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

Jonathan Medalia
Specialist in Nuclear Weapons Policy
December 7, 2011
Congressional Research Service
7-5700
www.crs.gov
RL33548
CRS Report for Congress
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epared for Members and Committees of Congress

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 U.N.
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, the Administration focused its efforts in 2010 on securing Senate
advice and consent to ratification of the New Strategic Arms Reduction Treaty (New START).
The Administration has indicated it wants to begin a CTBT “education” campaign with a goal of
securing Senate advice and consent to ratification, but there have been no hearings on the treaty
in the 111th or 112th Congresses. As of December 2011, 182 states had signed the CTBT and 156,
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. Seven conferences
have been held to facilitate entry into force, most recently on September 23, 2011.
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 and 2009. Since 1997, the United States has held 26
“subcritical experiments” at the Nevada National Security Site, most recently in February 2011,
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 since 1998.
Congress addresses nuclear weapon issues in the annual National Defense Authorization Act and
the Energy and Water Development Appropriations Act. It considers the Stockpile Stewardship
Program (listed as Weapons Activities), which seeks to maintain nuclear weapons without testing;
the FY2011 appropriation was $6.896 billion, and the FY2012 request is $7.630 billion. Congress
considers a U.S. contribution to a global system to monitor possible nuclear tests. The FY2012
request is $33.0 million, with another $7.5 million requested for projects to improve the CTBT
verification regime.
This report will be updated occasionally. This version reflects Indonesia’s ratification of the treaty
on December 6, 2011, and makes other updates throughout. CRS Report RL34394,
Comprehensive Nuclear-Test-Ban Treaty: Issues and Arguments, by Jonathan Medalia, presents
CTBT pros and cons in detail. CRS Report R40612, Comprehensive Nuclear-Test-Ban Treaty:
Updated “Safeguards” and Net Assessments
, by Jonathan Medalia, discusses safeguards—
unilateral steps to maintain U.S. nuclear security consistent with nuclear testing treaties—and
their relationship to the CTBT. CRS Report R41908, Energy and Water Development: FY2012
Appropriations
, coordinated by Carl E. Behrens, 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 ................................................................................................... 11
The October 2006 Nuclear Test............................................................................................... 11
The May 2009 Nuclear Test .................................................................................................... 13
The CTBT: Negotiations, Provisions, Entry into Force, CTBTO Budget ..................................... 15
CTBT Negotiations and the Nuclear Nonproliferation Treaty ................................................ 15
Key Provisions of the CTBT ................................................................................................... 18
International Efforts on Behalf of Entry into Force................................................................. 21
Budget of the CTBTO Preparatory Commission..................................................................... 24
Stockpile Stewardship.................................................................................................................... 25
CTBT Pros and Cons ..................................................................................................................... 36
Chronology .................................................................................................................................... 37
For Additional Reading.................................................................................................................. 40

Tables
Table 1. U.S. Nuclear Tests by Calendar Year ............................................................................... 36

Appendixes
Appendix. Chronology, 1992-2006 ............................................................................................... 46

Contacts
Author Contact Information........................................................................................................... 52

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

Most Recent Developments
On December 6, 2011, Indonesia ratified the CTBT. It is one of 44 states that must ratify for the
treaty to enter into force and the first of these states to do so since January 2008; 36 of the 44
have now ratified. On December 2, by a vote of 175 for, 1 against (North Korea), and 3
abstentions, the U.N. General Assembly adopted a resolution stressing the importance of “the
earliest entry into force” of the CTBT. On September 23, at U.N. Headquarters, states that had
ratified the CTBT, along with those that had signed it, held a Conference on Facilitating the Entry
into Force of the Comprehensive Nuclear-Test-Ban Treaty. At the conference, Ellen Tauscher,
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.” On September 8, the
National Review Online published an article by R. James Woolsey and Keith Payne,
“Reconsidering the Comprehensive Test Ban Treaty: It’s an Ineffectual Gesture That Could Do
More Harm Than Good.” On June 8-10, a conference, “CTBT: Science and Technology 2011,”
organized by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization, was held in Vienna. A goal was to “[d]iscuss advances in science and technology
relevant to test ban verification.” In March, the National Institute for Public Policy released a
report, The Comprehensive Test Ban Treaty: An Assessment of the Benefits, Costs, and Risks,
which concluded, “U.S. ratification of the CTBT would bring few if any tangible benefits while
introducing significant new risks for U.S. and allied security.”
History
While the Comprehensive Nuclear-Test-Ban Treaty (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

