ibid., p. 2. Original text was bolded.
229 George Shultz, William Perry, Henry Kissinger, and Sam Nunn, “How to Protect Our Nuclear Deterrent,” Wall
Street Journal
, January 20, 2010, p. 17.
230 The Honorable Mitch McConnell et al., letter to The Honorable Barack Obama, President, December 15, 2009.
231 Vice President Joe Biden, “The President’s Nuclear Vision,” Wall Street Journal, January 29, 2010, p. 15.
232 U.S. Department of Defense, Nuclear Posture Review, pp. 37-43.
233 U.S. White House. “The New START Treaty—Maintaining a Strong Nuclear Deterrent,” May 13, 2010,
(continued...)
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We believe that the approach outlined in the NPR, which excludes further nuclear testing and
includes the consideration of the full range of life extension options (refurbishment of
existing warheads, reuse of nuclear components from different warheads and replacement of
nuclear components based on previously tested designs), provides the necessary technical
flexibility to manage the nuclear stockpile into the future with an acceptable level of risk. We
are reassured that a key component of the NPR is the recognition of the importance of
supporting “a modern physical infrastructure–comprised of the national security laboratories
and a complex of supporting facilities–and a highly capable workforce with the specialized
skills needed to sustain the nuclear deterrent.”234
Nonetheless, questions remained about the adequacy of stockpile stewardship, even as
augmented, to sustain the nuclear arsenal. In letters to Representative Michael Turner, ranking
Member, Subcommittee on Strategic Forces, Committee on Armed Services, Michael Anastasio,
Director, Los Alamos National Laboratory, stated that “the available mitigation actions [for
extending warhead lives], such as changes external to the nuclear package, or relaxation of certain
military requirements, are reaching their limits.” George Miller, Director, Lawrence Livermore
National Laboratory, wrote, “The [warhead] surveillance program is becoming inadequate.”235 In
a statement in April on the New START Treaty, Senators John McCain and Jon Kyl said, “We
continue to believe it will be difficult for it to pass the Senate without the fully funded robust
nuclear weapons modernization program required by section 1251 of the National Defense
Authorization Act of 2010.”236 In a hearing on the nuclear weapons complex and New START in
July, Senator Bob Corker said, “The issue that we’re focused on today is the most crucial issue
that we need to be focusing on … if you look at this 10-year plan [for Weapons Activities], that,
in essence, we’re still, even with the first year input that we have, which I think we all welcome,
that there’s still about a $10 billion shortfall to do the things that need to be done over this next 10
years to really modernize and do the things that we need to do.”237
While the FY2011 Weapons Activities funding request provided a substantial increase over the
FY2010 level, a key sticking point in the debate over New START was the level of funding the
Administration would provide over the long term for the nuclear weapons program in general and
the nuclear weapons complex in particular. According to a press article, “Republicans have
sought some guarantee that promises in the Obama administration’s 10-year plan to modernize
the nuclear weapons complex will be carried out.”238 The Administration and Congress sought to
meet these concerns. The FY2011 continuing resolution, P.L. 111-242 (H.R. 3081), maintained
most spending at the FY2010 level, with few exceptions. One exception (Section 122) was to
fund the Weapons Activities account at the rate requested for FY2011, $7,008.8 million, rather

(...continued)
http://www.america.gov/st/texttrans-english/2010/May/20100514114003xjsnommis0.6300318.html.
234 Sandia National Laboratories, “Tri-Lab Directors’ Statement on the Nuclear Posture Review,” press release, April 9,
2010, https://share.sandia.gov/news/resources/news_releases/tri-lab-directors%E2%80%99-statement-on-the-nuclear-
posture-review/.
235 U.S. Congress. House. Committee on Armed Services. “Turner Releases Lab Director Letters on JASON Life
Extension Report in Advance of Nuclear Budget Hearing,” press release, March 25, 2010,
http://republicans.armedservices.house.gov/news/PRArticle.aspx?NewsID=962. This document contains links to the
letters from the three laboratory directors.
236 “Statement by Senators Jon Kyl and John McCain on START Treaty,” press release, April 8, 2010,
http://kyl.senate.gov/record_print.cfm?id=323710.
237 Statement by Senator Bob Corker, in U.S. Congress. Senate. Committee on Foreign Relations. Hearing on New
START Treaty, July 15, 2010, transcript by CQ Transcriptions.
238 Walter Pincus, “Similar Treaty but a Different Republican Reaction,” Washington Post, August 10, 2010, p. 15.
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than at the FY2010 rate of $6,384.4 million. In November 2010, the Administration offered
additional Weapons Activities funds. According to a press report, “Republicans have conditioned
their support for the [New START] treaty on a big budget increase to fix up the country’s aging
weapons-production facilities.” As a result, “in a last-minute bid to save [the treaty], the Obama
administration has offered to spend $4 billion more over five years on the U.S. nuclear weapons
complex.”239 The Administration presented this funding plan in a November 2010 update of the
1251 report. For FY2012, it called for an increase of $600 million, and for FY2012-FY2016 an
increase of $4.1 billion, compared to the previously planned level.240
In response, Senators Kyl and Corker sent a memo on November 24 to Republican Members
analyzing the revised funding plan. The memo stated, “In FY2010, the Obama administration
invested only $6.4 billion in the National Nuclear Security Administration Weapons Activities
funding line, a 20% loss in purchasing power from FY2005 alone.” It further stated that only
about $10 billion of the $80 billion in the original 1251 report was for new weapons activity. It
found that the updated plan “satisfied many, but not all, of the initial questions we had earlier
expressed.” The memo noted several “remaining concerns,” including a need for more funds for a
uranium facility at Y-12 and a plutonium facility at Los Alamos, a commitment to advance
funding for these facilities, and more funds (pending a review) for stockpile surveillance. Further,
“The Administration should not engage in further cuts to our deployed or non-deployed stockpile
without first determining if such cuts our in our national security interest and then obtaining
corresponding reductions in other nations’ nuclear weapons stockpiles, such as Russia’s large
stockpile of weapons not limited by New START (e.g., its tactical nuclear weapons).”241
In a letter of November 30 to the directors of Lawrence Livermore, Los Alamos, and Sandia
National Laboratories, Senators Kerry and Lugar noted that the directors had testified in July that
the original Section 1251 report was a good start but also expressed concerns. The Senators asked
the directors for their opinion of the revised 1251 report.242 In a letter of December 1, the
directors responded that “we are very pleased by the update to the Section 1251 Report, as it
would enable the laboratories to execute our requirements for ensuring a safe, secure, reliable and
effective stockpile under the Stockpile Stewardship and Management Plan … it clearly responds
to many of the concerns that we and others have voiced in the past about potential future-year
funding shortfalls, and it substantially reduces risks to the overall program.”243

239 Mary Beth Sheridan and Walter Pincus, “Sources: $4 Billion Bid to Save START,” Washington Post, November 13,
2010, p. 3.
240 U.S. “November 2010 Update to the National Defense Authorization Act of FY2010 Section 1251 Report: New
START Treaty Framework and Nuclear Force Structure Plans,” November 2010, p. 2, http://www.scribd.com/doc/
43366094/Section-1251-Update-nov-2010. Hereinafter “November 2010 Update to the 1251 Report.”
241 “Memo from Sen. Jon Kyl, Sen. Bob Corker to Republican Members, November 24, 2010, re: Progress in Defining
Nuclear Modernization Requirements,” http://www.scribd.com/doc/44104068/Kyl-Corker-memo-to-Senate-colleagues-
on-nuclear-modernization-11-24-2010.
242 Letter to Michael Anastasio, Director, Los Alamos National Laboratory, from Senators Richard Lugar, Ranking
Member, and John Kerry, Chairman, Senate Committee on Foreign Relations, November 30, 2010,
http://lugar.senate.gov/issues/start/pdf/12012010Letters.pdf. (The Senators sent similar letters to the directors of Los
Alamos and Sandia National Laboratories.)
243 Letter to The Honorable John Kerry and The Honorable Richard Lugar, Senate Committee on Foreign Relations,
from George Miller, Lawrence Livermore National Laboratory, Michael Anastasio, Los Alamos National Laboratory,
and Paul Hommert, Sandia National Laboratories, December 1, 2010, 2 p., http://lugar.senate.gov/issues/start/pdf/
12012010Letters2.pdf
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As noted above, for FY2012, the House voted to authorize the amount requested for Weapons
Activities, and the Senate Armed Services Committee recommended a reduction of $1 million. In
contrast, the House voted to reduce Weapons Activities appropriations by $497.7 million from the
request, and the Senate Appropriations Committee recommended a reduction of $439.7 million.
For FY2013, the Administration requested $7,577.3 million. This compares to a request of $7.9
billion projected in the November 2010 1251 report. Further, that report stated, “The
Administration is committed to fully fund the construction of the Uranium Processing Facility
(UPF) and the Chemistry and Metallurgy Research Replacement (CMRR).”244 The CMRR
Nuclear Facility (CMRR-NF), which was to have been completed in FY2023 on one spending
path,245 would have done analytical work on plutonium in support of pit production, permitting
the existing pit production facility (PF-4, or Plutonium Facility 4, at Los Alamos) to manufacture
50 to 80 pits per year. However, the FY2013 request contained no funds for CMRR-NF, instead
proposing “deferring CMRR Nuclear Facility construction for at least five years.”246 NNSA
planned an alternative plutonium strategy, doing work that would have been done at CMRR-NF
at other facilities, which would have permitted PF-4 to manufacture perhaps 20 to 30 pits per
year. The request also proposed increasing spending on UPF above the figure projected in the
1251 report. The Administration had also stated in the 1251 report that the life extension program
for the W76 warhead “will be fully funded for the life of the program at $255 million
annually,”247 but requested $174.9 million.
The change to CMRR-NF was particularly controversial. Thomas D’Agostino, Under Secretary
for Nuclear Security and Administrator, National Nuclear Security Administration, presented the
case for deferring the facility to the Senate Appropriations Committee:
in close consultation with our national laboratories and national security sites, we are
adjusting our plutonium strategy by deferring for at least five years construction of the
Chemistry and Metallurgy Research Replacement Nuclear Facility (CMRR-NF) project at
Los Alamos National Laboratory and focusing instead on how we can meet our plutonium
needs on an interim basis by using the capabilities and expertise found at existing facilities.
Utilizing existing facilities will allow us to meet anticipated near term requirements for
plutonium operations while focusing on other key modernization projects. Deferring CMRR-
NF will have an estimated cost avoidance from 2013 to 2017 that totals approximately $1.8
billion, which will help offset the costs of other priorities such as Weapons Lifetime
Extension programs and other infrastructure needs.248
The appropriations committees provided no funds for the facility, as requested. The Armed
Services Committees took a different view. The FY2013 defense authorization bill (H.R. 4310) as
passed by the House expressed the sense of Congress that up to $160 million in prior year funds

