Order Code RL32929
CRS Report for Congress
Received through the CRS Web
Nuclear Weapons: The Reliable
Replacement Warhead Program
May 24, 2005
Jonathan Medalia
Specialist in National Defense
Foreign Affairs, Defense, and Trade Division
Congressional Research Service ˜ The Library of Congress

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Nuclear Weapons: The Reliable
Replacement Warhead Program
Summary
Most current U.S. nuclear warheads were built in the 1980s, and are being
retained longer than was planned. Yet warheads deteriorate with age, and must be
maintained. The current approach monitors them for signs of aging. When problems
are found, a Life Extension Program (LEP) rebuilds components. While some can
be made to new specifications, a nuclear test moratorium bars that approach for
critical components that would require a nuclear test. Instead, LEP rebuilds them
as closely as possible to original specifications. Using this approach, the Secretaries
of Defense and Energy have certified stockpile safety and reliability for the past nine
years without nuclear testing.
In the FY2005 Consolidated Appropriations Act, Congress initiated the Reliable
Replacement Warhead (RRW) program by providing $9 million for it. The program
will study developing replacement components for existing weapons, trading off
features important in the Cold War, such as high yield and low weight, to gain
features more valuable now, such as lower cost, elimination of some hazardous
materials, greater ease of manufacture, greater ease of certification without nuclear
testing, and increased long-term confidence in the stockpile. It would modify
components to make these improvements; in contrast, LEP makes changes mainly
to maintain existing weapons. Representative David Hobson, RRW’s prime sponsor,
views it as part of a comprehensive plan for the U.S. nuclear weapons enterprise that
would also modernize the nuclear weapons complex, avoid new weapons and nuclear
testing, and permit a reduction in non-deployed weapons. The FY2006 request is
$9.4 million.
RRW supporters assert LEP will become harder to sustain for the long term as
small changes accumulate, making it harder to certify warhead reliability and safety
and perhaps requiring nuclear testing. Supporters believe RRW will enable design
of replacement components for existing warheads that will be easier to manufacture
and certify without nuclear testing, and will permit the military to eliminate many
non-deployed warheads it maintains, at high cost, to hedge against potential warhead
or geopolitical problems. Skeptics believe LEP and related programs can maintain
the stockpile indefinitely. They worry that RRW’s changes may reduce confidence
and make a return to testing more likely. They question cost savings; even if RRW
could lower operations and maintenance cost, its investment cost would be high.
They are concerned that RRW could be used to build new weapons that would
require testing. They note that there are no military requirements for new weapons.
At issue for Congress is which approach — LEP, RRW, some combination, or
something else — will best maintain the nuclear stockpile indefinitely. RRW bears
on other issues of interest to Congress, including new weapons development, nuclear
testing, restructuring of the nuclear weapons complex, costs of nuclear programs, and
nuclear nonproliferation. This report will be updated as events warrant.

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Contents
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Issue Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Congress, Nuclear Policy, and RRW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
The Need to Maintain Nuclear Warheads for the Long Term . . . . . . . . . . . . 5
The Solution So Far: The Life Extension Program . . . . . . . . . . . . . . . . . . . . 8
Is LEP Satisfactory for the Long Term? . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
RRW and the Transformation of Nuclear Warheads . . . . . . . . . . . . . . . . . . 11
RRW and the Transformation of the Nuclear Weapons Enterprise . . . . . . . 14
Skeptics’ Views of RRW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Issues for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Are the Surveillance Program and LEP Sufficient to
Maintain the Stockpile? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Is RRW Needed in Order to Provide New Military Capabilities? . . . . 20
Might RRW Permit a Reduction in Warhead Numbers? . . . . . . . . . . . 21
Will RRW Save Money? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
How Might RRW Affect the Nuclear Weapons Complex? . . . . . . . . . 23
Might RRW Undermine U.S. Nonproliferation Efforts? . . . . . . . . . . . 24
Might LEP or RRW Lead to Nuclear Testing? . . . . . . . . . . . . . . . . . . 25
Might RRW Enable an Increase In Inherent Warhead Security? . . . . . 26
Might RRW Enable an Increase In Warhead Safety? . . . . . . . . . . . . . 27
Might RRW Reduce Adverse Consequences of Aging? . . . . . . . . . . . 28
Might RRW Enable Reduced Use of Hazardous Materials? . . . . . . . . 28
Policy Options for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Appendix: Nuclear Weapons and the Nuclear Weapons Complex . . . . . . . . . . 31

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Nuclear Weapons: The Reliable
Replacement Warhead Program
Background
Issue Definition
Nuclear warhead components deteriorate with age. Without periodic
maintenance, warheads might not detonate as intended or might fail to meet safety,
security, and other requirements. Congress is poised to review alternative methods
to maintain the nuclear stockpile for the long term. The current method, the Life
Extension Program (LEP), replaces deteriorated components. Some, such as the
outer casing or certain electronics, can be modified, but LEP replaces those in the
nuclear explosive package (see Appendix) with newly-produced components
manufactured using original designs and, insofar as possible, original materials.
Congress created a program, Reliable Replacement Warhead (RRW), in the FY2005
Consolidated Appropriations Act to study a new approach to maintaining warheads
over the long term. RRW would redesign components to be easier to manufacture,
among other characteristics. The Nuclear Weapons Council, a joint Department of
Defense (DOD) and Department of Energy (DOE) organization that oversees nuclear
weapons activities, views RRW as the foundation of a plan to transform the entire
nuclear weapons enterprise to one with a smaller yet more capable production base
and far fewer spare warheads. The issue for Congress is how best to maintain the
nuclear stockpile for the long term. A decision on this issue is important because,
through it, Congress may affect the characteristics of U.S. nuclear forces; their ability
to carry out their assigned missions; perceptions of U.S. nuclear nonproliferation
policy; the capabilities and modernization of the nuclear weapons complex; and the
nuclear weapons budget.
Many find RRW to be confusing because it is a new program and descriptions
of it have changed. To provide a clearer understanding of what RRW seeks to
achieve, this report describes the current LEP and difficulties ascribed to it by its
critics; shows how post-Cold War changes in constraints may open opportunities to
improve long-term warhead maintenance and reach other goals; presents views of
LEP supporters; and presents issues and options for Congress. A brief appendix
describes nuclear weapon design and operation and the nuclear weapons complex.
This report does not consider the larger questions of retaining U.S. nuclear weapons
or the strategic uses and values of such weapons.
A note on terminology: RRW is in early stages of a study. It has not produced
any hardware. This report refers to “RRW components” and “RRW warheads” as
shorthand for components that might be developed under RRW, should that program
proceed successfully, and warheads incorporating RRW components.