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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about U.S. ability to monitor the two unratified 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 December
2011, 182 states had signed it and 156 had ratified.2
National Positions on Testing and the CTBT
United States: 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
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

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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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
force of the Comprehensive Nuclear-Test-Ban Treaty and call upon all States to sign and ratify

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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the Treaty.”7 John Bolton, the U.S. Ambassador to the U.N., 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 a 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, 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 And Senator Jon
Kyl, who led the opposition to the CTBT in 1999, reportedly said, “I will lead the charge against
it and I will do everything in my power to see that it is defeated.”21
The time line 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 would replace, 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.22 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.23 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, 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.”24
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.
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.25 The United Kingdom and France are also pooling stockpile

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 “Push for Controversial Nuke Treaty Expected Next Spring at the Earliest,” The Cable, October 2, 2009.
22 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.
23 Mary Beth Sheridan and Walter Pincus, “Sources: $4 Billion Bid to Save START,” Washington Post, November 13,
2010, p. 3.
24 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.
25 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.
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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.26
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.”27 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.
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.”28 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.”29
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.30 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.”31 In September 2009, Dmitry Medvedev, president of the Russian

26 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.
27 Craig Whitney, “France to Back Ban After Its Atom Tests,” New York Times, August 11, 1995, p. 3.
28 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.
29 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.
30 “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.
31 “Russia Supports CTBT as Key Element of Nuclear Non-Proliferation—FM,” Itar-Tass, November 12, 2007.
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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.”32
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.33
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.”34
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.”35 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 December 2011, China had not ratified the treaty.
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

32 United Nations. Security Council. 6191st meeting, September 24, 2009, S/PV.6191, provisional version, p. 7.
33 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.
34 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.
35 “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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India has a proven capability for a weaponised nuclear programme.”36 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.”37 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.”38 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.”39
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.”40 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.”41 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.”42 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.”43 According to a report of November 2007, when some
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

36 India. Ministry of External Affairs. Press statement, New Delhi, May 11, 1998, at http://nuclearweaponarchive.org/
India/Indianofficial.txt.
37 India. Ministry of External Affairs. “Joint Statement, India-Pakistan Expert-Level Talks on Nuclear CBMs
[Confidence-Building Measures],” June 20, 2004.
38 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.
39 “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.
40 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.
41 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.
42 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.
43 “India Not to Accept Any Legal Binding on N-Testing,” Press Trust of India Limited, January 13, 2007.
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out a nuclear test arises in future, there is nothing in the agreement which prevents us from
carrying out tests.”44 (See CRS Report RL33529, India: Domestic Issues, Strategic Dynamics,
and U.S. Relations
, coordinated by K. Alan Kronstadt.)
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.”45 In response, other Indian officials claimed that the thermonuclear tests were
successful, so no further tests were needed.46 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.47 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.48 As
of December 2011, 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
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.”49
In August 2000, President Pervez Musharraf said the time was not ripe to sign the CTBT because
so doing could destabilize Pakistan.50 In September 2005, Pakistan reportedly said it would not be
the first nation in the region to resume nuclear testing.51 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.52 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

44 “Indian Lawmakers Attack U.S. Nuclear Deal,” Global Security Newswire, November 29, 2007.
45 “No CTBT, India Needs More Nuclear Tests: Pokhran II Coordinator,” The Times of India, August 27, 2009.
46 “Top Indian Scientists Say Nuclear Tests Were Successful,” Global Security Newswire, September 25, 2009.
47 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.
48 “Japan-India Atomic Trade Talks Stall over CTBT,” Global Security Newswire, October 26, 2010, http://gsn.nti.org/
gsn/nw_20101026_7486.php.
49 Kathy Gannon, “New Pakistani Government Gives First Official Foreign Policy Statement,” newswire, Associated
Press, November 8, 1999.
50 Shahid-ur-Rehman Khan, “Signing CTBT Can Destabilize Pakistan, Says Musharraf,” newswire, Kyodo News
International, Inc., August 17, 2000.
51 “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.
52 “Pak Says No to Signing NPT, CTBT Unilaterally,” Press Trust of India Limited, April 26, 2007.
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Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