244 “November 2010 Update to the 1251 Report,” p. 5.
245 Ibid., p. 6.
246 U.S. Department of Energy. FY 2013 Congressional Budget Request: Volume 1, National Nuclear Security
Administration
, pp. 185.
247 “November 2010 Update to the 1251 Report,” p. 4.
248 “Statement of Thomas P. D’Agostino, Undersecretary for Nuclear Security and Administrator, National Nuclear
Security Administration, U.S. Department of Energy, on the Fiscal Year 2013 President’s Budget Request Before the
Senate Appropriations Committee Subcommittee on Energy and Water Development, March 21, 2012,” pp. 5-6,
available via http://www.appropriations.senate.gov/ht-energy.cfm?method=hearings.view&id=efa574fe-712c-40f4-
a8b2-c5a782bbd5f0.
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should be used to continue design and construction of CMRR-NF in FY2013. The Senate Armed
Services Committee report on FY2013 defense authorizations stated,
The committee is strongly concerned with the budget proposal to defer “by at least 5 years”
the replacement project for the Chemistry and Metallurgy Research Replacement Nuclear
Facility (CMRR-NF) building at Los Alamos National Laboratory, New Mexico.
A deferral “for at least 5 years” appears to be a cancellation. Based on the analysis the
committee has received to date, it appears that such a cancellation would have an adverse
impact on nuclear modernization programs.249
The committee recommended authorizing $150.0 million for CMRR-NF construction out of
funds appropriated for Weapons Activities for FY2013. In response, a Statement of
Administration Policy on the Senate bill stated,
The Administration strongly objects to section 3111, which would require construction of the
Chemistry and Metallurgy Research Replacement (CMRR) facility to begin in 2013. The
Departments of Defense and Energy agree that, in light of today’s fiscal environment,
CMRR can be deferred for at least five years, and funds reallocated to support higher priority
nuclear weapons goals. An interim strategy will be implemented to provide adequate support
to plutonium pit manufacturing and storage needs until a long-term solution can be
implemented.250
Section 3114 of the conference report (H.Rept. 112-705), as passed by both houses, required
among other things that
• CMRR-NF be built;
• its cost may not exceed $3.7 billion (unless the Secretary of Energy submits a
detailed justification to Congress for any increase);
• the building must commence operations by December 31, 2026;
• $70.0 million in FY2013 NNSA funds be available for construction of CMRR-
NF;
• prior year funds authorized for the CMRR project be available for construction of
CMRR-NF; and
• any alternative plutonium strategy must include full operational capability of
CMRR-NF by December 31, 2026.
However, the conference report authorized no construction funds for this project for FY2013, and
as of late December 2012, a Los Alamos Site Office spokeswoman reportedly said that “all
planned closure elements” for CMRR-NF were “essentially completed.”251 For FY2015, instead

249 U.S. Congress, Senate Committee on Armed Services, National Defense Authorization Act for Fiscal Year 2013,
Report to accompany S. 3254, 112th Cong., 2nd sess., June 4, 2012, S.Rept. 112-173 (Washington: GPO, 2012), pp.
287-288.
250 U.S. White House. Executive Office of the President. Office of Management and Budget. “Statement of
Administration Policy: S. 2354—National Defense Authorization Act for FY 2013,” November 29, 2012,
http://www.whitehouse.gov/sites/default/files/omb/legislative/sap/112/saps3254s_20121129.pdf.
251 Todd Jacobson, “In Final Defense Authorization Act, Congress Looks to Revive CMRR-NF,” Nuclear Weapons &
Materials Monitor,
December 21, 2012, p. 4.
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of focusing on facilities, Section 3112 of P.L. 113-291, the Carl Levin and Howard P. “Buck”
McKeon National Defense Authorization Act for Fiscal Year 2015, focused on required capacity.
It mandated ramping up to produce at a rate of 80 pits per year for 90 days in 2027.
The Administration’s departure from the budget plan presented in the November 2010 1251
report may have ramifications for any future Senate consideration of the CTBT. A letter to
Secretary of Defense Leon Panetta from Senator Jon Kyl and seven other Senators urged
continuation of CMRR-NF with operation by 2024. It stated, “We believe that the linkage
between nuclear modernization and the New START Treaty was clearly defined at the time of
ratification and remains so today. Thus, we are concerned about the impact that failing to fulfill
this critical commitment could have on future treaties the Senate may be asked to consider.”252
The FY2016 budget request included out-year figures for Weapons Activities. For FY2016-
FY2020, Table 1 compares figures from the FY2016 request with those from the November 2010
update to the 1251 report. Requests from some earlier years were below the amounts in the latter
report by several hundred million dollars; for example, the FY2014 request was $7.868 billion,
while the November 2010 update to the 1251 report had projected a request for FY2014 of $8.4
billion. In contrast, the FY2016 request was very close to the amount shown in that report (lower
by $53 million) and the out-year projections were above the amounts in that report.
Table 1. Projected Budgets for Weapons Activities, FY2016-FY2020 ($ billions)
Using figures from the FY2016 NNSA budget request and the November 2010 update to the 1251report

FY2016 FY2017 FY2018 FY2019 FY2020
FY2016 NNSA
request
8.847 9.282 9.485 9.718 9.830
November 2010
1251 report
8.9 8.9-9.0 9.2-9.3 9.4-9.6 9.4-9.8
Sources: U.S. Department of Energy. Office of Chief Financial Officer. FY 2016 Congressional Budget Request,
Volume 1, National Nuclear Security Administration, DOE/CF-0107, February 2014, pp. 6-7; and U.S. White
House. November 2010 Update to the National Defense Authorization Act of FY2010 Section 1251 Report:
New START Treaty Framework and Nuclear Force Structure Plans, p. 9, http://www.lasg.org/CMRR/
Sect1251_update_17Nov2010.pdf.
For FY2015, the Administration proposed a plutonium strategy that included updating pit
production equipment in PF-4; moving some operations out of PF-4 to make more space for pit
production; cleaning out the vault in PF-4 that stores nuclear materials and moving excess
plutonium to the Waste Isolation Pilot Plant; using the Radiation Laboratory/Utility/Office
Building (RLUOB), a building completed in FY2010 near PF-4, for work supporting pit
production; building “modules” (buried concrete structures to be located near PF-4) to provide
added space for plutonium work; and reusing retired pits in warhead life extension programs.
NNSA anticipated that these and related activities would provide the capacity to manufacture 30
pits per year by 2026; other steps are being considered to boost pit production up to 80 pits per

252 Letter from Senators Jon Kyl, Ben Nelson, John McCain, Joe Lieberman, Bob Corker, Johnny Isakson, James M.
Inhofe, and Kelly Ayotte to The Honorable Leon E. Panetta, Secretary of Defense, June 29, 2012,
http://freebeacon.com/wp-content/uploads/2012/07/Kyl-et-al-nuclear.pdf.
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year by 2030.253 NNSA provides details on its plans in its Stockpile Stewardship and Management
Plan
.254 Three CRS reports deal with pit production.255
Stockpile Stewardship Experiments and Facilities
Nuclear tests used to provide end-to-end data on nuclear explosions. In the absence of such
testing, NNSA’s stockpile stewardship program uses many types of experiments, including those
described in this section, to simulate aspects of a nuclear explosion in order to gather data that can
be used in computer models and elsewhere to better understand how a nuclear explosion works.
Subcritical Experiments
As part of the stewardship program, NNSA is conducting subcritical experiments (SCEs). It
states, “Subcritical experiments examine the behavior of plutonium as it is strongly shocked by
forces produced by chemical high explosives.... The experiments are subcritical; that is, no
critical mass is formed and no self-sustaining nuclear chain reaction can occur; thus, there is no
nuclear explosion.”256 SCEs are conducted at Nevada National Security Site (NNSS, formerly
Nevada Test Site, NTS). All SCEs but one have been conducted in the U1a tunnel complex, about
1,000 feet underground at NNSS. That complex could contain explosions up to 500 pounds of
explosive and associated plutonium. Another SCE, “Unicorn,” was conducted in a “down-hole”
or vertical shaft configuration similar to an underground nuclear test, not in a tunnel, to exercise
operational readiness.257 SCEs try to determine if radioactive decay of aged plutonium would
degrade weapon performance. Several SCEs have been used to support certification of the W88
pit. (A pit is the “trigger” of a thermonuclear weapon.) In 1998, Secretary of Energy Bill
Richardson called SCEs “a key part of our scientific program to provide new tools and data that
assess age-related complications and maintain the reliability and safety of the nation’s nuclear
deterrent.”258 As they produce no chain reaction, the Clinton Administration saw them as
consistent with the CTBT. Critics counter that they would help design new weapons without
testing; are unnecessary; may look like nuclear tests if not monitored intrusively; and are
inconsistent with the spirit of a CTBT, which, critics believe, is aimed at halting nuclear weapons
development, not just testing. NNSA stated that subcritical experiments cost between $5 million
and $30 million.259 (For further information on subcritical experiments and test readiness, see

253 Presentation by Lt. Gen. Frank Klotz (USAF, Ret.), Administrator, National Nuclear Security Administration,
presentation at conference, “The Strategic Nuclear Enterprise: Implementing the Roadmap Ahead,” September 18,
2014, Washington, DC.
254 U.S. Department of Energy, Fiscal Year 2015 Stockpile Stewardship and Management Plan, Report to Congress,
Washington, DC, April 2014, http://nnsa.energy.gov/sites/default/files/nnsa/04-14-inlinefiles/2014-04-
11%20FY15SSMP_FINAL_4-10-2014.pdf.
255 See CRS Report R43406, U.S. Nuclear Weapon “Pit” Production Options for Congress; CRS Report R43685,
Manufacturing Nuclear Weapon “Pits”: A Decisionmaking Approach for Congress; and CRS Report R44033, Nuclear
Weapon “Pit” Production: Options to Help Meet a Congressional Requirement
, by Jonathan E. Medalia.
256 U.S. Department of Energy. National Nuclear Security Administration. Nevada Site Office. “NNSA Conducts
Pollux Subcritical Experiment at Nevada National Security Site, news release, December 6, 2012,
http://nnsa.energy.gov/mediaroom/pressreleases/pollux120612.
257 “Nanos Tours Nevada Test Site,” Daily Newsbulletin, Los Alamos National Laboratory, November 10, 2003, at
http://www.lanl.gov/orgs/pa/newsbulletin/2003/11/10/text04.shtml.
258 U.S. Department of Energy. “DOE to Conduct Fourth Subcritical Experiment; Scientific Data to Help Ensure the
Safety and Reliability Of the Stockpile Without Nuclear Testing,” press release, September 23, 1998.
259 U.S. Department of Energy. Office of Management, Budget and Evaluation/CFO. FY 2006 Congressional Budget
(continued...)
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CRS Report RL32130, Nuclear Weapon Initiatives: Low-Yield R&D, Advanced Concepts, Earth
Penetrators, Test Readiness
, by Jonathan E. Medalia.)
As of March 2015, there have been 28 SCEs: 1997: Rebound, July 2; Holog, September 18;
1998: Stagecoach, March 25; Bagpipe, September 26; Cimarron, December 11; 1999: Clarinet,
February 9; Oboe, September 30; Oboe 2, November 9; 2000: Oboe 3, February 3;
Thoroughbred, March 22; Oboe 4, April 6; Oboe 5, August 18; Oboe 6, December 14; 2001:
Oboe 8, September 26; Oboe 7 (held after Oboe 8), December 13; 2002: Vito (jointly with UK),
February 14; Oboe 9, June 7; Mario, August 29; Rocco, September 26; 2003: Piano, September
19; 2004: Armando, May 25; 2006: Krakatau (jointly with UK), February 23; Unicorn, August
30; 2010: Bacchus, September 15; Barolo A, December 1; 2011: Barolo B, February 2; 2012:
Pollux, December 5; 2014: Leda, August 12.260 An NNSA official stated that, for Pollux,
“Diagnostic equipment fielded by our scientists resulted in more data collected in this single
experiment than all other previous subcritical experiments.” Another official said, “Pollux will
provide a significant data set to verify [computer] codes important to laboratories’ stockpile
missions.”261 While the first 27 SCEs used plutonium, NNSA termed Leda an SCE even though it
used surrogate (i.e., non-plutonium) material.262
Other Experiments and Experimental Facilities
The laboratories have conducted two other types of experiments involving plutonium at NNSS.
“Thermos” experiments are material property studies. NNSA stated in March 2007 that they do
not use enough plutonium to sustain a chain reaction, and the plutonium “does not approximate
any part of weapons design.” The series involved 12 such experiments,263 which were conducted
between February and May 2007.264 The Joint Actinide Shock Physics Experimental Research
(JASPER) Facility is a gas gun that shoots a high-velocity projectile at a plutonium target to
produce “high shock pressures, temperatures, and strain rates similar to that of a nuclear weapon”
in the plutonium. According to NNSA, the resulting data help “refine the computer codes used to
certify the U.S. nuclear stockpile.265 As of August 2011, 88 JASPER experiments had been
conducted between March 2001 and April 2011, of which 34 used plutonium and 54 used
surrogate materials. From the third quarter of FY2011 through FY2012, NNSA conducted 13
JASPER experiments, of which 7 used plutonium.266 For FY2013, there were 13 experiments at