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Congress, Nuclear Policy, and RRW
Congress has been involved with nuclear weapons issues since the Manhattan
Project of World War II,1 addressing issues ranging from strategy and doctrine to
force structure and operations.
In the Floyd D. Spence National Defense Authorization Act for FY2001, P.L.
106-398, section 1041, Congress directed the Administration to undertake a Nuclear
Posture Review (NPR). This review, which the Administration presented to
Congress in January 2002, set forth a new view of the role of nuclear weapons in
U.S. defense policy.2 It recognized that the strategic relationship with Russia had
changed dramatically since the end of the Cold War, and that new and poorly-defined
threats could emerge. Accordingly, it called for a change in the nuclear posture from
one based on countering a specific threat from the Soviet Union to one that would
have a set of capabilities to counter a range of potential future threats, such as the
increasing use by potential adversaries of hardened and deeply buried facilities.
These capabilities were unified in a “New Triad.” Beginning in the early 1960s, the
United States had a “triad” of nuclear forces — bombers, land-based intercontinental
ballistic missiles, and submarine-launched ballistic missiles. The New Triad
included offensive strike capabilities, which combined the “old” nuclear triad with
precision strike conventional forces; missile defenses; and an industrial
infrastructure, nuclear and nonnuclear, responsive to DOD needs.
The Administration has indicated that it welcomes a dialog with Congress on
broad nuclear policy.3 At the same time, Congress has tended to focus on several
1 Richard Hewlett and Oscar Anderson, Jr., A History of the United States Atomic Energy
Commission: Volume I, The New World, 1939/1946, University Park, PA, Pennsylvania
State University Press, 1962, p. 289-290, discusses the handling of appropriations for the
project.
2 The NPR was prepared in classified form; DOD provided unclassified briefing slides and
an unclassified briefing on it. For the briefing, see U.S. Department of Defense. News
Transcript: “Special Briefing on the Nuclear Posture Review,” J.D. Crouch, Assistant
Secretary of Defense for International Security Policy, presenter, January 9, 2002, at
[http://www.defenselink.mil/transcripts/2002/t01092002_t0109npr.html]. For the slides,
see U.S. Department of Defense. “Findings of the Nuclear Posture Review,” January 9,
2002, at [http://www.defenselink.mil/news/Jan2002/020109-D-6570C-001.pdf]. See also
U.S. Congress. Congressional Research Service. NuclearWeapons: Changes in Policy and
Force Structure. CRS Report RL31623, by Amy Woolf.
3 In a prepared statement to Congress, General James Cartwright, USMC, said: “And
finally, as an element of our role as steward of the nation’s strategic nuclear capabilities, we
need you to ... [c]onsider a new national dialogue on nuclear policy.” “Statement of General
James E. Cartwright, USMC, Commander, United States Strategic Command, before the
Senate Armed Services Committee, Strategic Forces Subcommittee, on Strategic Forces and
Nuclear Weapons Issues in Review of the Defense Authorization Request for Fiscal Year
2006,” April 4, 2005, p. 15-16. NNSA Administrator Linton Brooks, in a prepared
statement to Congress, said, “The Administration is eager to work with the Congress to
forge a broad consensus on an approach to stockpile and infrastructure transformation.”
“Statement of Ambassador Linton F. Brooks, Administrator, National Nuclear Security
(continued...)

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specific issues. In the FY2005 budget cycle, for example, it focused on the Robust
Nuclear Earth Penetrator (RNEP), often called the “bunker buster,” a study to
determine if an existing nuclear bomb could be modified to penetrate the ground
before exploding to increase its effectiveness against buried targets. Congress also
considered the Advanced Concepts Initiative (ACI), a program to study nuclear
weapon-related technologies.4
In debate on FY2005 defense authorization bills, the House and Senate defeated
amendments to terminate RNEP and ACI, leaving the full amount requested, $27.6
million for RNEP and $9.0 million for ACI, in the FY2005 National Defense
Authorization Act (P.L. 108-375). In contrast, the House Appropriations
Committee’s energy and water bill eliminated funding for both programs at the
urging of Representative David Hobson, Chairman of the Energy and Water
Development Appropriations Subcommittee. That subcommittee has jurisdiction
over the National Nuclear Security Administration (NNSA), which operates the
nuclear weapons program. This position was not challenged on the House floor. The
Senate Appropriations Committee did not report an energy and water bill for
FY2005. Conferees on the FY2005 Consolidated Appropriations Act (P.L. 108-447),
which included energy and water provisions, followed the House position on RNEP
and ACI and, at the urging of Representative Hobson, transferred all ACI funds to
RRW, a new program created by the bill. The entire description of RRW in the
conference report was a “program to improve the reliability, longevity, and
certifiability of existing weapons and their components.”5
Consistent with congressional action, NNSA included $9.4 million for RRW in
its FY2006 budget request.6 Like the description in the conference report, the
3 (...continued)
Administration, U.S. Department of Energy, before the Senate Armed Services Committee,
Subcommittee on Strategic Forces,” April 4, 2005, p. 7. Hereinafter “Brooks statement to
Senate Armed Services Committee, April 4, 2005.”
4 For history and technology of these programs, see CRS Report RL32130, Nuclear Weapon
Initiatives: Low-Yield R&D, Advanced Concepts, Earth Penetrators, Test Readiness., by
Jonathan Medalia. For the current situation with RNEP, see CRS Report RL32347, Robust
Nuclear Earth Penetrator Budget Request and Plan, FY2005-FY2010, by Jonathan Medalia.
5 U.S. Congress. Committee of Conference .Making Appropriations for Foreign Operations,
Export Financing, and Related Programs for the Fiscal Year Ending September 30, 2005,
and For Other Purposes, conference report to accompany H.R. 4818, H.Rept. 108-792, 108th
Congress, 2nd Session, 2004, reprinted in U.S. Congress. Congressional Record, November
19, 2004, Book II: H10556.
6 To clarify a point of confusion, the FY2006 NNSA budget request shows an aggregate
request for FY2006-FY2010 of $97.1 million. NNSA had insufficient time between
December 8, 2004, when P.L. 108-375 was signed, and February 7, 2004, when the budget
request was sent to Congress, to prepare a detailed program and cost estimate. Further,
Congress had directed that NNSA transfer ACI funds to RRW for FY2005. Accordingly,
NNSA relabeled the ACI budget line as RRW. Thus the $97.1 million should be viewed as
a placeholder, not an estimate. Note: budget figures are from U.S., Department of Energy,
Office of Management, Budget, and Evaluation/CFO, FY2006 Congressional Budget
(continued...)