national interest.”53 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.”54 As of December 2011, 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
threatened to ‘transfer’ or ‘demonstrate’ its nuclear weapons.”55 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,”56 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.57 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.”58 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.”59 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 the Six-Party Talks, see CRS Report R41259, North Korea:
U.S. Relations, Nuclear Diplomacy, and Internal Situation
, by Emma Chanlett-Avery.
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.60 According to other reports, South Korean
geologists placed the explosive yield at 550 tons of TNT equivalent (0.55 kilotons),61 the French

53 “Pakistan Would Consider Nuclear Test If India Tests,” Reuters, August 20, 2007, available at http://in.reuters.com/
article/topNews/idINIndia-29063920070820.
54 “Pakistan Rules Out Test Ban Treaty Endorsement,” Global Security Newswire, June 19, 2009.
55 “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.
56 “Korean Central News Agency North Korea February 10,” The Guardian, February 12, 2005.
57 David Sanger, “U.S. in Warning to North Korea on Nuclear Test,” New York Times, May 16, 2005, p. 1.
58 “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.
59 Democratic People’s Republic of Korea, Foreign Ministry Statement, Pyongyang Korean Central Broadcasting
Station, October 3, 2006.
60 “White House Casts Doubt on N. Korean Nuclear Arms,” Reuters newswire, October 10, 2006.
61 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.
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Atomic Energy Commission’s estimate was 0.50 kilotons,62 and Russian Minister of Defense
Sergei Ivanov placed the yield at 5 to 15 kilotons.63 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,64 and below the 4 kilotons that North Korea reportedly told China that
it expected.65 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.”66
Most U.S. observers cited in news reports believe that 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.67 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.68 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.69
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.70 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

62 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.
63 William Broad and Mark Mazzetti, “Blast May Be Only a Partial Success, Experts Say,” New York Times, October
10, 2006, p. 8.
64 James Sterngold, “U.S. Urges Sanctions to Restrain North Korea,” San Francisco Chronicle, October 10, 2006, p. 1.
65 Broad and Mazzetti, “Blast May Be Only a Partial Success, Experts Say.”
66 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.
67 Dafna Linzer and Thomas Ricks, “U.S. Waits for Firm Information on Nature and Success of Device,” Washington
Post,
October 11, 2006, p. 14.
68 Dafna Linzer, “Low Yield of Blast Surprises Analysts,” Washington Post, October 10, 2006, p. 12.
69 Personal communication, October 13, 2006.
70 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.
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seismic wave patterns that are diagnostic of an explosive source.71 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.72
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
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.73
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 one-fifth of a 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 Comprehensive Nuclear-
Test-Ban Treaty Organization Preparatory Commission, for example, states, “the CTBT
verification regime proved that it was capable of meeting the expectations set for it,”74 even
though the test was low yield, the IMS was 60% completed, and the noble gas system was 25%
completed.75 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.76 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.”77 The lack of certainty on whether the test was nuclear arises because

71 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.
72 Personal communication, October 10, 2006.
73 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.
74 “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.
75 Information provided by CTBTO PrepCom, personal communication, February 15, 2008.
76 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 Nikitin.
77 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,
(continued...)
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seismic signals, including those detected by 61 stations of the International Monitoring System
(described below),78 were consistent with a nuclear test, and seismic signals from the 2006 and
2009 events were very similar,79 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 Preparatory Commission 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
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.80
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 Medalia.
In response to the event, the U.N. Security Council adopted resolution 1874 on June 12, 2009.81
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 Nikitin and Mark E. Manyin.) Since shortly
after the second test, there have been conflicting, ambiguous, or speculative reports on whether
North Korea was preparing for another nuclear test, with some as recent as February and April

(...continued)
June 15, 2009, at http://www.dni.gov/press_releases/20090615_release.pdf .
78 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/.
79 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 .
80 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/.
81 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.
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2011.82 As of December 2011, that nation had not conducted another test and had not signed the
CTBT.
The CTBT: Negotiations, Provisions, Entry into
Force, CTBTO Budget