(...continued)
Request. Volume 1, National Nuclear Security Administration. DOE/ME-0046, February 2005, p. 88, at
http://www.mbe.doe.gov/budget/06budget/Content/Programs/Vol_1_NNSA_2.pdf.
260 Information provided by Nevada Field Office, NNSA, email, March 24, 2015.
261 U.S. Department of Energy. National Nuclear Security Administration. “NNSA Conducts Pollux Subcritical
Experiment at Nevada National Security Site,” press release, December 6, 2012, http://nnsa.energy.gov/mediaroom/
pressreleases/pollux120612.
262 Information provided by Nevada Field Office, NNSA, email, March 24, 2015.
263 “Small Thermos Experiments At Nevada Test Site Yield Excellent Data On Stockpile,” NNSA Newsletter, July
2007, p. 8, http://www.nnsa.energy.gov/sites/default/files/nnsa/newsletters/10/nl_2007Jul_NNSA_News.pdf.
264 Information provided by National Nuclear Security Administration, Nevada Site Office, personal communication,
August 3, 2011.
265 U.S. Department of Energy. National Nuclear Security Administration. Nevada Site Office. “Joint Actinide Shock
Physics Experimental Research (JASPER),” DOE/NV-1015, September 2004, at http://www.nv.doe.gov/library/
factsheets/DOENV_1015.pdf.
266 U.S. Department of Energy. National Nuclear Security Administration. “Summary of Experiments Conducted in
Support of Stockpile Stewardship,” October 2012 (covers FY2012 by quarter), http://nnsa.energy.gov/sites/default/
(continued...)
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JASPER, 7 of which used plutonium.267 In FY2014, 10 JASPER experiments were conducted, 5
of which used plutonium.268 And in the first quarter of FY2015, three such experiments were
conducted, all of which used plutonium.269
In addition to JASPER, NNSA facilities conduct other types of experiments in support of
stockpile stewardship, including the following, described in an NNSA report of mid-2015: the
Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility at Los Alamos, which provides
radiographic images of “moving, non-nuclear weapon assemblies”; the Contained Firing Facility,
operated by Livermore at a remote site, which also provides radiographic images of “moving,
non-nuclear weapon assemblies” but “has a substantially larger field of view than DARHT”; the
National Ignition Facility at Livermore, which is used to investigate” properties of material,
radiation, plasma,” and other aspects of nuclear explosions at temperatures and pressures “not
possible on any other experimental platform”; the Z-Machine at Sandia and the Omega laser
facility at the University of Rochester, for studying material properties; the High Explosive
Application Facility at Livermore, which studies properties of chemical explosives; high
explosive facilities at Los Alamos, which “investigate fundamental properties and reactions of
chemical explosives, detonators, and to conduct studies on materials”; the Los Alamos Neutron
Science Center (LANSCE), which generates neutrons to study material properties; proton
radiography at Los Alamos, which uses LANSCE “to produce protons for radiography of static
and dynamic materials”; the Big Explosives Experimental Facility at NNSS, which studies
“materials as they are merged together by high-explosives detonations”; and TA-55 at Los
Alamos, which has facilities to investigate properties of plutonium and other metals. 270 In
addition, the U1a facility at NNSS is used to conduct subcritical experiments and hydrodynamic
experiments. The latter “involve non-nuclear surrogate materials that mimic many of the
properties of nuclear materials. Hydrodynamics refers to the physics involved when solids, under
extreme conditions, begin to mix and flow like liquids.” 271 One experiment, “Leda,” conducted
August 12, 2014, “consisted of a plutonium surrogate material and high explosives to implode a
‘weapon-relevant geometry.’”272 According to NNSA, Leda “was a preparatory experiment for
the next series of subcritical experiments.”273

(...continued)
files/nnsa/12-12-inlinefiles/2012-12-06%20Quarterly%20SSP%20Experiment%20Summary-FY12-4Q.pdf, and
November 2011 (covers FY2011 by quarter), http://nnsa.energy.gov/sites/default/files/nnsa/inlinefiles/
Quarterly%20SSP%20Experiment%20Summary-FY11-4Q%20FINAL.pdf.
267 U.S. Department of Energy. National Nuclear Security Administration. “Summary of Experiments Conducted in
Support of Stockpile Stewardship,” October 2013, p. 3, http://nnsa.energy.gov/sites/default/files/nnsa/2013-10-
29%20Quarterly%20SSP%20Experiment%20Summary-FY13-4Q%20final.pdf.
268 U.S. Department of Energy. National Nuclear Security Administration. “Summary of Experiments Conducted in
Support of Stockpile Stewardship,” FY14, p. 3, http://nnsa.energy.gov/sites/default/files/nnsa/inlinefiles/Quarterly-
SSP-Experiment-Summary-Q4-FY14.pdf.
269 U.S. Department of Energy. National Nuclear Security Administration. “Summary of Experiments Conducted in
Support of Stockpile Stewardship,” Quarter 1, FY15, p. 3, http://nnsa.energy.gov/sites/default/files/
Quarterly%20SSP%20Experiment%20Summary-Q1FY15.pdf.
270 Ibid., pp. 2-3.
271 Los Alamos National Laboratory, “Los Alamos Conducts Important Hydrodynamic Experiment in Nevada,”
September 8, 2014, http://www.lanl.gov/discover/news-release-archive/2014/September/09.08-nevada-hydrodynamic-
experiment.php.
272 Ibid.
273 Information provided by National Nuclear Security Administration, email, September 25, 2014.
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Nuclear Test Readiness
President Clinton directed DOE to be prepared to conduct a nuclear test within three years of a
decision to do so. Yet a September 2002 report by DOE’s Office of Inspector General found this
ability “at risk.”274 In January 2002 the Nuclear Posture Review briefing called for an unspecified
acceleration of nuclear test readiness, and in March 2002 the Panel to Assess the Reliability,
Safety, and Security of the United States Nuclear Stockpile assessed that “test readiness should be
no more than three months to a year.”275 The FY2003 National Defense Authorization Act, P.L.
107-314, Section 3142, required the Secretary of Energy to report on alternative test readiness
postures and recommend the optimal readiness posture. The resulting report argued that the three-
year posture was increasingly at risk and recommended moving to an 18-month readiness posture
by the end of FY2005.276
The FY2004 Weapons Activities request included $24.9 million to reduce the posture from three
years to 18 months. The National Defense Authorization Act and the Energy and Water
Development Appropriations Act provided the funds requested. Conferees on the latter expected
NNSA to focus on a program that can meet the current 24-month requirement “before requesting
significant additional funds to pursue a more aggressive goal of an 18-month readiness
posture.”277 In contrast, the FY2004 National Defense Authorization Act (P.L. 108-136, §3112)
stated, “Commencing not later than October 1, 2006, the Secretary of Energy shall achieve, and
thereafter maintain, a readiness posture of not more than 18 months for resumption by the United
States of underground tests of nuclear weapons.”
In testimony before the Senate Armed Services Committee on March 24, 2004, NNSA
Administrator Linton Brooks said that NNSA’s goal “is to achieve the 18-month test readiness
posture called for in the Defense Authorization Act.”278 The FY2005 National Defense
Authorization Act provided the full $30.0 million requested for test readiness. In the FY2005
energy and water bill, the House Appropriations Committee recommended reducing the Primary
Assessment Technologies campaign request of $81.5 million, which included $30.0 million for
test readiness, by $15.0 million “to limit the enhanced test readiness initiative to the goal of
achieving a 24-month test readiness posture. The Committee continues to oppose the 18-month
test readiness posture.”279 The FY2005 Consolidated Appropriations Act reduced this campaign
by $7.5 million.

274 U.S. Department of Energy. Office of Inspector General. Office of Audit Services. National Nuclear Security
Administration’s Test Readiness Program,
Audit Report, September 2002, p. 1.
275 Letter report from John Foster, Chairman, Panel to Assess the Reliability, Safety, and Security of the United States
Nuclear Stockpile, to Senator Carl Levin, Chairman, Committee on Armed Services, U.S. Senate, March 15, 2002, p.
ES-2, at http://www.fas.org/nuke/control/ctbt/text/foster01.doc.
276 U.S. Department of Energy. National Nuclear Security Administration. Nuclear Test Readiness. Report to Congress,
April 2003, p. 5-8.
277 U.S. Congress. Committee of Conference. Making Appropriations for Energy and Water Development for the Fiscal
Year Ending September 30, 2004, and for Other Purposes,
H.Rept. 108-357, to accompany H.R. 2754, 108th Congress,
1st Session, 2003, p. 159-160.
278 U.S. Congress. Senate. Committee on Armed Services. Subcommittee on Strategic Forces. Hearing on strategic
forces, March 24, 2004, transcript by FDCH e-Media, Inc. Testimony of Ambassador Linton Brooks, Administrator,
National Nuclear Security Administration.
279 U.S. Congress. House. Committee on Appropriations. Energy and Water Development Appropriations Bill, 2005,
H.Rept. 108-554, to accompany H.R. 4614, 108th Congress, 2nd Session, 2004, p. 116.
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NNSA’s FY2006 test readiness request was $25.0 million “to continue improving the state of
readiness to reach an 18-month test-readiness posture in FY2006.”280 In a Senate Armed Services
Committee hearing on February 15, 2005, Senator John Warner asked Secretary of Energy
Samuel Bodman whether DOE would meet the 18-month test readiness requirement by October
1, 2006. Secretary Bodman replied, “We continue to be committed to that requirement of the law”
and was informed that DOE is on track to meet the October 1 deadline.281 In testimony before the
Senate Appropriations Committee’s Energy and Water Development Subcommittee on April 14,
2005, Ambassador Brooks explained the rationale for the 18-month posture: “Shorter than that,
and you were paying money for readiness you couldn’t use, because the experiment [the nuclear
test] wouldn’t be ready. Longer than that, and you were running the risk of being ready to test to
find out whether you had corrected an important problem, but the test site wasn’t ready.”282 The
House Appropriations Committee continued to favor a 24-month posture and stated that the
Reliable Replacement Warhead program “obviates any reason to move to a provocative 18-month
test readiness posture.”283 The Energy and Water Development Appropriations Act reduced test
readiness funding to $20.0 million; conferees directed DOE to maintain the 24-month posture.
The National Defense Authorization Act also provided $20.0 million; the accompanying
conference report did not address the readiness posture.
For FY2007, NNSA requested $14.8 million for test readiness and noted that the target test
readiness posture for FY2006-FY2011, 24 months, was achieved in FY2005.284 The House
Armed Services Committee’s report on FY2007 defense authorization stated, “While the
committee has no indication of the need to resume underground nuclear testing in the near future,
it does believe that maintaining the 18 month readiness posture as directed by Congress is
important to national security. The committee notes that funding shortfalls have precluded the
Department of Energy from achieving the 18 month readiness posture as required by law.”285 In
the FY2007 Energy and Water Development Appropriations Bill (H.R. 5427), the House provided
the requested amount, and the Senate Appropriations Committee (in S.Rept. 109-274)
recommended providing that amount. NNSA requests no funds under test readiness for FY2008,
noting that the program has achieved its goal of a 24-month readiness posture, current capabilities
will be maintained through other parts of the budget, and “a more forward looking program is
planned.”286 The House Armed Services Committee made no mention of test readiness in its
report, while the Senate Armed Services Committee provided no funds, as requested. The House
Appropriations Committee sharply criticized the decision not to request funds, and added funds:

280 Department of Energy, FY 2006 Congressional Budget Request, Volume 1, p. 93.
281 U.S. Congress. Senate. Committee on Armed Services. Hearing on FY2006 budget request for Atomic Energy
Defense Activities of DOE and NNSA, February 15, 2005, transcript by FDCH e-Media, Inc. Testimony of Samuel
Bodman, Secretary of Energy.
282 U.S. Congress. Senate. Committee on Appropriations. Subcommittee on Energy and Water Development. Hearing
on FY2006 appropriations for NNSA, April 14, 2005, transcript by FDCH e-Media, Inc. Testimony of Ambassador
Linton Brooks, Under-secretary, Nuclear Security, [and] Administrator, National Nuclear Security Administration.
283 U.S. Congress. House. Committee on Appropriations. Energy and Water Development Appropriations Bill, 2006.
H.Rept. 109-86, to accompany H.R. 2419, 109th Congress, 1st Session, 2005, p. 134.
284 Department of Energy, FY 2007 Congressional Budget Request. Volume 1, National Nuclear Security
Administration, p. 97.
285 U.S. Congress. House. Committee on Armed Services. National Defense Authorization Act for Fiscal Year 2007,
H.Rept. 109-452 to accompany H.R. 5122, 109th Congress, 2nd Session, 2006, p. 464.
286 U.S. Department of Energy. Office of Chief Financial Officer. FY 2008 Congressional Budget Request. Volume 1,
National Nuclear Security Administration. DOE/CF-014, February 2007, p. 101. Available at http://www.mbe.doe.gov/
budget/08budget/Content/Volumes/Vol_1_NNSA.pdf.
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The Committee supports the 24-month test readiness posture at the Nevada Test Site and
provides an additional $20,000,000 to restore the funding in the Administration’s budget
request which terminated the activity. The Committee is baffled by the Administration’s
decision to eliminate funding for nuclear test readiness after four budget cycles of insisting
that shortening to an 18-month test readiness posture was required for national security
reasons.... In the fiscal year 2008 budget request, the NNSA proposes what the Committee
believes to be a wasteful investment by allowing the restored test readiness activities to be
degraded.287
Section 3112 of the conference version of H.R. 1585, the FY2008 defense authorization bill,
repealed a provision (P.L. 108-136, §3113; 50 U.S.C. 2528a) requiring an 18-month nuclear test
posture, and required the Secretary of Energy to submit a report on nuclear test readiness every
two years. For test readiness, the FY2008 estimate is $4.9 million and the FY2009 request is
$10.4 million.288 NNSA stated that it had achieved a 24-month test readiness posture in FY2007,
but that “forecasted budget levels resulted in a change in the test readiness posture target to 24 to
36 months.”289 The FY2009 defense authorization bills as passed by the House and as reported by
the Senate Armed Services Committee include the requested amount for test readiness. The
House Appropriations Committee recommended eliminating FY2009 funds for test readiness. It
stated that the “outstanding Stockpile Stewardship program ... has performed better than expected
and has created a technically superior alternative to nuclear testing,” and “the Committee finds no
evidence that nuclear testing would add a useful increment to the immense and expanding body
of weapons knowledge arising from Stockpile Stewardship.”290 The joint explanatory statement
(submitted in lieu of a conference report) on S. 3001, Duncan Hunter National Defense
Authorization Act for FY2009, provided $5.4 million for test readiness.291 According to NNSA,
“The responsibility for the maintenance of infrastructure and physical assets at the NTS
transferred to the RTBF program in FY 2010.”292
Regarding test readiness, NNSA stated in November 2010, “There is no separate funding
designated for Test Readiness in FY2011 nor was there in FY2010. Test Readiness is supported
through the work accomplished in the Stockpile Stewardship Program and specifically by the
experiments that are conducted at the Nevada National Security Site in U1a that exercise the
expertise necessary to resume underground testing if necessary.” NNSA stated in regard to test
readiness posture, “The required posture is to be able to conduct a test in the time frame required
by Presidential Decision Directive 15. Current test readiness is 24 to 36 months. The range is
intentionally vague as it covers a spectrum of possible test scenarios. The specific tests scenarios
are classified.”293 A DOE report of May 2011 provides further details.294

287 U.S. Congress. House. Committee on Appropriations. Energy and Water Development Appropriations Bill, 2008,
H.Rept. 110-185, to accompany H.R. 2641, 110th Congress, 1st Session, 2007, p. 102.
288 Department of Energy, FY2009 Congressional Budget Request, vol. 1, p. 133.
289 Ibid., p. 135.
290 U.S. Congress. House. Committee on Appropriations. Energy and Water Development Appropriations Bill, 2009,
unnumbered committee print, 110th Congress, 2nd Session, June 2008, p. 126.
291 U.S. Congress. House. Committee on Armed Services. Duncan Hunter National Defense Authorization Act for
Fiscal Year 2009,
joint explanatory statement to accompany S. 3001, Committee Print HASC No. 10, 110th Congress,
2nd Session, 2008, p. 799.
292 Department of Energy, FY 2011 Congressional Budget Request, vol. 1, p. 94. RTBF, Readiness in Technical Base
and Facilities, is a major component of the Weapons Activities budget. It funds the operation and maintenance of
weapons complex facilities and the planning and construction of facilities and infrastructure.
293 Information provided to CRS via email by the National Nuclear Security Administration, November 29, 2010.
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Table 2. U.S. Nuclear Tests by Calendar Year
1945-1949 6
1960-1964 202
1980-1984 92
1950-1954 43
1965-1969 231
1985-1989 75
1955-1959 145
1970-1974 137
1990-1992 23

1975-1979
100
Total
1054
Source: U.S. Department of Energy.
Notes: These figures include al U.S. nuclear tests, of which 24 were joint U.S.-UK tests conducted at the
Nevada Test Site between 1962 and 1991. They reflect data on unannounced tests that DOE declassified on
December 7, 1993. They exclude the two atomic bombs that the United States dropped on Japan in 1945. On
June 27, 1994, Secretary O’Leary announced that DOE had redefined three nuclear detonations (one each in
1968, 1970, and 1972) as separate nuclear tests. This table reflects these figures. She also declassified the fact
that 63 tests, conducted from 1963 through 1992, involved more than one nuclear explosive device.
CTBT Pros and Cons
The CTBT is contentious. For a detailed analysis of the case for and against the treaty, see CRS
Report RL34394, Comprehensive Nuclear-Test-Ban Treaty: Issues and Arguments, by Jonathan E.
Medalia. Key arguments include the following:
Can the United States maintain deterrence without testing? The treaty’s supporters hold that the
U.S. stockpile stewardship program can maintain existing, tested weapons without further testing.
Indeed, as of May 2015, the weapons laboratories had completed 19 annual assessments of the
stockpile, with the 20th in progress.295 Treaty supporters claim that these weapons meet any
deterrent needs, so that new types are not needed. Opponents maintain that there can be no
confidence in existing warheads because many minor modifications over time will change them
from tested versions. As a result, some opponents argue that testing is needed to restore and
maintain confidence, while others believe that testing may become needed and the option to
return to testing must not be ruled out. Opponents see deterrence as dynamic, requiring new types
of nuclear weapons to counter new threats, and assert that these weapons must be tested.
Are monitoring and verification capability sufficient? “Monitoring” refers to technical capability;
“verification” to its adequacy to maintain security. Supporters hold that advances in monitoring,
such as the rollout of the International Monitoring System, make it hard for an evader to conduct
undetected tests. They claim that any such tests would be too small to affect the strategic balance.
Opponents see many opportunities for evasion, such as detonating an explosion in a large
underground cavity to muffle its seismic waves. They believe that clandestine tests of even small
weapons could put the United States at a serious disadvantage.
How might the treaty affect nuclear nonproliferation and disarmament? Supporters claim that the
treaty makes technical contributions to nonproliferation, such as limiting weapons programs;
some supporters believe that nonproliferation requires progress toward nuclear disarmament, with
the treaty a key step. They note that all NATO members excepting the United States have ratified
the CTBT. Opponents believe that a strong nuclear deterrent is essential for nonproliferation

(...continued)
294 U.S. Department of Energy. “Nuclear Test Readiness.” Report to Congress, May 2011.
295 Information provided by Los Alamos National Laboratory, email, May 27, 2015.
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because it reduces the incentive for friends and foes alike to build their own nuclear weapons, that
nonproliferation and disarmament are unrelated, and that the international community gives this
nation little credit for its many nonproliferation and disarmament actions.
The National Academy of Sciences Study and Its Critics
In 2012, debate over the CTBT continued as a major study was released and was met by some
criticism. On March 30, 2012, a committee of the National Academy of Sciences (NAS) released
its report, The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States.296
The report was intended to update a similar NAS report issued in 2002297 to reflect more recent
developments. It found considerable improvement in U.S. ability to maintain nuclear weapons
without nuclear-explosive testing as a result of progress in the stockpile stewardship program, and
considerable improvement in U.S. and international ability to detect clandestine nuclear tests as a
result of the rollout of the International Monitoring System and improved technical capabilities. It
stated that further progress is likely in the ability to detect nuclear tests, and that continued and
improved ability to maintain the U.S. nuclear stockpile depends on sustained support. It also
stated that some actions could occur even under a CTBT, such as development of simple nuclear
weapons by states that do not currently possess them, and that not every threat would require a
return to U.S. nuclear testing. Key findings of the report include the following:
• “The technical capabilities for maintaining the U.S. stockpile absent nuclear-
explosion testing are better now than anticipated by the 2002 Report.” (p. 4)
• “Provided that sufficient resources and a national commitment to stockpile
stewardship are in place, the committee judges that the United States has the
technical capabilities to maintain a safe, secure, and reliable stockpile of nuclear
weapons into the foreseeable future without nuclear-explosion testing.” (p. 4)
• “One of the major advances in monitoring in the last 10 years is that most of the
IMS seismic stations are operating now.... The threshold levels for IMS seismic
detection are now well below 1 kt worldwide for fully coupled explosions.” (p. 6)
• In the past 10 years, the IMS radionuclide network has gone from being
essentially non-existent to a nearly fully functional and robust network with new
technology that has surpassed most expectations.” (p. 7)
• A strong national commitment to recruiting and sustaining a high-quality
workforce; recapitalizing aging infrastructure and force structure; and
strengthening the science, engineering, and technology base is essential to
sustaining a safe, secure, and reliable stockpile, as well as necessary explosion-
monitoring capability for the United States.” (p. 8)
• “There is currently no mechanism that would enable Congress to assess whether
the U.S. CTBT safeguards were being fulfilled after entry into force.” (p. 9)