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request takes a narrow view of RRW, stating that that program “is to demonstrate the
feasibility of developing reliable replacement components that are producible and
certifiable for the existing stockpile. The initial focus will be to provide cost and
schedule efficient replacement pits [see Appendix] that can be certified without
Underground Tests.”7
Based on such statements, and on discussions with adherents of various points
of view, it appears that RRW can be described as follows:
RRW is a new congressionally-mandated program. Under it, the National
Nuclear Security Administration (NNSA) will conduct a two-year study
beginning in FY2005 to determine if a new philosophy for refurbishing nuclear
warheads to reflect current constraints and opportunities can lead to a process for
manufacturing warheads and certifying their performance. It appears that this
process has as its direct goal the manufacture of new-design replacement
warhead components using best modern manufacturing practices to give future
nuclear weapon designers and manufacturers increased confidence, without
nuclear testing, in their ability to maintain warheads so that they will perform as
intended over the long term. Other goals include increased ease of manufacture
and certification, increased responsiveness to possible future military
requirements, reduced life cycle cost, reduced likelihood of nuclear testing,
increased weapon safety and security, and increased responsiveness to
environmental, safety, and health concerns
To achieve these goals, RRW would make several key tradeoffs, sacrificing
(assuming Department of Defense approval) warhead characteristics important
during the Cold War but less so now, such as weight, size, yield, and efficiency.
The main difference between RRW and the current approach to stockpile
maintenance, the Life Extension Program (LEP), is one of an underlying
philosophy. Under RRW, NNSA would make changes to weapon components,
including those in the nuclear explosive package in an effort to attain the
foregoing goals. Under LEP, NNSA makes changes chiefly to maintain
weapons, and in particular minimizes changes to the nuclear explosive package.
Most of the changes under RRW probably could be made under LEP. However,
they probably would not be because LEP strives to hold changes to a minimum.
Supporters anticipate that RRW offers a path to two larger goals: replacing
a large nuclear weapons stockpile with fewer but more reliable weapons, and
restructuring the nuclear weapons complex into one that is smaller, safer, more
efficient, more responsive, and less costly. Skeptics question whether some of
the tradeoffs and goals are feasible, necessary, or worth potential costs and risks.
6 (...continued)
Request. Volume I, National Nuclear Security Administration. DOE/ME-0046, February
2005, p. 68. NNSA provided information on the change from ACI to RRW.
7 Department of Energy, FY2006 Congressional Budget Request, Volume I, p. 82.

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The Need to Maintain Nuclear Warheads for the Long Term
Nuclear warheads must be maintained because they contain thousands of parts
that deteriorate at different rates. Some parts, such as tritium reservoirs and neutron
generators,8 and materials, such as tritium, have well-known life limits, while the
service life of other parts may be unknown or revealed only by multiple inspections
of a warhead type over time. A 1983 report arguing that maintenance requires
nuclear testing, stated:
Certain chemically reactive materials are inherently required in nuclear weapons,
such as uranium or plutonium, high explosives, and plastics. The fissile
materials, both plutonium and uranium, are subject to corrosion. Plastic-bonded
high explosives and other plastics tend to decompose over extended periods of
time. ... portions of materials can dissociate into simpler substances. Vapors
given off by one material can migrate to another region of the weapon and react
chemically there. ... Materials in the warhead electrical systems ... can produce
effluents that can migrate to regions in the nuclear explosive portion of the
weapon. ... The characteristics of high explosives can change with time. ... Vital
electrical components can change in character ...9
A 1987 report, written to rebut the contention of the foregoing report that
nuclear testing is needed to maintain nuclear weapons, nonetheless agreed that aging
affects weapon components:
It should also be noted that nuclear weapons engineering has benefitted
from a quarter century of experience in dealing with corrosion, deterioration, and
creep since the time that the W45, W47, and W52 [warheads] entered the
stockpile in the early sixties (just after the test moratorium of 1958-1961). ...
Most of the reliability problems in the past have resulted from either an
incomplete testing program during the development phase of a weapon or the
aging and deterioration of weapon components during deployment.10
Some feel that deterioration, while a potential problem, has been overstated. A
scientific panel writing in 1999 stated,
there is no such thing as a “design life.” The designers were not asked or
permitted to design a nuclear weapon that would go bad after 20 years. They did
their best on a combination of performance and endurance, and after experience
with the weapon in storage there is certainly no reason to expect all of the
8 U.S. General Accounting Office. Nuclear Weapons: Capabilities of DOE’s Limited Life
Component Program to Meet Operational Needs, Letter Report, GAO/RCED-97-52, March
5, 1997, available at [http://www.globalsecurity.org/wmd/library/report/gao/rced97052.htm].
9 “Some Little-Publicized Difficulties with a Nuclear Freeze,” Prepared by Dr. J.W.
Rosengren, R&D Associates, under Contract to the Office of International Security Affairs,
U.S. Department of Energy, October 1983, p. 5-6; reprinted in U.S. Congress. Senate.
Committee on Foreign Relations. Nuclear Testing Issues. 99th Congress, 2nd Session, Senate
Hearing 99-937, 1986, p. 167-168.
10 Ray Kidder, Stockpile Reliability and Nuclear Test Bans: Response to J.W. Rosengren’s
Defense of His 1983 Report, Report UCID-20990, Lawrence Livermore National
Laboratory, February 1987, p. 4-5.