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 and funded by the United
Nations, yet is autonomous from the U.N. 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).83 That
treaty entered into force in 1970. It divided the world into nuclear “haves”—the United States,
Soviet Union, Britain, France, and China, the five84 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

82 “North Korea Digs Tunnels for Likely Nuclear Test—Report,” Reuters, February 19, 2011; and “N. Korea Ready for
Atomic Test Any Time,” Agence France Presse, April 19, 2011. See also “U.S. Visitor Saw No Sign of Resumed
North Korean Nuke Work,” Global Security Newswire, November 8, 2010, and “North Korea: Newspaper in South
Reports Activity at Nuclear Test Site,” New York Times, October 21, 2010.
83 For text of the treaty, see http://www.state.gov/t/isn/trty/16281.htm#treaty.
84 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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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
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.”85 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.”86 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.”87 Ihor Dolhov, Deputy
Foreign Minister for Foreign Affairs of Ukraine, said, “Ukraine continues to underscore the

85 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.
86 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.
87 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.
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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.”88 Ambassador
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.”89
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.”90 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.”91 Indonesia is one of the remaining
nine nations that must ratify the CTBT 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.”92 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.”93 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.94

88 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.
89 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.
90 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.
91 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.
92 “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.
93 “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.
94 “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.”95
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.”96 Views differ on whether the ban covers tests with the tiniest
nuclear yield; unless cooperative monitoring measures were used, the yield of such tests would be
below the threshold of detection. Opponents of the treaty argue that the treaty “fails to define
what it purports to prohibit,” that is, a “nuclear test,” and that Russia did not agree to ban even the
tiniest nuclear explosions (see “Stockpile Stewardship,” below).97 Supporters respond that the
negotiating record makes clear that Russia agreed that “experiments which do produce a nuclear
yield ... would be banned.”98
Organization (Article II): The treaty establishes a Comprehensive Nuclear-Test-Ban Treaty
Organization (CTBTO), composed of all member states, to implement the treaty.99 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
scope of the treaty and oversee the work of the other groups. An Executive Council with 51
member states shall, among other things, take action 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 for signals 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

95 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).
96 India, “Statement by Ms. Arundhati Ghose, ... January 25, 1996.”
97 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, p. 15.
98 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.
99 For further information on the CTBTO, see its website at http://www.ctbto.org.
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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
December 2011, of the 337 facilities, 29 are planned, 23 are under construction, 19 are
undergoing testing, and 266 have been certified, that is, they are completed and meet the technical
requirements of the Preparatory Commission.100 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.101 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, 2009.102 “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.”103 Critics would note that a
focus on progress implies less focus on possible difficulties. A similar conference was held June
8-10, 2011, in Vienna.104 Another ISS conference will be held in 2013.105 In September 2008, the
PrepCom conducted its large-scale Integrated Field Exercise 2008 in Kazakhstan to simulate a
complete on-site inspection.106 The PrepCom called the exercise a success.107 In November 2010,
the PrepCom held a simulated on-site inspection in Jordan to improve capability to detect
evidence of clandestine testing.108 109 On October 24, 2011, the PrepCom endorsed a budget of

100 The Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission provides updated information on these
facilities at http://www.ctbto.org/map/#ims.
101 Information provided by Annika Thunborg, Chief, Public Information, Comprehensive Nuclear-Test-Ban Treaty
Preparatory Commission, personal communication, November 26, 2007.
102 For links to publications of the conference, see “ISS09, International Scientific Studies,” http://www.ctbto.org/
specials/the-international-scientific-studies-project-iss/.
103 ISS09—International Scientific Studies, “International Scientific Studies Conference, Vienna, 10-12 June 2009,” p.
1.
104 Documents from, and about, this conference are available on its website, Preparatory Commission for the
Comprehensive Nuclear-Test-Ban Treaty, “Comprehensive Nuclear-Test-Ban Treaty: Science and Technology 2011,”
http://www.ctbto.org/specials/ctbt-science-and-technology-20118-10-june-2011-vienna-austria/.
105 Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, “Verifying the CTBT—An
Unprecedented Technical Undertaking,” June 27, 2011, http://www.ctbto.org/press-centre/highlights/2011/verifying-
the-ctbt-an-unprecedented-technical-undertaking/7/.
106 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/.
107 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/.
108 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/.
109 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.
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$10.3 million for an integrated field exercise in 2014. This exercise is intended to improve the
organization’s on-site inspection capabilities.110
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. Since the treaty had not entered into force as of December 2011, 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. 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.
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 December 2011,
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. An 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 most recent 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.”111
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