296 National Academy of Sciences. National Research Council. Committee on Reviewing and Updating Technical
Issues Related to the Comprehensive Nuclear Test Ban Treaty. The Comprehensive Nuclear Test Ban Treaty—
Technical Issues for the United States.
Washington, National Academies Press, 2012.
297 National Academy of Sciences. Committee on Technical Issues Related to Ratification of the Comprehensive
Nuclear Test Ban Treaty. Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty. Washington,
National Academy Press, 2002.
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• Russia and China are unlikely to be able to deploy new types of strategic nuclear
weapons that fall outside of the design range of their nuclear-explosion test
experience without several multi-kiloton tests to build confidence in their
performance. Such multi-kiloton tests would likely be detectable (even with
evasion measures) by appropriately resourced U.S. national technical means and
a completed IMS network.” (p. 11)
• “Other States intent on acquiring and deploying modern, two-stage
thermonuclear weapons would not be able to have confidence in their
performance without multi-kiloton testing. Such tests would likely be detectable
(even with evasion measures) by appropriately resourced U.S. national technical
means and a completed IMS network.” (p. 11)
While there has not been a report of similar detail rebutting the 2012 NAS report, there have been
several criticisms. C. Paul Robinson, former Director of Sandia National Laboratories, pointed to
a finding in the report (p. 10) that certain evasion methods “are credible only for device yields
below a few kilotons worldwide and at most a few hundred tons at well-monitored locations.”
Robinson stated that tests at such yield could be of significant value.298 Jack Murphy, a
seismologist with SAIC, commented on seismic monitoring aspects of the NAS report.299 Among
his comments:
• “all of the quantitative monitoring analyses presented in the report simply assume
that detection equals identification.... in general the two thresholds are
significantly different.” (p. 1)
• The NAS report states, “A CTBTO on-site inspection (OSI) would have a high
likelihood of detecting evidence of a nuclear explosion with yield greater than
about 0.1 kilotons, provided that the event could be located with sufficient
precision in advance and that the OSI was conducted without hindrance.”
Murphy responds, “While a specific quantitative value (0.1 kt) is cited for the
yield threshold, the significance of this finding remains unclear. What is the
definition of ‘a high likelihood of detecting evidence’? What is the definition of
‘sufficient precision’ in the location estimate? If it is say better than 5 km, where
would such a precise location estimate come from?” (p. 2)
• The NAS report has a table marked “for the 10% detection probability which the
Committee judges is the largest that would be used by a potential evader for
planning purposes.” Murphy comments, “Once again this equates detection to
identification and monitoring capability. Why 10%? The discussion ignores the
uncertainty associated with the fact that, while the 90% detection thresholds are
generally fairly well constrained by observations, the 10% detection thresholds
are not and basically correspond to extrapolations based on an assumed statistical
distribution model.” (p. 3)

298 Presentation at Heritage Foundation, “Comprehensive Test Ban Treaty: Questions and Challenges,” symposium,
April 10, 2012, http://www.heritage.org/events/2012/04/ctbt.
299 J.R. Murphy, “Comments on the Seismic Monitoring Analyses Presented in the 2012 National Academy of Sciences
Report: ‘The Comprehensive Nuclear Test Ban Treaty—Technical Issues for the United States,” unpublished paper,
2012.
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In addition, some have pointed to the many caveats, qualifications, and imprecise wordings in the
report as indicating considerable uncertainty. For example:
Provided that sufficient resources and a national commitment to stockpile stewardship are in
place,
the committee judges that the United States has the technical capabilities to maintain a
safe, secure, and reliable stockpile of nuclear weapons into the foreseeable future without nuclear-
explosion testing. Sustaining these technical capabilities will require at least … A Strong
Scientific and Engineering Base … A Vigorous Surveillance Program … Modernized Production
Facilities … A Competent and Capable Workforce,” among other things. (p. 4, italics added)
Critics would note that Congress did not provide the full amount requested for Weapons
Activities for FY2012, and that the Administration requested less for FY2013 than it had
indicated in the November 2010 1251 report, calling into question the sufficiency both of
resources and of a national commitment to stockpile stewardship.
“The threshold levels for IMS seismic detection are now well below 1 kt worldwide for fully
coupled explosions
.” (p. 6, italics added) Critics would note that a fully coupled explosion is
perhaps the least likely form of test that a determined evader would use because full coupling
(i.e., with no space between the explosive device and the soil or rock) would readily transmit
seismic signals. Instead, in this view, evaders might use decoupling (detonating a device in a large
cavity so as to muffle the seismic signal), detonating a device in a remote ocean area so that it
would not be attributable to the tester even though it would be detected, or other evasion
scenarios.
“A CTBTO on-site inspection (OSI) would have a high likelihood of detecting evidence of a
nuclear explosion with yield greater than about 0.1 kilotons, provided that the event could be
located with sufficient precision in advance and that the OSI was conducted without hindrance
.”
(p. 8, italics added) In addition to the comments from Murphy, above, critics would note that it is
highly probable that a nation that had conducted a clandestine nuclear test would hinder an OSI in
every way possible, such as by refusing entry for the OSI team, delays, noncooperation, lack of
support, or sabotage. Such tactics would imply that the nation had something to hide, but could
prevent inspectors from finding evidence of a test.
Chronology
09/29/15—The ninth Article XIV Conference on promoting CTBT entry into force is scheduled
to take place in New York.
06/22/15—The fifth CTBT Science and Technology Conference is scheduled to begin in Vienna,
Austria. It is scheduled to conclude on June 26.
05/22/15—The Nuclear Nonproliferation Treaty Review Conference, which began on April 27,
ended without producing a final document.
05/14/15—The CTBTO PrepCom and others concluded a Workshop on Signatures of Medical
and Industrial Isotope Production. The workshop began May 12.
03/20/15—Angola became the 164th state to ratify the CTBT.
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02/24/15—The CTBTO PrepCom and Ecuador concluded an agreement to build two stations of
the International Monitoring System on the Galapagos Islands.
12/09/14—The Vienna Conference on the Humanitarian Impact of Nuclear Weapons was held
December 8 and 9 in Vienna, Austria.
11/03/14—The CTBTO PrepCom sponsored an Integrated Field Exercise in Jordan to test
procedures and technologies for an on-site inspection to detect a clandestine underground nuclear
test. The exercise concluded on December 9, 2014.
09/26/14—The seventh CTBT Ministerial Meeting was held at U.N. Headquarters in New York.
09/04/14—The Republic of the Congo ratified the CTBT.
08/18/14—The CTBTO Preparatory Commission inaugurated a new facility to train personnel
and to test equipment for infrasound (low-frequency sound) and seismic detection of nuclear
explosions.
08/11/14—A report indicated that activity at North Korea’s nuclear test site “has come to a
standstill,” judging from satellite imagery.
06/16-17/14—The CTBTO Preparatory Commission held its 42nd meeting; the next is scheduled
for October 28-30.
06/4-5/14— The G7 summit in Brussels adopted a declaration on nonproliferation and
disarmament calling, among other things, for early entry into force and universalization of the
CTBT.
03/04/14—Niue became the 162nd state to ratify the CTBT.
06/17/13—The Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission
(CTBTO PrepCom) Science and Technology Conference is scheduled for June 17-21.
06/13/13—The CTBTO PrepCom’s 40th session is scheduled for June 13-14. This will be the last
PrepCom of Executive Secretary Tibor Tóth, whose term ends on July 31. His successor, Lassina
Zerbo, takes office the next day.
06/10/13—Fifty years ago, President Kennedy delivered his American University
Commencement Address, in which he proposed a comprehensive test ban treaty and declared a
moratorium on U.S. atmospheric nuclear testing.
06/06/13—The House Armed Services Committee passed H.R. 1960, the FY2014 defense
authorization bill, 59-2. It included an amendment that passed by voice vote fencing certain funds
until the President certifies that no state party to the CTBT has conducted certain nuclear weapon
tests, and barring use of U.S. contributions to the CTBTO PrepCom for lobbying or advocacy in
the United States relating to the CTBT.
04/22/13—The second session of the Preparatory Committee for the 2015 Nuclear Non-
Proliferation Treaty Review Conference was held April 22-May 3. Delegates called for entry into
force of the CTBT and referenced the final document of the 2010 review conference, which
stressed the urgency of entry into force.
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04/08/13—Between April 8 and 14, International Monitoring System stations detected radioactive
isotopes of xenon consistent with the North Korean nuclear test of February 12.
2/12/13—North Korea conducted a nuclear test.
2/08/13—Chad ratified the CTBT.
12/07/12—By a vote of 184 for, 1 against (North Korea), and 3 abstentions, the U.N. General
Assembly adopted a resolution urging countries that have not done so to sign and ratify the
CTBT.
12/05/12—Staff from Los Alamos and Sandia National Laboratories and the Nevada National
Security Site (NNSS) conducted the 27th subcritical experiment, “Pollux,” at NNSS.
10/23/12—Lassina Zerbo was elected to be the next Executive Secretary of the CTBT
Organization Preparatory Commission.
10/22/12—The Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission
began its 39th meeting, which ended October 24.
09/27/12—A group of foreign ministers issued a statement reaffirming their strongest support for
the CTBT.
04/09/12—Niue became the 183rd state to sign the CTBT.
03/30/12—The National Research Council of the National Academy of Sciences released the
unclassified version of its report, The Comprehensive Nuclear Test Ban Treaty—Technical Issues
for the United States.