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CRS-6
nuclear weapons of a given type to become unusable after 20 or 25 years. In fact,
one of the main goals of SBSS [Science-Based Stockpile Stewardship, an earlier
term for the Stockpile Stewardship Program, discussed below] is to predict the
life of the components so that remanufacture may be scheduled, and results to
date indicate a margin of surety extending for decades. ... Until now, clear
evidence of warhead deterioration has not been seen in the enduring stockpile,
but the plans for remanufacture still assume that deterioration is inevitable on the
timescale of the old, arbitrarily defined “design lives.” 11
The deterioration noted above pertained to warheads designed in the 1950s and
early 1960s and no longer deployed; newer warheads correct some of these problems.
As knowledge of warhead performance, materials, and deterioration increases, the
labs are able to correct some problems and forestall others. Still other aging
problems have turned out to occur at a slower pace than was feared. In particular, it
was long recognized that plutonium would deteriorate as it aged, but it was not
known how long it would take for its deterioration to impair warhead performance.
Now, studies are underway to find out, and the current best estimate is that it would
take at least 45 to 60 years.
Any consequences of deterioration problems that arose during the Cold War
were limited in their duration because warheads had little time to age. The United
States introduced generation after generation of new nuclear “delivery vehicles” —
bombers, missile submarines, and land-based missiles — each of which would
typically carry a new-design warhead tailored to its characteristics and mission. A
warhead for a new missile, for example, might have to withstand a higher
acceleration, have a higher explosive yield, and be constrained to a specific volume.
New warheads were usually introduced long before the warheads they replaced
reached the end of their service lives. Two trends concerning deterioration have
emerged since the end of the Cold War. Nuclear warheads have much more time to
age, as warheads expected to remain in the stockpile for at most 20 years are being
kept there indefinitely. At the same time, Stockpile Stewardship and other tools
described below have greatly increased NNSA’s understanding of warhead
deterioration and how to deal with or prevent it. Also, by maintaining the current set
of warhead designs for many years, design and production errors have been subjected
to systematic identification and elimination.
Nuclear warheads are difficult to maintain. Yet an inability to maintain
warheads could erode the confidence of the United States, its friends and allies, and
its adversaries in the effectiveness of U.S. nuclear forces.
Nuclear warheads must be maintained so that the United States, its friends and
allies, and its adversaries will be confident about the effectiveness of U.S. nuclear
forces. Yet warheads are hard to maintain not only because of deterioration, but also
because of their design. They were designed to an exacting set of constraints. They
had to meet so-called Military Characteristics set forth by DOD in consultation with
DOE that specified safety parameters, weight, size, and yield, as well as the
conditions a warhead would encounter in its lifetime, such as temperature and
11 Sidney Drell, Raymond Jeanloz, et al., Remanufacture, MITRE Corporation, JASON
Program Office, JSR-99-300, October 1999, p. 4, 8.

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acceleration. Design compromises were made to meet these constraints. For
example, beryllium was used in warheads even though it is toxic and hard to
machine, and more energetic explosives were sometimes used instead of substantially
less energetic ones despite an increased safety risk. Design was usually done with
little consideration for ease of manufacture. Ambassador Linton Brooks, NNSA
Administrator, has said that to meet the various requirements, especially maximizing
yield while minimizing size and weight, “we designed these systems very close to
performance cliffs.”12 That is, designs approached the point at which warheads
would fail.13
A consequence of this design approach was that warhead components could be
hard to replicate. Indeed, according to Brooks, “it is becoming more difficult and
costly to certify warhead remanufacture. The evolution away from tested designs
resulting from the inevitable accumulations of small changes over the extended
lifetimes of these systems means that we can count on increasing uncertainty in the
long-term certification of warheads in the stockpile.”14
At issue is whether warheads can be maintained despite the absence of nuclear
testing by replacing deteriorated components with newly-made ones built as close as
possible to the original specifications. This debate has been going on for decades.
In a 1978 letter to President Carter, three weapons scientists argued that the United
States could go to great lengths in remanufacturing weapon components:
it is sometimes claimed that remanufacture may become impossible because of
increasingly severe restrictions by EPA or OSHA to protect the environment of
the worker. ... if the worker’s environment acceptable until now for the use of
asbestos, spray adhesives, or beryllium should be forbidden by OSHA
regulations, those few workers needed to continue operations with such material
could wear plastic-film suits ... It would be wise also to stockpile in appropriate
storage facilities certain commercial materials used in weapons manufacture
which might in the future disappear from the commercial scene.15
However, in a 1987 report, three scientists at Lawrence Livermore National
Laboratory stated:
12 U.S. Congress. Senate. Committee on Armed Services. Subcommittee on Strategic Forces.
Hearing: Strategic Forces/Nuclear Weapons Fiscal Year 2006 Budget, April 4, 2005.
Hereinafter “Senate Armed Services Committee hearing, Strategic Forces/Nuclear Weapons,
April 4, 2005.”
13 For example, if designers calculated that a certain amount of plutonium was the minimum
at which the warhead would work, they might add only a small extra amount as a margin of
assurance.
14 Brooks statement to Senate Armed Services Committee, April 4, 2005, p. 3.
15 Letter from Norris Bradbury, J. Carson Mark, and Richard Garwin to President Jimmy
Carter, August 15, 1978, reprinted in U.S. Congress. House. Committee on Foreign Affairs
and Its Subcommittee on Arms Control, International Security and Science, Proposals to
Ban Nuclear Testing, hearings and markup on H.J.Res. 3, 99th Congress, 1st Session, 1985,
p. 215.