110 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/.
111 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.
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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 Comprehensive
Nuclear-Test-Ban Treaty Organization (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.”112 The
PrepCom held 37 meetings from November 1996 through October 2011; as of December 2011,
the next is scheduled for June 14-15, 2012. Nine meetings of working groups and advisory groups
are scheduled for 2012. The PrepCom also holds training sessions, workshops, etc.113
The United Nations has conducted entry-into-force conferences under Article XIV every second year
beginning in 1999. The CTBTO PrepCom serves as the secretariat of these conferences. 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.114 The
most recent conference was held September 23, 2011, at U.N. Headquarters in New York. The final
declaration 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.115
There have been other calls for entry into force. In September 2002, a statement by 18 foreign
ministers, including those of Britain, France, and Russia, called for early entry into force. On
November 22, 2002, the U.N. General Assembly adopted resolution 57/100 (164 for, 1 against
(U.S.A.), 5 abstentions) urging states to maintain their nuclear test moratoria and urging states that

112 “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.
113Preparatory Commission for the Comprehensive Nuclear-Test Ban Treaty Organization, “Meeting Schedule and
Calendar of Events,” http://www.ctbto.org/the-organization/meeting-schedule-and-calendar-of-events/.
114 “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.
115 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.
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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. In a message to the 2003 conference, 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.”116 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.”117 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.118 A report by 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.”119 In
September 2006, to mark the tenth 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.”120
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.”121 In response, a few
weeks later, Mikhail Gorbachev called on nuclear weapon states to ratify the CTBT, among other
actions.122 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.123 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

116 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.
117 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.
118 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.
119 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.
120 “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.
121 George Shultz, William Perry, Henry Kissinger, and Sam Nunn, “A World Free of Nuclear Weapons,” Wall Street
Journal,
January 4, 2007, p. 15.
122 Mikhail Gorbachev, “The Nuclear Threat,” Wall Street Journal, January 31, 2007, p. 13.
123 Harold Brown and John Deutch, “The Nuclear Disarmament Fantasy,” Wall Street Journal, November 19, 2007, p.
19.
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urgently support even prior to [CTBT] ratification.”124 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.”125 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.”126
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.”127 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.”128 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.129 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.130 On December 2, 2008, the U.N. General

124 George Shultz, William Perry, Henry Kissinger, and Sam Nunn, “Toward a Nuclear-Free World,” Wall Street
Journal,
January 16, 2008, p. 13.
125 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.
126 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.
127 “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.
128 “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.
129 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.
130 “Registration as UN Document of a Joint Statement of 4th Comprehensive Nuclear-Test-Ban Treaty (CTBT)
Ministerial Meeting,” States News Service, January 8, 2009.
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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).131
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.”132 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.133 A Council on Foreign Relations task force, in a 2009 report,
“believes that the benefits outweigh the costs and that the CTBT is in U.S. national security
interests.”134 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.”135
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.136
Budget of the CTBTO Preparatory Commission
The PrepCom’s assessed budget is presented in dollars plus euros; its 2011 budget is $54.5
million plus €56.5 million.137 (The PrepCom uses the calendar year as its fiscal year.) The U.S.
assessment is 22.35% of the total. 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. These funds are in the International Affairs