02/06/12—Indonesia became the 157th state to ratify the CTBT, and the 36th of the 44 Annex 2
states whose ratification is required for entry into force.
12/02/11—The U.N. General Assembly adopted Resolution A/RES/66/64, “Comprehensive
Nuclear-Test-Ban Treaty,” on a vote of 175 for, 1 against (North Korea), and 3 abstentions (India,
Mauritius, Syria). The resolution, among other things, “Stresses the vital importance and urgency
of signature and ratification, without delay and without conditions, in order to achieve the earliest
entry into force of the Comprehensive Nuclear-Test-Ban Treaty.”
10/24/11—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization endorsed a budget of $10.3 million for an integrated field exercise in 2014. This
exercise is intended to improve the organization’s on-site inspection capabilities.
09/23/11—A conference on accelerating CTBT entry into force was held at U.N. headquarters in
New York.
09/20/11—Guinea became the 155th state to ratify the CTBT.
08/29/11—The second International Day Against Nuclear Tests was observed.
06/14/11—Ghana ratified the CTBT.
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06/00/11—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
sponsored a conference, “Comprehensive Nuclear-Test-Ban Treaty: Science and Technology
2011,” in Vienna, Austria, from June 8 to 10.
05/10/11—Ellen Tauscher, Under Secretary of State for Arms Control and International Security,
said, “The Obama Administration is preparing to engage the Senate and the public on an
education campaign that we expect will lead to ratification of the CTBT.”
04/30/11—Foreign ministers from 10 nations issued a statement in support of the CTBT.
03/00/11—The National Institute for Public Policy released a report suggesting that “U.S.
ratification of the CTBT would bring few if any tangible benefits while introducing significant
new risks for U.S. and allied security.”
11/00/10—The Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission
held a simulated on-site inspection in Jordan from November 1 to 12.
10/05/10—Assistant Secretary of State Rose Gottemoeller said, “The Administration prepares for
U.S. Senate reconsideration of the Treaty.”
09/23/10—Twenty-four foreign ministers issued a joint statement on the CTBT calling on “all
States that have not yet done so to sign and ratify the Treaty without delay” and committing
themselves “to make the Treaty a focus of attention at the highest political level.”
09/15/10—NNSA conducted the 24th subcritical experiment, “Bacchus,” at the Nevada Nuclear
Security Site. This was the first such experiment in four years.
08/29/10—U.N. General Assembly resolution 64/35, adopted by consensus on December 3, 2009,
declared this day the International Day Against Nuclear Tests.
05/26/10—Central African Republic and Trinidad and Tobago ratified the CTBT.
05/03/10—At the 2010 NPT Review Conference, Indonesia announced that it “is initiating the
process of the ratification of the Comprehensive Nuclear-Test-Ban Treaty.” Indonesia is one of
the 44 nations that must ratify the treaty for it to enter into force.
05/00/10—The eighth Nuclear Nonproliferation Treaty Review Conference was held May 3-28 at
U.N. headquarters in New York. The final document stated, “The Conference reaffirms the vital
importance of the entry into force of the Comprehensive Nuclear-Test-Ban Treaty as a core
element of the international nuclear disarmament and non-proliferation regime.”
For earlier chronology, see the Appendix.
For Additional Reading
2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear
Weapons, “Final Document,” New York, 2010, http://www.un.org/ga/search/view_doc.asp?
symbol=NPT/CONF.2010/50%20(VOL.I).
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American Association for the Advancement of Science, American Physical Society, and Center
for Strategic and International Studies, Joint Working Group, “Nuclear Weapons in 21st
Century U.S. National Security,” December 2008.
“Arms Control Today 2008 Presidential Q&A: President-elect Barack Obama,” Arms Control
Today, December 2008, pp. 31-36.
Arms Control Association, CTBT at 15: Status and Prospects, report on a conference held
February 17, 2012, at Vienna Center for Disarmament and Non-Proliferation, Vienna, Austria,
October 2012, http://www.armscontrol.org/files/ACA_CTBT_Report_Vienna_2012.pdf.
Australia. Department of Foreign Affairs and Trade. “Berlin Statement by Foreign Ministers on
Nuclear Disarmament and Non-proliferation,” April 30, 2011, http://www.dfat.gov.au/
security/berlin_statement_110430.html.
Bailey, Kathleen, and Robert Barker. “Why the United States Should Unsign the Comprehensive
Test Ban Treaty and Resume Nuclear Testing.” Comparative Strategy. April-June 2003: 131-
138.
Bailey, Kathleen, and Thomas Scheber, The Comprehensive Test Ban Treaty: An Assessment of
the Benefits, Costs, and Risks, National Institute for Public Policy, March 2011, xix + 65 p.,
http://www.nipp.org/CTBT%203.11.11%20electronic%20version.pdf.
Brown, Harold, and John Deutch. “The Nuclear Disarmament Fantasy.” Wall Street Journal,
November 19, 2007, p. 19.
Brumfiel, Geoff, “Isotopes Hint at North Korean Nuclear Test,” Nature, February 3, 2012,
http://www.nature.com/news/isotopes-hint-at-north-korean-nuclear-test-1.9972. [Addresses
De Geer’s article on North Korea]
Center for Security Policy, “Towards a New Deterrent: Analysis and Recommendations for the
Commission on the Strategic Posture of the United States,” 5 p., c. May 2008,
http://www.centerforsecuritypolicy.org/modules/newsmanager/
center%20publication%20pdfs/towards%20a%20new%20deterrent%20516.pdf.
Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty,
“Final Declaration and Measures to Promote the Entry into Force of the Comprehensive
Nuclear-Test-Ban Treaty,” September 27, 2013, 5 p. + app., http://www.ctbto.org/fileadmin/
user_upload/Art_14_2013/Statements/Final_Declaration.pdf.
Congressional Commission on the Strategic Posture of the United States. America’s Strategic
Posture, final report. Washington, DC, United States Institute of Peace Press, May 2009.
Corden, Pierce, and David Hafemeister, “Nuclear Proliferation and Testing: A Tale of Two
Treaties,” Physics Today, April 2014, pp. 41-46.
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Policy, 2009.
Dahlman, Ola, Jenifer Mackby, Svein Mykkeltveit, and Hein Haak, Detect and Deter: Can
Countries Verify the Nuclear Test Ban?, Dordrecht, Netherlands, Springer, 2011, 271 p.
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De Geer, Lars-Erik, “Radionuclide Evidence for Low-Yield Nuclear Testing in North Korea in
April/May 2010,” Science and Global Security, 20 (2012), pp. 1-29,
http://www.tandfonline.com/doi/pdf/10.1080/08929882.2012.652558.
De Geer, Lars-Erik, “The Great 2010 DPRK Nuclear Test Debate: Summarizing the Evidence of
a Low-Yield Nuclear Test Carried out in North Korea in May 2010,” 38 North, May 19, 2015,
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Dodge, Michaela, and Baker Spring, “Keeping Nuclear Testing on the Table: A National Security
Imperative,” Heritage Foundation Backgrounder no. 2770, February 28, 2013,
http://report.heritage.org/bg2770.
Feith, Douglas, Frank Gaffney, James Lyons, and R. James Woolsey, “Obama’s Harmful Nuclear
Illusions,” Washington Post, March 31, 2013, p. 15.
Gallucci, Robert, “Nuclear Shockwaves: Ramifications of the North Korean Nuclear Test,” Arms
Control Today, November 2006.
Gorbachev, Mikhail, “The Nuclear Threat,” Wall Street Journal, January 31, 2007, p. 13.
Gottemoeller, Rose, remarks at the American Bar Association Spring Meeting, International Law
Section, Washington, DC, April 25, 2013, http://translations.state.gov/st/english/texttrans/
2013/04/20130429146553.html#axzz2VLXX3DnP
Graham, Owen, “Consider Tech Risk When Debating Nuclear Test Ban Treaty,” Defense News
(online), June 17, 2012, http://www.defensenews.com/article/20120617/DEFFEAT05/
306170007/Consider-Tech-Risk-When-Debating-Nuclear-Test-Ban-Treaty?odyssey=
nav|head.
Hafemeister, David, “The Comprehensive Test Ban Treaty: Effectively Verifiable,” Arms Control
Today, October 2008.
Hafemeister, David, “Progress in CTBT Monitoring Since Its 1999 Senate Defeat,” Science and
Global Security, no. 15, 2007, pp. 151-183.
Harden, Blaine, “North Korean Nuclear Blast Draws Global Condemnation,” Washington Post,
May 26, 2009, p. 1.
Heller, Arnie, “Enhancing Confidence in the Nation’s Nuclear Stockpile,” Science & Technology
Review, July/August 2010, pp. 4-11.
Hoffman, David, “Supercomputers Offer Tools for Nuclear Testing—and Solving Nuclear
Mysteries,” Washington Post, November 1, 2011, p. 1.
Horovitz, Liviu, “A Detour Strategy for the Test Ban Treaty,” Washington Quarterly, Fall 2011,
pp. 87-99.
“Joint Ministerial Statement on the CTBT,” New York, September 23, 2010, 3 p.,
http://www.ctbto.org/fileadmin/user_upload/public_information/2010/
STATEMENTRev.16.09.pdf.
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Jonas, David, and Thomas Saunders, “The Object and Purpose of a Treaty: Three Interpretive
Methods,” Vanderbilt Journal of Transnational Law, vol. 43, no. 3, May 2010, pp. 565-609.
Joseph, Jofi, “Renew the Drive for CTBT Ratification” Washington Quarterly, April 2009, pp.
79-90, http://www.twq.com/09april/docs/09apr_Joseph.pdf.
Kazakhstan, Embassy of, et al., “Nuclear Weapons Testing: History, Progress, Challenges,”
conference held September 15, 2014, Washington, DC; transcript at
http://www.armscontrol.org/events/Nuclear-Weapons-Testing_History-Progress-Challenges.
Kimball, Daryl, “Learning from the 1999 Vote on the Nuclear Test Ban Treaty,” Arms Control
Today, October 2009, pp. 46-52.
Kimball, Daryl, “Time to Move Forward on the Test Ban Treaty,” Arms Control Today, April
2013, http://www.armscontrol.org/act/2013_04/Focus.
Klug, Foster, and Matthew Pennington, “Photos Show NKorea Nuclear Readiness,” Associated
Press/ABC News, December 28, 2012, http://abcnews.go.com/International/wireStory/ap-
exclusive-photos-show-nkorea-nuclear-readiness-18079671.
Koplow, David, “Nuclear Arms Control by a Pen and a Phone: Effectuating the Comprehensive
Test Ban Treaty without Ratification,” Georgetown Journal of International Law, vol. 46, no.
2, Winter 2015, pp. 475-518, http://www.law.georgetown.edu/academics/law-journals/gjil/
recent/upload/zsx00215000475.PDF.
Kyl, Senator Jon, “Why We Need to Test Nuclear Weapons,” Wall Street Journal, October 21,
2009, p. 23.
Kyl, Senator Jon, and Richard Perle, “Our Decaying Nuclear Deterrent,” Wall Street Journal,
June 29, 2009, p. 13.
Lakshmi, Rama, “Key Indian Figures Call for New Nuclear Tests Despite Deal with U.S.,”
Washington Post, October 5, 2009, p. 7.
Linzer, Dafna, and Thomas Ricks, “U.S. Waits for Firm Information on Nature and Success of
[North Korean Nuclear] Device,” Washington Post, October 11, 2006: 14.
Mathews, Jessica Tuchman, “This Time, Ban the Test,” International Herald Tribune, October
21, 2009.
Monroe, Robert, “Assessing Risks of Comprehensive Test Ban Treaty,” June 15, 2012, video,
http://www.youtube.com/watch?v=h9plbibJ74Y&list=UUPPw4A4ZmhK_e95S2Ka0Xaw&
index=2&feature=plcp.
Monroe, Robert, “The Antiquation of America’s Nuclear Weapons,” Washington Times, March 4,
2013.
Murphy, Jack, “Comments on the Seismic Monitoring Analyses Presented in the 2012 National
Academy of Sciences Report: ‘The Comprehensive Nuclear Test Ban Treaty – Technical
Issues for the United States,’” spring 2012 (technical criticisms of the report by an SAIC
seismologist)
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National Academy of Sciences. “Advances in Nuclear-Test Monitoring and Verification,” briefing
slides by five presenters, September 24, 2012, available via http://cstsp.aaas.org/
content.html?contentid=2507.
National Academy of Sciences. Committee on Technical Issues Related to Ratification of the
Comprehensive Nuclear Test Ban Treaty. Technical Issues Related to the Comprehensive
Nuclear Test Ban Treaty.
Washington, National Academies Press, 2002. http://www.nap.edu/
catalog.php?record_id=10471.
National Academy of Sciences, National Research Council, Committee on Reviewing and
Updating Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty, The
Comprehensive Nuclear Test Ban Treaty—Technical Issues for the United States,
Washington,
National Academies Press, 2012, http://www.nap.edu/catalog.php?record_id=12849. [updates
2002 report]
O’Leary, Hazel, “New Evidence for the Nuclear Test-Ban Treaty,” San Diego Union-Tribune,
April 19, 2012, http://www.utsandiego.com/news/2012/apr/19/new-evidence-for-the-nuclear-
test-ban-treaty/.
Pabian, Frank, and Siegfried Hecker, “Contemplating a Third Nuclear Test in North Korea,”
Bulletin of the Atomic Scientists (online edition), August 6, 2012.
Perfilyev, Nikita, “Keeping the Nuclear-Test-Ban Treaty Alive,” The Diplomat, May 5, 2015,
http://thediplomat.com/2015/05/keeping-the-nuclear-test-ban-treaty-alive/.
Preparatory Committee for the 2015 Review Conference of the Parties to the Treaty on the Non-
Proliferation of Nuclear Weapons, Second Session (April 22-May 3, 2013), “Comprehensive
Nuclear-Test-Ban Treaty,” Working paper submitted by the members of the Non-Proliferation
and Disarmament Initiative (Australia, Canada, Chile, Germany, Japan, Mexico, the
Netherlands, Poland, Turkey and the United Arab Emirates), March 6, 2013,
NPT/CONF.2015.PC.II/WP-1, http://papersmart.unmeetings.org/media/1104226/
NPTCONF.2015PC.IIWP.1.pdf
Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, website,
http://www.ctbto.org.
Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Annual
Report 2013, June 2014, c. 90 p., http://www.ctbto.org/fileadmin/user_upload/pdf/
Annual_Report_2013/English/AR2013-English-Opening.pdf.
Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, “CTBTO detects
radioactivity consistent with 12 February announced North Korean nuclear test,” press
release, April 23, 2013, http://www.ctbto.org/press-centre/press-releases/2013/ctbto-detects-
radioactivity-consistent-with-12-february-announced-north-korean-nuclear-test/.
Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, IFE14 [Integrated
Field Exercise 2014] home page, http://www.ctbto.org/specials/integrated-field-exercise-
2014/.
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Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty, CTBTO Spectrum
(journal), August 2014, http://www.ctbto.org/publications/spectrum-publication/spectrum-
issues-2012-and-onward/issue-22-august-2014/.
“Project for the Comprehensive Nuclear Test Ban Treaty,” website sponsored by the Arms
Control Association, http://projectforthectbt.org/.
Ramaker, Jaap, Jenifer Mackby, Peter Marshall, and Robert Geil, The Final Test: A History of the
Comprehensive Nuclear-Test-Ban Treaty Negotiations, Vienna, Austria, Provisional Technical
Secretariat of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
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Richards, Paul, “Forensic Seismology and CTBT Verification,” CTBTO Spectrum, January 2007,
pp. 1, 6, 19.
Ringbom, A., et al., “Radioxenon Detections in the CTBT International Monitoring System
Likely Related to the Announced Nuclear Test in North Korea on February 12, 2013, Journal
of Environmental Radioactivity
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Russian Federation. Ministry for Atomic Energy and Ministry of Defense. USSR Nuclear
Weapons Tests and Peaceful Nuclear Explosions, 1949 through 1990. 1996. 63 p.
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Sanger, David, and Choe Sang-Hun, “North Korea Confirms It Conducted 3d Nuclear Test,” New
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Schneidmiller, Chris, “As Obama Prepares to Push Nuclear Test Ban, Technological Basis Still
Debated,” Global Security Newswire, July 15, 2011, and “Senate Decision Key to Future of
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Schoeppener, Ulrich Kuhn, “Improve the Nuclear Test Monitoring system,” Bulletin of the Atomic
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Shultz, George, William Perry, Henry Kissinger, and Sam Nunn, “A World Free of Nuclear
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Shultz, George, William Perry, Henry Kissinger, and Sam Nunn, “Toward a Nuclear-Free World,”
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Shultz, George, William Perry, Henry Kissinger, and Sam Nunn, “How to Protect Our Nuclear
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Spring, Baker, Restoring the Role of the Nation-State System in Arms Control and Disarmament,
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Sokolski, Henry, and Gary Schmitt, “Advice for the Nuclear Abolitionists,” Weekly Standard,
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UK Prime Minister’s Office. “UK-France Summit 2010 Declaration on Defence and Security Co-
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U.S. Department of Energy. National Nuclear Security Administration. Nuclear Test Readiness,
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U.S. Department of Energy. National Nuclear Security Administration, “Summary of
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U.S. Secretary of Energy, Secretary of Defense, and Secretary of State. “National Security and
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http://www.nnsa.doe.gov/docs/factsheets/2007/NA-07-FS-04.pdf.
U.S. Department of State. “Remarks at the Friends of the Comprehensive Nuclear-Test-Ban
Treaty Ministerial,” John Kerry, Secretary of State, United Nations Headquarters, New York City,
September 26, 2014, http://www.state.gov/secretary/remarks/2014/09/232219.htm.
U.S. White House. Office of the Press Secretary. “Joint Statement Between President George W.
Bush and [Indian] Prime Minister Manmohan Singh,” July 16, 2005.
Vienna Conference on the Humanitarian Impact of Nuclear Weapons, “Report and Summary of
Findings of the Conference,” December 8-9, 2014, http://www.bmeia.gv.at/fileadmin/
user_upload/Zentrale/Aussenpolitik/Abruestung/HINW14/HINW14_Chair_s_Summary.pdf.
Walter, Katie, “Sleuthing Seismic Signals,” Science & Technology Review, March 2009, pp. 4-12.
Weapons of Mass Destruction Commission, Weapons of Terror: Freeing the World of Nuclear,
Biological and Chemical Arms. June 2006, 227 p. http://www.wmdcommission.org/files/
Weapons_of_Terror.pdf.
“The United States-Indonesia Comprehensive Partnership,” speech by H.E. Dr. N. Hassan
Wirajuda, Minister for Foreign Affairs, Republic of Indonesia, at a breakfast forum with the
Carnegie Endowment for International Peace and USINDO, Washington, DC, June 8, 2009.
Woolsey, R. James, and Keith Payne, “Reconsidering the Comprehensive Test Ban Treaty: It’s an
Ineffectual Gesture That Could Do More Harm Than Good,” National Review Online,
September 8, 2011, http://www.nationalreview.com/articles/276530/reconsidering-
comprehensive-test-ban-treaty-r-james-woolsey.
Zhang, Miao, and Lianxing Wen, “Seismological Evidence for a Low-Yield Nuclear Test on 12
May 2010 in North Korea,” Seismological Research Letters, Vol, 86, no. 1, January/February
2015, pp. 1-8.
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Appendix. Chronology, 1992-2009
09/23/92—The United States conducted its most recent nuclear test, “Divider.”
10/02/92—President Bush signed the FY1993 Energy and Water Development Appropriations
Act, P.L. 102-377; Section 507 restricted U.S. nuclear testing.
10/13/92—Russia announced an extension of its test moratorium at least to mid-1993.
01/13/93—President François Mitterrand said France would extend its test moratorium as long as
the United States and Russia did.
04/24/93—At the Vancouver summit, Presidents Clinton and Yeltsin agreed that negotiations on a
multilateral test ban should begin soon.
07/03/93—President Clinton announced his plan to continue the test moratorium through
September 1994 as long as no other nation tests.
08/10/93—The Conference on Disarmament (CD) gave its Ad Hoc Committee on a Nuclear Test
Ban a mandate to negotiate a CTBT.
10/05/93—China held the world’s first nuclear test since September 1992.
01/25/94—The Conference on Disarmament opened its 1994 session in Geneva, with negotiation
of a CTBT its top priority.
03/15/94—The United States extended its test moratorium through September 1995.
06/10/94—China conducted an underground nuclear test.
09/26/94—President Yeltsin, in an address to the U.N. General Assembly, said, “Russia favors
signing this treaty [the CTBT] next year.”
10/07/94—China conducted an underground nuclear test.
01/24/95—President Clinton said in his State of the Union address, “The United States will lead
the charge to extend indefinitely the Nuclear Non-Proliferation Treaty [and] to enact a
comprehensive nuclear test ban.”
01/30/95—President Clinton continued the U.S. moratorium until a CTBT enters into force,
assuming it is signed before September 30, 1996.
05/11/95—The Nuclear Non-Proliferation Treaty Review and Extension Conference agreed to
extend that treaty indefinitely, and by reference called for completing CTBT negotiations not later
than 1996.
05/15/95—China conducted a nuclear test, its fourth since September 1992.
06/13/95—President Jacques Chirac announced that France would conduct eight nuclear tests in
the South Pacific between September 1995 and May 1996.
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08/04/95—The Senate tabled, 56 to 44, an amendment by Senator Exon and others to delete $50
million for conducting hydronuclear tests (those producing extremely low nuclear yield). The
amendment was to S. 1026, the FY1996 National Defense Authorization Bill.
08/10/95—France announced that once it completed its nuclear test program, it would support a
CTBT that bans all nuclear tests of any yield.
08/11/95—President Clinton announced his decision to pursue a “true zero yield” CTBT, banning
all nuclear tests regardless of yield, accompanied by six “safeguards” to assure confidence in U.S.
nuclear weapons under a CTBT.
08/17/95—China conducted a nuclear test, its fifth since September 1992.
09/05/95—France conducted a nuclear test, its first since 1991.
12/13/95—A U.N. General Assembly resolution, passed 85-18, “strongly deplores” current
nuclear testing and “strongly urges” an immediate end to testing.
01/23/96—In his State of the Union Address, President Clinton stated, “We must end the race to
create new nuclear weapons by signing a truly comprehensive nuclear test ban treaty—this year.”
01/27/96—France held the sixth nuclear test in its test series.
01/29/96—President Chirac announced “the final end to French nuclear tests.”
03/07/96—The Washington Times reported U.S. intelligence agencies have ambiguous evidence
that Russia may have conducted a nuclear test in January 1996.
04/19/96—President Yeltsin formally endorsed a zero-yield CTBT and reserved the right to
resume testing if Russia’s supreme interests are threatened. The next day, the Group of Seven plus
Russia expressed their commitment to complete and sign a zero-yield CTBT by September 1996.
05/28/96—Ambassador Jaap Ramaker of the Netherlands, chairman of the CD’s Ad Hoc
Committee on a Nuclear Test Ban, tabled a draft text of a CTBT incorporating compromises on
key outstanding issues.
06/04/96—France and the United States signed an agreement to share information relevant to
maintaining nuclear weapons.
06/08/96—China held a nuclear test and declared that after one more test it would join an
international moratorium on nuclear explosions.
06/20/96—India stated it would not sign a CTBT unless the five declared nuclear weapon states
agreed to a timetable to give up their nuclear weapons.
06/26/96—The Senate tabled, 53-45, an amendment by Senators Kyl and Reid to the FY1997
National Defense Authorization Bill to permit U.S. nuclear testing after September 30, 1996,
under certain conditions if the Senate had not given its advice and consent to ratification of a
CTBT.
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07/23/96—The United States and Russia announced their joint support for the existing draft
CTBT. While this draft did not fully satisfy either nation, they saw it as acceptable and the only
route to achieving a CTBT in 1996.
07/29/96—China conducted what it said would be its last nuclear test, and pledged to begin a
moratorium on testing on July 30.
08/07/96—China and the United States reportedly reached an agreement on modifying the draft
treaty so as to resolve China’s concerns over CTBT verification, clearing the way for China to
support the treaty.
08/20/96—India vetoed the draft CTBT in the CD, barring the treaty from going to the U.N.
General Assembly as a CD document.
08/23/96—Australia asked the U.N. General Assembly to begin consideration of the draft CTBT
on September 9.
09/10/96—The U.N. General Assembly adopted, 158 to 3 (with 5 abstentions and 19 nations not
voting), the draft CTBT negotiated at the CD.
09/24/96—The CTBT was opened for signing; President Clinton and others signed.
11/20/96—The Preparatory Commission for the Comprehensive Test Ban Treaty Organization
(CTBTO) began its first meeting.
07/02/97—The Department of Energy conducted its first subcritical experiment, “Rebound,” at
the Nevada Test Site. It conducted one more in 1997.
08/28/97—The Washington Times reported Administration officials as saying Russia may have
conducted a nuclear explosion on August 16.
09/22/97—President Clinton submitted the CTBT to the Senate for its advice and consent to
ratification.
11/04/97—The Washington Post reported the Administration formally dropped its claim that a
seismic event of August 16, 1997, was a Russian nuclear test.
01/21/98—Senator Jesse Helms, in a letter to President Clinton, said “the CTBT is very low on
the [Senate Foreign Relations] Committee’s list of priorities.”
01/27/98—In his State of the Union address, President Clinton asked the Senate to approve the
CTBT this year and announced that four former Chairmen of the Joint Chiefs of Staff had
endorsed the treaty.
03/25/98—The Department of Energy conducted its third subcritical experiment, “Stagecoach,”
at the Nevada Test Site. It conducted two more in 1998.
04/06/98—Britain and France became the first declared nuclear weapon states to ratify the CTBT,
depositing instruments of ratification with the United Nations.
05/11/98—Prime Minister Vajpayee announced India conducted three nuclear tests.
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05/13/98—India announced that it conducted two nuclear tests.
05/28/98—Pakistan announced that it conducted five nuclear tests.
05/30/98—Pakistan announced that it conducted one nuclear test.
06/05/98—The foreign ministers of China, France, Russia, the United Kingdom, and the United
States, in a joint communique, condemned the Indian and Pakistani nuclear tests, urged India and
Pakistan to refrain from weaponizing or deploying nuclear weapons, and called on them to adhere