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CRS-8
! Exact replication, especially of older systems, is impossible. Material
batches are never quite the same, some materials become unavailable, and
equivalent materials are never exactly equivalent. “Improved” parts often
have new, unexpected failure modes. Vendors go out of business ...
! Documentation has never been sufficiently exact to ensure replication. ...
We have never known enough about every detail to specify everything that
may be important. ...
! The most important aspect of any product certification is testing; it
provides the data for valid certification.16
Clearly, if components could be remanufactured to identical specifications,
using identical materials, indefinitely, then warheads could be maintained in this
manner as long as needed, with little in the way of scientific advances required. But
NNSA holds that a more comprehensive program is needed.
The Solution So Far: The Life Extension Program
With the end of the Cold War, the nuclear weapons complex, like the rest of the
defense establishment, faced turmoil. Budgets and personnel were slashed, design
of new weapons ended, and a test moratorium began. For a time, the chief concern
of DOE’s nuclear weapons management was survival of the nuclear weapons
complex.
To address this concern and set a course for the nuclear weapons enterprise,
Congress, in Section 3138 of P.L. 103-160, the FY1994 National Defense
Authorization Act, directed the Secretary of Energy to “establish a stewardship
program to ensure the preservation of the core intellectual and technical
competencies of the United States in nuclear weapons, including weapons design,
system integration, manufacturing, security, use control, reliability assessment, and
certification.” Since then, the Clinton and Bush Administrations have requested, and
Congress has approved, tens of billions of dollars for this Stockpile Stewardship
Program (SSP), which is presented in NNSA’s budget as “Weapons Activities.”
SSP uses data from past nuclear tests, small-scale laboratory experiments, large-
scale experimental facilities, examination of warheads, and the like to improve
theoretical understanding of the science underlying nuclear weapons performance.
In turn, it uses this knowledge to improve computer “codes” that simulate aspects of
weapons performance, revealing aspects of this performance and filling gaps in the
nuclear weapons laboratories’ understanding of it. Such advances enable scientists
to analyze data from past nuclear tests more thoroughly, “mining” it to extract still
more information. Theory, simulation, and data reinforce each other: theory refines
16 George Miller, Paul Brown, and Carol Alonso, Report to Congress on Stockpile
Reliability, Weapon Remanufacture, and the Role of Nuclear Testing, Lawrence Livermore
National Laboratory report UCRL-53822, October 1987, p. 25. For an opposing view, see
R.E. Kidder, Maintaining the U.S. Stockpile of Nuclear Weapons During a Low-Threshold
or Comprehensive Test Ban, Lawrence Livermore National Laboratory report UCRL-53820,
October 1987, esp. p. 6-9. See also U.S. Congress. Congressional Research Service.
Nuclear Weapons Production Capability Issues, CRS Report 98-519 F, June 8, 1998, by
Jonathan Medalia, esp. p. 97-102.

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simulation, simulation helps check theory, theory and simulation guide researchers
to look for certain types of data, and data help check simulation and theory.
A key task of the weapons complex is to monitor warheads for signs of actual
or future deterioration. This work is done through a program that conducts routine
surveillance of warheads in the stockpile by closely examining 11 warheads of each
type per year to search for corrosion, gases, and other evidence of deterioration. Of
the 11, one is taken apart for destructive evaluation, while the other 10 are evaluated
nondestructively and returned to the stockpile.17 In addition, an Enhanced
Surveillance Program (ESP) supports surveillance; its goal “is to develop diagnostic
tools and predictive models that will make it possible to analyze and predict the
effects that aging may have on weapon materials, components, and systems.”18
When routine surveillance detects warhead problems, the nuclear weapons
program applies knowledge gained through SSP to fix problems through the Life
Extension Program (LEP). It attempts “to extend the stockpile lifetime of a warhead
or warhead components at least 20 years with a goal of 30 years”19 in addition to the
originally-anticipated deployment time.
A warhead’s components may be divided into two categories: those that are part
of the nuclear explosive package (NEP), and those that are not. As described in the
Appendix, the NEP is the part of the warhead that explodes, as distinct from the more
numerous components like the outer case or arming system. Because non-NEP
components can be subjected to extensive experiments and nonnuclear laboratory
tests, they can be modified as needed under LEP to incorporate more advanced
electronics or better materials. In sharp contrast, NEP components cannot be
subjected to nuclear tests because the United States has observed a moratorium on
nuclear testing since 1992. As a result, LEP seeks to replicate these components
using original designs and, insofar as possible, original materials. In this way, it is
hoped, components will be close to the originals so that they can be qualified for use
in warheads. Because NEP components cannot be tested while other components can
be, long-term concern for both LEP and RRW focuses on NEP components.
Warheads contain several thousand components. While not all need to be
refurbished in an LEP, some are difficult to fabricate. As a result, the LEP for a
particular warhead is a major campaign with extensive preparatory analysis and
detailed work on many components that can take many years. For example, NNSA
describes the LEP for the W76 warhead for Trident submarine-launched ballistic
missiles as follows:
The W76 Life Extension Program will extend the life of the W76 for an
additional 30 years with the FPU [first production unit] in FY 2007. Activities
will include design, qualification, and certification activities to ensure the design
17 Information provided by NNSA, May 9, 2005.
18 Katie Walter, “Enhanced Surveillance of Aging Weapons,” Science & Technology
Review, January/February 1998: 21.
19 Department of Energy, FY2006 Congressional Budget Request, Volume I, p. 75. For a
weapon-by-weapon description of LEP activities planned for FY2006, see ibid., p. 75-76.