131 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.
132 “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.
133 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/
America's_Strategic_Posture_Auth_Ed.pdf.
134 Council on Foreign Relations. Independent Task Force Report No. 62. U.S. Nuclear Weapons Policy, 2009, p. 89.
135 “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.
136 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.
137 Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, “CTBTO Member States’ Payment as at 30-
Sep-2011,” p. 4, http://www.ctbto.org/fileadmin/user_upload/treasury/30Sept2011_Member_States__payments.pdf.
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budget under Nonproliferation, Antiterrorism, Demining, and Related Programs. 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.”138 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 regime will be
fully operational when the CTBT enters into force.”139 In 2010, the United States paid off an
outstanding prior years balance of $22.323 million.140 The assessed contribution for the United
States for 2011 is $12.174 million plus €12.617 million. As of November 30, 2011, the U.S.
outstanding balance was $0 plus €6.9 million, and the total outstanding balance for all member
states was $9.6 million plus €10.1 million.141
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.”142 The Administration’s FY2012 request for the PrepCom is
in the same two parts, $33.0 million for the IMS and $7.5 million for specific projects.143 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.”144
Stockpile Stewardship
P5 states want to maintain their nuclear warheads under a CTBT and assert that they need
computers and scientific facilities to do so. They also want to retain the ability to resume testing if
other nations leave a CTBT, or if maintaining high confidence in key weapons requires testing.
Nonnuclear nations fear that the P5 will continue to design new warheads under a CTBT, with

138 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.
139 Clinton, “Remarks at CTBT Article XIV Conference,” p. 4.
140 Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, “CTBTO Member States’ Payment as at 05-
Nov-2010,” p. 4.
141 Comprehensive Nuclear-Test-Ban Treaty Preparatory Commission, “CTBTO Member States’ Payment as at 30-
Nov-2011,” p. 4, http://www.ctbto.org/fileadmin/user_upload/treasury/
30Nov2011_Member_States__payments_01.pdf.
142 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.
143 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.
144 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.
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computation and nonnuclear experiments replacing testing. Maintaining nuclear weapons,
especially without testing, is termed “stockpile stewardship.”
Congress established the National Nuclear Security Administration (NNSA) in Title XXXII of
P.L. 106-65 (S. 1059), 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, the main elements of which are Directed Stockpile Work,
activities directly supporting weapons in the stockpile; Campaigns, technical efforts to develop
and maintain capabilities to certify the stockpile for the long term; and Readiness in Technical
Base and Facilities, mainly weapons complex infrastructure and operations. 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, and FY2011, $6.896 billion.
For FY2012 Weapons Activities funding, the request is $7,629.7 million.145 The national defense
authorization bill, H.R. 1540, as passed by the House (322-96, May 26, 2011), provided the
amount requested. The FY2012 energy and water development bill, H.R. 2354, as passed by the
House (219-196, July 15), provided $7,132.0 million, of which $40.3 million is to come from
unobligated balances from prior year appropriations. The Senate Armed Services Committee, in
S. 1253, recommended authorizing $7,628.7 million, and the Senate Appropriations Committee,
in H.R. 2354, recommended appropriating $7,190.0 million. (For further information on the
Weapons Activities budget, see CRS Report R41908, Energy and Water Development: FY2012
Appropriations
, coordinated by Carl E. Behrens.)
Stewardship is a contentious issue. It 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
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.146
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”;

145 For details of the FY2012 Weapons Activities request, see U.S. Department of Energy. Office of Chief Financial
Officer., FY 2012 Congressional Budget Request: Volume 1, National Nuclear Security Administration, DOE/CF-0057,
February 2011, pp. 41-317, http://www.cfo.doe.gov/budget/12budget/Content/Volume1.pdf.
146 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.
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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.”147 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.) 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 Medalia.
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.”148
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, having already certified the stockpile 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. As of August 2011, DOD and DOE had completed
15 annual assessments.
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.”149
A Council on Foreign Relations task force found, “concerns about ensuring the highest caliber
workforce at the weapons laboratories.”150 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

147 U.S. White House. Office of the Press Secretary. “Fact Sheet: Comprehensive Test Ban Treaty Safeguards,” August
11, 1995, 1 p.
148 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.
149 Congressional Commission on the Strategic Posture of the United States, America’s Strategic Posture, p. 62.
150 Council on Foreign Relations. Independent Task Force Report No. 62, U.S. Nuclear Weapons Policy, p. 76.
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is threatened by lack of program stability, perceived lack of mission importance, and degradation
of the work environment.”151 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
could be extended for decades, with no anticipated loss in confidence, by using approaches
similar to those employed in LEPs to date.”152 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.”153
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.154
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.”155 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.156 In May, the President submitted New START to the Senate and provided a