to the CTBT “immediately and unconditionally.”
09/23/98—Pakistan’s Prime Minister, Nawaz Sharif, in an address to the United Nations, said his
nation would adhere to the CTBT if other nations lifted economic sanctions, as long as India
refrained from testing.
12/00/98—Secretary of Energy Bill Richardson and Secretary of Defense William Cohen
submitted the third annual nuclear stockpile certification memorandum to the President stating,
“The nuclear stockpile has no safety or reliability concerns that require underground testing at
this time.”
02/09/99—The Department of Energy conducted its sixth subcritical experiment, “Clarinet,” at
the Nevada Test Site. It conducted two more in 1999.
05/25/99—The Cox Committee, in its report, stated its belief that China may be continuing to
conduct underground nuclear tests.
07/20/99—In separate press conferences, President Clinton and nine Senators urged the Senate to
consider the CTBT. A survey found 82% of Americans want the treaty approved. All 45
Democratic Senators wrote to Senator Helms urging him to hold hearings on the treaty and to
report it to the Senate.
07/26/99—Responding to the July 20 letter, Senator Helms stated that “I do not share your
enthusiasm for this treaty” and that the Senate Foreign Relations Committee would consider it
after amendments to the ABM Treaty and the Kyoto Protocol.
09/30/99—Senator Lott proposed a unanimous-consent request that would bring the CTBT to the
Senate floor for 10 hours of debate beginning October 6, and then to a vote.
10/08/99—(1) States that had ratified the CTBT ended a three-day conference on expediting entry
into force. (2) The Senate began debate on the treaty.
10/11/99—President Clinton wrote to Senators Lott and Daschle to request that a vote on the
CTBT be delayed.
10/13/99—The Senate rejected the CTBT, 48 for, 51 against, 1 present.
01/28/00—Secretary of State Albright announced that Gen. John Shalikashvili (ret.) would head
the Administration’s effort to achieve bipartisan support for CTBT ratification, but the State
Department indicated the Administration did not expect to seek Senate approval of the treaty in
2000.
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02/04/00—DOE conducted the ninth U.S. subcritical experiment, “Oboe 3.” It held four more in
2000.
02/04/00—Russia announced that it conducted seven subcritical experiments between September
23, 1999, and January 8, 2000.
06/30/00—Russia ratified the CTBT.
11/03/00—Russia announced that it completed its fifth and final series of subcritical experiments
for 2000 at Novaya Zemlya during the week of October 30.
01/17/01—Colin Powell, as nominee for Secretary of State, said the Administration would not
ask for CTBT ratification in this session of Congress.
03/04/01—The New York Times reported U.S. intelligence experts were divided on whether
Russia had conducted clandestine tests over the past several years.
06/26/01—The House Appropriations Committee declined to add funds to the FY2002 Energy
and Water Development Appropriations Bill to increase nuclear test readiness, arguing the
Secretary of Defense, President, Armed Services Committees, and Congress must first request or
approve these funds.
09/26/01—The National Nuclear Security Agency (NNSA) held the 14th U.S. subcritical
experiment, “Oboe 8.” It conducted one more in 2001.
11/11/01—The Conference on Facilitating the Entry into Force of the CTBT began on this date at
U.N. headquarters in New York and ended November 13.
02/15/02—NNSA held the 16th U.S. subcritical experiment, and the first with UK participation,
“Vito.” It conducted three more subcritical experiments, without UK participation, in 2002.
05/10/02—The House passed H.R. 4546, the Bob Stump National Defense Authorization Act for
FY2003; it called for DOE to achieve the ability to conduct a nuclear test within a year of a
presidential direction to test.
07/31/02—The National Academy of Sciences issued a report asserting that the main technical
concerns raised in regard to the CTBT are manageable.
09/26/02—NNSA held the 19th U.S. subcritical experiment, “Rocco.”
02/00/03—A House Policy Committee report recommended “a test readiness program that could
achieve an underground diagnostic [nuclear] test within 18 months”; the Bipartisan Congressional
Task Force on Nonproliferation urged President Bush “not to resume nuclear weapons testing.”
05/22/03—The Senate passed, 98-1, S. 1050, the FY2004 National Defense Authorization Bill.
Section 3132 directed the Secretary of Energy to achieve by October 1, 2006, and to maintain
thereafter, the ability to conduct a nuclear test within 18 months of a decision to test, unless the
Secretary determines that a different number of months is preferable.
09/00/03—A conference on facilitating the CTBT’s entry into force was held in Vienna, Austria,
September 3-5.
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09/19/03—NNSA held the 20th U.S. subcritical experiment, “Piano.”
10/30/03—The U.N. General Assembly’s First Committee (Disarmament and International
Security) approved a draft resolution, “A Path to Total Elimination of Nuclear Weapons,” 146-2,
with 16 abstentions. A provision stressed the importance of achieving early entry into force of the
CTBT. The United States and India voted no; the U.S. representative stated that he did so because
of U.S. opposition to the CTBT.
11/00/03—The 21st meeting of the CTBTO Preparatory Commission was held November 10-13
in Vienna, Austria.
12/08/03—The U.N. General Assembly adopted, 164-2, with 2 abstentions, a resolution, “A Path
to Total Elimination of Nuclear Weapons.”
01/06/04—Libya became the 109th nation to ratify the CTBT.
05/25/04—NNSA held the 21st U.S. subcritical experiment, “Armando.”
06/20/04—In a joint statement, India and Pakistan agreed to reaffirm their unilateral moratoria on
nuclear testing, barring extraordinary events, and to establish a dedicated and secure hotline
between the two foreign secretaries.
06/00/04—The 22nd meeting of the CTBTO Preparatory Commission was held June 22-24 in
Vienna, Austria.
09/24/04—Foreign ministers from 42 nations issue a statement calling entry into force of the
CTBT “more urgent today than ever before.”
12/03/04—The U.N. General Assembly adopted, 177-2, with 4 abstentions, a resolution,
“Comprehensive Nuclear-Test-Ban Treaty.”
02/10/05—North Korea declared, “We ... have manufactured nukes for self-defense to cope with
the Bush Administration’s evermore undisguised policy to isolate and stifle the DPRK.”
03/10/05—The European Parliament passed a resolution that, among other things, “reiterates its
call for the USA ... to sign and ratify the CTBT.”
05/00/05—At the Nuclear Nonproliferation Treaty Review Conference, held May 2-27, some
nations criticized the United States for not ratifying the CTBT.
05/16/05—The New York Times reported that on May 15, National Security Advisor Stephen
Hadley stated, “Action would have to be taken” if North Korea conducted a nuclear test.
08/29/05—Egyptian Foreign Minister Ahmed Aboul Gheit reportedly stated that Egypt would not
ratify the CTBT until Israel joins the NPT.
09/00/05—A conference, Facilitating the Entry into Force of the Comprehensive Nuclear Test
Ban Treaty, was held September 21 to 23 at U.N. headquarters in New York.
11/00/05—The 25th session of the Preparatory Commission for the Comprehensive Nuclear-Test-
Ban Treaty Organization was held November 14 to 18.
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12/08/05—The U.N. General Assembly adopted, 168-2, a resolution on nuclear disarmament that,
among other things, urged nations to ratify the CTBT.
2/23/06—The United States and United Kingdom conducted a subcritical experiment,
“Krakatau,” at the Nevada Test Site.
06/00/06—The 26th meeting of the Preparatory Commission for the Comprehensive Nuclear Test
Ban Treaty Organization was held June 20-23.
08/30/06—The United States conducted its 23rd subcritical experiment, “Unicorn,” at the Nevada
Test Site.
09/20/06—Fifty-nine foreign ministers called on states that have not done so to ratify the treaty.
09/28/06—Representative Tauscher introduced H.Res. 1059, calling on the Senate to give its
advice and consent to CTBT ratification.
10/03/06—North Korea declared that it will conduct a nuclear test.
10/09/06—North Korea claimed to have conducted its first nuclear test; most reports placed the
explosive yield of the test at one kiloton or less.
10/16/06—The United States confirmed that the North Korean event of October 9 was a nuclear
test.
11/17/06—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 27th meeting.
01/04/07—Four former government officials urged “[i]nitiating a bipartisan process with the
Senate ... to achieve ratification of the Comprehensive Test Ban Treaty.”
01/31/07—Mikhail Gorbachev called on nuclear weapon states to ratify the CTBT.
03/29/07—The Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission
certified the 200th and 201st International Monitoring System stations.
06/04/07—The Senate Armed Services Committee reported S. 1547, FY2008 National Defense
Authorization Act. Section 3122, Sense of Congress on the Nuclear Nonproliferation Policy of
the United States and the Reliable Replacement Warhead Program, included a provision, “the
Senate should ratify the Comprehensive Nuclear-Test-Ban Treaty.”
06/04/07—The United States paid $10.0 million toward the International Monitoring System to
the Comprehensive Test Ban Treaty Organization Preparatory Commission.
06/22/07—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 28th meeting.
09/00/07—The United Nations held the fifth conference on facilitating CTBT entry into force on
September 17 and 18 in Vienna, Austria.
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10/24/07—Senator Jon Kyl delivered a speech critical of the CTBT and of Section 3122 of H.R.
1585, the FY2008 National Defense Authorization Act, expressing the sense of Congress that the
Senate should ratify the CTBT. Senator Kyl included a letter signed by 41 Senators opposing the
treaty and Section 3122.
11/14/07—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 29th meeting.
11/19/07—Former Secretary of Defense Harold Brown and former Director of Central
Intelligence John Deutch suggested a five-year renewable CTBT in lieu of the current treaty.
12/05/07—By a vote of 176 for, 1 against (United States), and 4 abstentions, the U.N. General
Assembly adopted resolution A/RES/62/59 stressing the importance of achieving the earliest
entry into force of the CTBT.
11/26/07—The conference report on H.R. 1585, the FY2008 defense authorization bill, was
ordered to be printed. The bill provided for biennial reports on U.S. nuclear test readiness and
dropped a provision in the Senate bill expressing the sense of Congress that “the Senate should
ratify” the CTBT.
12/17/07—Representative Tauscher introduced H.Res. 882, expressing the sense of the House
that the Senate should initiate a bipartisan process to give its advice and consent to ratification of
the CTBT.
01/29/08—Colombia, one of the Annex 2 states that must ratify the CTBT for it to enter into
force, became the 144th nation to ratify the treaty.
02/25/08—The United States paid $23.8 million to the Comprehensive Nuclear-Test-Ban Treaty
Preparatory Commission, restoring its voting rights in the commission.
05/27/08—Senator John McCain said he would “tak[e] another look at the Comprehensive Test
Ban Treaty to see what can be done to overcome the shortcomings that prevented it from entering
into force.”
06/26/08—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 30th meeting.
08/19/08—Iraq became the 179th nation to sign the CTBT.
09/00/08—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization conducted a large-scale Integrated Field Exercise in Kazakhstan to simulate a
complete on-site inspection.
09/24/08—A joint ministerial statement urging states that have not done so to sign and ratify the
CTBT was launched; as of December 12, 2008, 96 nations had associated themselves with the
statement.
11/21/08—Lebanon became the 148th nation to ratify the CTBT.
01/13/09—In her answers to questions for the record prepared for her confirmation hearing of this
date, Secretary of State-designate Hillary Clinton said, “The President-Elect and I are both
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strongly committed to Senate approval of the CTBT and to launching a diplomatic effort to bring
on board other states whose ratifications are required for the treaty to enter into force.”
04/05/09—In a speech in Prague, President Obama said, “my administration will immediately
and aggressively pursue U.S. ratification of the Comprehensive Test Ban Treaty.”
05/25/09—North Korea announced that it had conducted a nuclear test, its second.
06/08/09—Foreign Minister Hassan Wirajuda of Indonesia said that his nation would
“immediately” ratify the CTBT once the United States did so.
06/10/09—An international scientific conference was held in Vienna, Austria, June 10-12 to
present the results of the International Scientific Studies project.
09/00/09—A conference on CTBT entry into force, pursuant to Article XIV of the treaty, was
held at U.N. headquarters in New York on September 24 and 25.

Author Contact Information

Jonathan E. Medalia

Specialist in Nuclear Weapons Policy
jmedalia@crs.loc.gov, 7-7632


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