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CRS-10
of the refurbished warheads meets all required military characteristics; work
associated with the manufacturability of the components including the nuclear
explosive package; the Arming, Fuzing, and Firing (AF&F) system; the gas
transfer system; and the associated cables, elastomers, valves, pads, foam
supports, telemetries, and miscellaneous parts.20
Stockpile Stewardship has made great strides in understanding weapons science,
in predicting how weapons will age, and in predicting how they will fail. Most
observers agree with the following assessment by Brooks in congressional testimony
of April 2005:
today stockpile stewardship is working, we are confident that the stockpile is safe
and reliable, and there is no requirement at this time for nuclear tests. Indeed, just
last month, the Secretary of Energy and Secretary of Defense reaffirmed this
judgment in reporting to the President their ninth annual assessment of the safety
and reliability of the U.S. nuclear weapons stockpile. ... Our assessment derives
from ten years of experience with science-based stockpile stewardship, from
extensive surveillance, from the use of both experiments and computation, and
from professional judgment.21
Is LEP Satisfactory for the Long Term?
In the turmoil following the end of the Cold War, it is scarcely surprising that
the method chosen to maintain the stockpile — a task that had to be performed in the
face of the many changes affecting the weapons complex, and the many unknowns
about its future — was to minimize changes. Now, with SSP well established,
NNSA feels that it is appropriate to use a different approach to warhead maintenance,
one that builds on the success of SSP but that challenges the notion underlying LEP
that changes must be held to a minimum.
Advocates of RRW recognize that LEP has worked well but, as discussed
below, charge that it uses the wrong methods to maintain the wrong stockpile. Their
concern is not with maintaining reliability of warheads over the near term, but of
sustaining reliability over the long term. They assert that LEP is not suited to the
task because it will become harder to make it work as the universe in which current
warheads were created increasingly recedes from current technology. A universe of
archaic technology, it is argued, will become increasingly difficult to support as
materials, equipment, processes, and skills become unavailable. If the labs were to
lose confidence that they could replicate NEP components to near-original designs
using near-original materials and processes, the United States could ultimately face
a choice between resuming nuclear tests or accepting reduced confidence in
reliability.
Criticism of LEP starts with a particular view of nuclear strategy and the nuclear
stockpile. The current stockpile, most units of which were manufactured between
1979 and 1989, was designed to deter and, if necessary, defeat the Soviet Union.
20 Department of Energy, FY2006 Congressional Budget Request, Volume I, p. 75.
21 Brooks statement to Senate Armed Services Committee, April 4, 2005, p. 2. Original
emphasis.

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CRS-11
Now, as noted, threat, strategy and missions have changed. Accordingly, in this
view, the United States has the wrong stockpile for current circumstances. Brooks
said that current warheads are wrong technically because “we would [now] manage
technical risk differently, for example, by ‘trading’ [warhead] size and weight for
increased performance margins, system longevity, and ease of manufacture.” These
warheads were not “designed for longevity” or to minimize cost, and may be wrong
militarily because yields are too high and “do not lend themselves to reduced
collateral damage.” They also lack capabilities against buried targets or biological
and chemical munitions, and they do not take full advantage of precision guidance.22
Furthermore, LEP’s critics believe the stockpile is wrong politically because it is too
large:
We retain “hedge” warheads in large part due to the inability of either today’s
nuclear infrastructure, or the infrastructure we expect to have when the stockpile
reductions are fully implemented in 2012, to manufacture, in a timely way,
warheads for replacement or for force augmentation, or to act to correct
unexpected technical problems.23
Finally, they believe the stockpile is wrong in terms of physical security because it
was not designed for a scenario in which terrorists seize control of a nuclear weapon
and try to detonate it in place. New use control technologies would permit NNSA
to reduce the cost of “gates, guns, guards.”24
RRW and the Transformation of Nuclear Warheads
The U.S. nuclear stockpile was designed within Cold War constraints,
requirements, and opportunities. While the requirement for warheads to be safe and
reliable remains constant, many other constraints have changed — indeed, inverted
— over the past 15 years, and new opportunities and requirements have emerged as
well. As a result, RRW advocates claim, it is both necessary and feasible to
transform the stockpile to reflect these changes.
With RRW, NNSA hopes to revisit tradeoffs underlying the current stockpile
to enable it to adapt to changes over the past 15 years and meet possible future
requirements. While RRW would change many tradeoffs significantly, the changes
would, in NNSA’s view, work out well: NNSA would trade negligible sacrifices to
secure major gains. For example, NNSA would consider relaxing constraints on
yield and yield-to-weight, assuming DOD approved. So doing would enable NNSA
to move to simpler designs, which would be essential in an environment without
nuclear testing. NNSA would strive to minimize the use of hazardous materials, and
relaxing constraints on yield and on yield to weight would make it easier to do so.
The balance of this section presents some Cold War warhead requirements, how they
have changed, and implications of these changes.
22 Ibid., pp. 2-3.
23 Ibid., p. 3.
24 Ibid., p. 4.