151 “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.
152 Ibid., p. 2. Original text was bolded.
153 George Shultz, William Perry, Henry Kissinger, and Sam Nunn, “How to Protect Our Nuclear Deterrent,” Wall
Street Journal
, January 20, 2010, p. 17.
154The Honorable Mitch McConnell et al., letter to The Honorable Barack Obama, President, December 15, 2009.
155 Vice President Joe Biden, “The President’s Nuclear Vision,” Wall Street Journal, January 29, 2010, p. 15.
156 U.S. Department of Defense, Nuclear Posture Review, pp. 37-43.
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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.”157 The directors of the three nuclear weapons laboratories commented on the Nuclear
Posture Review as follows:
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.”158
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.”159 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.”160 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.”161
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

157 U.S. White House. “The New START Treaty—Maintaining a Strong Nuclear Deterrent,” May 13, 2010,
http://www.america.gov/st/texttrans-english/2010/May/20100514114003xjsnommis0.6300318.html.
158 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/.
159 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.
160 “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.
161 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.
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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.”162 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
than at the FY2010 rate of $6,384.4 million. In November 2010, the Administration reportedly
offered additional Weapons Activities funds. “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.”163 The
Administration presented this funding plan in a report of November 2010. 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.164
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).”165
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.166 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

162 Walter Pincus, “Similar Treaty but a Different Republican Reaction,” Washington Post, August 10, 2010, p. 15.
163 Mary Beth Sheridan and Walter Pincus, “Sources: $4 Billion Bid to Save START,” Washington Post, November 13,
2010, p. 3.
164 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.
165 “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.
166 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.)
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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.”167
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.
The programmatic and political consequences of a reduction in Weapons Activities funding on the
scale implied in action on the appropriations bills are unclear.
Subcritical experiments (SCEs): As part of the stockpile stewardship program, NNSA is
conducting SCEs. CRS offers the following definition based on documents and on discussions
with DOE and laboratory staff: “Subcritical experiments at Nevada National Security Site
(NNSS, formerly Nevada Test Site, NTS) involve chemical high explosives and fissile materials
in configurations and quantities such that no self-sustaining nuclear fission chain reaction can
result. In these experiments, the chemical high explosives are used to generate high pressures that
are applied to the fissile materials.” The only fissile material that has been used in SCEs is
plutonium. All SCEs but one have been conducted in the U1a tunnel complex, about 1,000 feet
underground at NNSS. The 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.168 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.”169 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.170 (For further
information on subcritical experiments and test readiness, see CRS Report RL32130, Nuclear
Weapon Initiatives: Low-Yield R&D, Advanced Concepts, Earth Penetrators, Test Readiness
, by
Jonathan Medalia.)
The 26 SCEs held so far are: 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

167 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
168 “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.
169 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.
170 U.S. Department of Energy. Office of Management, Budget and Evaluation/CFO. FY 2006 Congressional Budget
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.
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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. In July 2011, NNSA stated that no further
SCEs were scheduled for FY2011.
Other experiments: 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.” Twelve such experiments were conducted between
February and May 2007; none had been conducted since then as of August 2011.171 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.172 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.
NNSA laboratories and NNSS also conduct other types of experiments in support of stockpile
stewardship. An NNSA report of June 2011 describes the following experimental facilities: the
High Explosive Application Facility at Livermore, which studies properties of chemical
explosives; the Large Bore Powder Gun at NNSS, which is used to investigate properties of
plutonium and other metals; the Los Alamos Neutron Science Center, which generates neutrons to
study material properties and generates protons for radiography; the Big Explosives Experimental
Facility at NNSS, which studies “materials as they are merged together by high-explosives
detonations”; TA-55 at Los Alamos, which has facilities to investigate properties of plutonium
and other metals; 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 materials, radiation, plasma, and other aspects of nuclear explosions at
extreme temperatures and pressures; the Z-Machine at Sandia, for investigating properties of
material, plasma, and radiation; and Omega, at University of Rochester, also for studying
properties of material, plasma, and radiation at high temperatures and pressures.173
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.”174 In January 2002 the Nuclear Posture Review briefing called

171 Information provided by National Nuclear Security Administration, Nevada Site Office, personal communication,
August 3, 2011.
172 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.
173 U.S. Department of Energy. National Nuclear Security Administration. “Summary of Experiments Conducted in
Support of Stockpile Stewardship,” May 2011 (final for first through third quarters of FY2011), 3 p.,
http://nnsa.energy.gov/sites/default/files/nnsa/inlinefiles/SSP_quarterly_August2011.pdf.
174 U.S. Department of Energy. Office of Inspector General. Office of Audit Services. National Nuclear Security
(continued...)
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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.”175 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 FY2005.176
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.”177 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.”178 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.”179 The FY2005 Consolidated Appropriations Act reduced this campaign
by $7.5 million.
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.”180 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

(...continued)
Administration’s Test Readiness Program, Audit Report, September 2002, p. 1.
175 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.
176 U.S. Department of Energy. National Nuclear Security Administration. Nuclear Test Readiness. Report to Congress,
April 2003, p. 5-8.
177 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.
178 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.
179 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.
180 Department of Energy, FY 2006 Congressional Budget Request, Volume 1, p. 93.
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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.181 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.”182 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.”183 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 FY2005.184 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.”185 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.”186 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:
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

181 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.
182 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.
183 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.
184 Department of Energy, FY 2007 Congressional Budget Request. Volume 1, National Nuclear Security
Administration, p. 97.
185 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.
186 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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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.187
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.188 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.”189 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.”190 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.191 According to NNSA,
“The responsibility for the maintenance of infrastructure and physical assets at the NTS
transferred to the RTBF program in FY 2010.”192
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.”193 A DOE report of May 2011 provides further details.194

187 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.
188 Department of Energy, FY2009 Congressional Budget Request, vol. 1, p. 133.
189 Ibid., p. 135.
190 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.
191 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.
192 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.
193 Information provided to CRS by National Nuclear Security Administration, e-mail, November 29, 2010.
194 U.S. Department of Energy. “Nuclear Test Readiness.” Report to Congress, May 2011.
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Table 1. 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
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 August 2011, DOD and DOE had completed 15 annual assessments of the stockpile
and found it to be safe, secure, and reliable.195 The treaty’s 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
because it reduces the incentive for friends and foes alike to build their own nuclear weapons, that

195 Information provided by Los Alamos National Laboratory, personal communication, August 2, 2011.
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nonproliferation and disarmament are unrelated, and that the international community gives this
nation little credit for its many nonproliferation and disarmament actions.
Chronology
12/06/11—Indonesia became the 156th 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.
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.”
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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.”
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.
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.
06/08/09—Foreign Minister Hassan Wirajuda of Indonesia said that his nation would
“immediately” ratify the CTBT once the United States did so.
05/25/09—North Korea announced that it had conducted a nuclear test, its second.
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.”
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
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.”
11/21/08—Lebanon became the 148th nation to ratify the CTBT.
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.
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.
08/19/08—Iraq became the 179th nation to sign the CTBT.
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06/26/08—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 30th meeting.
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.”
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.
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.
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.
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.
12/05/07—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.
11/19/07—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.
11/14/07—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 29th meeting.
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.
09/00/07—The United Nations held the fifth conference on facilitating CTBT entry into force on
September 17 and 18 in Vienna, Austria.
06/22/07—The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty
Organization concluded its 28th meeting.
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.
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03/29/07—The Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission
certified the 200th and 201st International Monitoring System stations.
01/31/07—Mikhail Gorbachev called on nuclear weapon states to ratify the CTBT.
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.”
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).
American Association for the Advancement of Science, American Physical Society, and Center
for Strategic and International Studies, Joint Working Group, “Nuclear Weapons in 21st
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“Joint Ministerial Statement on the CTBT,” New York, September 23, 2010, 3 p.,
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Walter, Katie, “Sleuthing Seismic Signals,” Science & Technology Review, March 2009, pp. 4-12.
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Appendix. Chronology, 1992-2006
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 U.N.
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 U.N., 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.”
2/10/05—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.
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.
6/00/06—The 26th meeting of the Preparatory Commission for the Comprehensive Nuclear Test
Ban Treaty Organization was held June 20-23.
8/30/06—The United States conducted its 23rd subcritical experiment, “Unicorn,” at the Nevada
Test Site.
9/20/06—Fifty-nine foreign ministers called on states that have not done so to ratify the treaty.
9/28/06—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.

Author Contact Information

Jonathan Medalia

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


Congressional Research Service
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