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CRS-12
Efficiency. A major characteristic of warheads for ballistic and cruise missiles
was a high “yield-to-weight ratio” — that is, maximizing a warhead’s explosive force
(yield) for a given weight.25 Reducing weight let each missile carry more warheads
to more distant targets; increasing yield gave each warhead a better chance of
destroying its target; and increasing yield-to-weight enabled these goals to be met at
the same time. For example, the W88 warhead for the Trident II submarine-launched
ballistic missile, used a conventional high explosive (CHE) that was more sensitive
to impact than an alternative, insensitive high explosive (IHE), used on many other
warhead types. IHE provided greater safety, but CHE packed substantially more
energy per unit weight. A missile could carry the lighter CHE warheads to a greater
distance, so that a submarine could stand off farther from its targets. Increased ocean
patrol area forced the Soviet Union to spread out its antisubmarine assets, improving
submarine survivability. Hard-to-manufacture designs, hazardous materials, and
other undesirable features were deemed acceptable design tradeoffs to maximize
yield-to-weight. Now, ballistic missiles carry fewer warheads than they did during
the Cold War due to reduced targeting requirements. As a result, it is possible to
revisit the Cold War tradeoffs, redesigning warhead components to give greater
emphasis to other characteristics at the expense of yield, weight, or both. For
example, with a missile’s carrying capacity divided among fewer warheads, each
warhead can be somewhat heavier,26 and the added permissible weight might be
allocated to a design that was easier to manufacture.
Yield. During the Cold War, DOD required a substantial yield for its strategic
warheads. Yield compensated for inaccuracy in attacking targets such as missile
silos, which were hardened to withstand all but near misses or direct hits. Yield was
also important for attacking targets covering large areas, such as shipyards or
petroleum refineries. Now, high yield is much less important. It is unclear what area
targets there might be in the future. Further, precision guidance enables conventional
bombs to score direct hits on targets, and similar technology could apparently be used
to make missile-delivered nuclear warheads more accurate, permitting lower yield.
Indeed, some argue that the United States needs some lower-yield warheads.27 In this
view, lower-yield warheads would create less of the unintended damage that might
prevent the United States from using them. Such warheads would be a better
deterrent precisely because their use would be more credible.
25 Bombs were less constrained in weight because bombers carry heavier loads than missiles.
26 Ballistic missiles carry warheads inside reentry vehicles (RVs). An RV is a streamlined
shell that protects its warhead from the intense heat and other stresses of reentering the
atmosphere at high speed. RVs are designed to carry a specific type of warhead on a
specific missile; the maximum stress that the RV encounters is carefully studied. Increasing
warhead weight significantly would increase these stresses, possibly causing the RV to fail
and the warhead to burn up, fail, or miss its target by a wide margin.
27 Bryan Fearey, Paul White, John St. Ledger, and John Immele, “An Analysis of Reduced
Collateral Damage Nuclear Weapons,” Comparative Strategy, October/November 2003:
313-315. These lower-yield weapons are not necessarily the very low yield “mini-nukes”
debated in Congress in recent years.

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Nuclear testing. Between 1945 and 1992, the United States conducted over
1,000 nuclear tests, most of which were for weapons design.28 These tests provided
confidence that a weapon incorporating hard-to-manufacture components was made
correctly, that a weapon would work at the extremes of temperatures to which it
might be exposed, and that the design was satisfactory in other ways. Testing also
enabled the labs to validate changes to existing warhead designs. With the
congressionally-imposed U.S. nuclear test moratorium in October 1992,29 the United
States can no longer rely on tests to validate designs. While there are no military
requirements for nuclear weapons with new or modified military capabilities,30 any
future weapon would have to be more conservatively designed, staying within design
parameters validated by past nuclear tests. This conservatism applies as well to
modifications of components.
Performance, schedule, and cost tradeoffs. Performance has always been the
dominant consideration for nuclear weapons. Weapons must meet standards for
safety and reliability, and meet other military characteristics. During the Cold War,
schedule was also critical. With new missiles and nuclear-capable aircraft entering
the force at a sustained pace, warheads and bombs had to be ready on a schedule
dictated by their delivery systems. As a result, “our nuclear warheads were not
designed ... to minimize DOE and DoD costs.”31 Now, reducing cost has a higher
priority. Cost reduction is also more feasible: performance is still dominant, but no
external threat drives the schedule.
Environment, safety, and health (ES&H). During much of the Cold War, the
urgency of production and the limited knowledge of the ES&H effects of materials
used or created in the nuclear weapons enterprise resulted in the use of hazardous
materials, dumping contaminants onto the ground or into rivers, exposing citizens to
radioactive fallout from nuclear tests, and the like. Now, ES&H concerns have
grown within the nuclear weapons complex, reflecting their rise in civil society at
large, leading to a strong interest in minimizing the use of hazardous materials in
warheads and their production.
Skill development and transfer. During the Cold War, the design of dozens of
warhead types, the conduct of over 1,000 nuclear tests, and the production of
thousands of warheads exercised the full range of nuclear weapon skills. Now, with
no design or testing, no new-design warheads being produced, and with warheads
28 The United States conducted 1,030 tests, of which 883 were weapons related. (The
United Kingdom conducted another 24 tests at the Nevada Test Site.) U.S. Department of
Energy. Nevada Operations Office. Office of External Affairs. United States Nuclear Tests,
July 1945 through September 1992, DOE/NV-209, revision 14, December 1994, p. viii.
29 The moratorium was begun pursuant to Section 507 of P.L. 102-377, FY1993 Energy and
Water Development Appropriations Act, signed into law October 2, 1992.
30 Brooks stated, “we must preserve the ability to produce weapons with new or modified
military capabilities if this is required in the future. Currently the DoD has identified no
requirements for such weapons, but our experience suggests that we are not always able to
predict our future requirements.” Brooks statement to Senate Armed Services Committee,
April 4, 2005, p. 6. Emphasis added.
31 Brooks statement to Senate Armed Services Committee, April 4, 2005, p. 3.

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CRS-14
being refurbished at a slower pace than that at which they were originally produced,
some have raised concern that weapons complex personnel are not adequately
challenged. In this view, skill development and transfer can no longer be simply a
byproduct of the work, but must be an explicit goal of the nuclear weapons program.
RRW and the Transformation of the Nuclear Weapons
Enterprise
Supporters see RRW as the basis for much more than addressing warhead
issues. Representative Hobson was, as noted, the prime sponsor of the effort to
establish RRW. Consequently, it is important to understand his intent for the
program. He expressed concern about the direction of nuclear policy. In introducing
the FY2005 energy and water bill to the House, he emphasized the need to redirect
the nuclear weapons complex:
much of the DOE weapons complex is still sized to support a Cold War
stockpile. The NNSA needs to take a ‘time-out’ on new initiatives until it
completes a review of its weapons complex in relation to security needs, budget
constraints, and [a] new stockpile plan..32
At a National Academy of Sciences symposium in August 2004, he expressed
concern about Administration nuclear policies and programs:
I was not comfortable with the Administration’s emphasis on new nuclear
weapons initiatives in the fiscal year 2004 budget request and repeated in the
fiscal year 2005 request. I view the Advanced Concepts research proposal, the
Robust Nuclear Earth Penetrator study, and the effort to reduce the nuclear test
readiness posture to 18 months as very provocative and overly aggressive
policies that undermine our moral authority to argue that other nations should
forego nuclear weapons. We cannot advocate for nuclear nonproliferation
around the globe and pursue more useable nuclear weapon options here at home.
That inconsistency is not lost on anyone in the international community.33
He saw RRW as a key part of his effort to redirect U.S. nuclear strategy, reshape
the nuclear weapons stockpile and complex to support that strategy, undertake
weapons programs consistent with that strategy, and reject those inconsistent with it.
I think the time is now for a thoughtful and open debate on the role of nuclear
weapons in our country’s national security strategy. There is still a basic set of
questions that need to be addressed and let me talk about some of those. How
large a stockpile should we maintain, should we have a set of older weapons with
many spares or should we have a smaller stockpile of more modern weapons?
32 U.S. Congress. Congressional Record. June 25, 2004: H5085.
33 Representative David Hobson, “Remarks by Chairman David Hobson — House
Appropriations Subcommittee on Energy and Water Development, [to the] National
Academy of Sciences, Committee on International Security and Arms Control, Symposium
on ‘Post-Cold War U.S. Nuclear Strategy: A Search for Technical and Policy Common
Ground,’” August 11, 2004, p. 3; available at [http://www7.nationalacademies.org/cisac/
Hobson_Presentation.pdf].

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CRS-15
What design and manufacturing capabilities do we need to maintain the DOE
nuclear weapons complex? And where should these complexes be located? And
finally, is this the best use of our limited, financial resources for national
defense? ... until we have this debate and develop a comprehensive plan for the
U.S. nuclear stockpile and the DOE weapons complex, we’re left arguing over
isolated projects such as the robust nuclear penetrator or the RNEP study. ...34
Representative Hobson also stated:
The Reliable Replacement Warhead concept will provide the research and
engineering problems necessary to challenge the workforce while at the same
time refurbishing some existing weapons in the stockpile without developing a
new weapon that would require underground testing to verify the design. A more
robust replacement warhead, from a reliability standpoint, will provide the
stockpile hedge that is currently provided by retaining thousands of unnecessary
warheads.35
Thus while the FY2005 omnibus appropriations conference report and NNSA’s
FY2006 budget request presented a program of narrow scope, Representative Hobson
envisioned that RRW could be much more consequential. NNSA Administrator
Linton Brooks agreed. In testimony of April 2005, he presented an expansive view
of the transformation of the nuclear weapons enterprise, with RRW as its pivot point.
Let me briefly describe the broad conceptual approach for stockpile and
infrastructure transformation. The “enabler” for such transformation, we believe,
is the RRW program. To establish the feasibility of the RRW concept, we will
use the funds provided by Congress last year and those requested this year to
begin concept and feasibility studies on replacement warheads or warhead
components that provide the same or comparable military capabilities as existing
warheads in the stockpile. If those studies suggest the RRW concept is
technically feasible, and if, as I expect, the Department of Defense establishes
a requirement, we should be able to develop and produce by the 2012-15
timeframe a small build of warheads in order to demonstrate that an RRW system
can be manufactured and certified without nuclear testing.
Once that capability is demonstrated, the United States will have the option to:
• truncate or cease some ongoing life extension programs for the legacy
stockpile,
• apply the savings from the reduced life extension workload to begin to
transform to a stockpile with a substantial RRW component that is both easier
and less costly to manufacture and certify, and
• use stockpile transformation to enable and drive consolidation to a more
responsive infrastructure.36
34 Congressman David Hobson, “U.S. Nuclear Security in the 21st Century,” address to the
Arms Control Association, Washington, DC, February 3, 2005. (transcript as delivered)
35 Congressman David Hobson, “U.S. Nuclear Security in the 21st Century,” address to the
Arms Control Association, Washington, DC, February 3, 2005 (remarks as prepared for
delivery).
36 Brooks statement to Senate Armed Services Committee, April 4, 2005, p. 6.

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CRS-16
DOD, as the “customer” and potential user of nuclear weapons, sets
requirements for types and characteristics of nuclear weapons. Representatives of the
Office of the Secretary of Defense, the armed services, and NNSA participate in the
Nuclear Weapons Council, which under 10 U.S.C. 179 coordinates their efforts in
this area. Clearly, if RRW is to progress, it would need the participation and support
of DOD, the services, and NNSA. A first step in that direction occurred in March
2005 when the council, by unanimous vote, fully supported the RRW concept. At
the same time, RRW, like any program, is subject to congressional approval,
rejection, or modification.
Steve Henry, Deputy Assistant to the Secretary of Defense for Nuclear Matters,
provided the following statement. It is the first detailed statement of DOD’s position
on RRW:37
President Bush said, “I am committed to achieving a credible deterrent with
the lowest possible number of nuclear weapons consistent with our national
security needs, including our obligations to our allies. My goal is to move
quickly to reduce nuclear forces.”38 To achieve this goal, we must have
confidence in the safety, security, and reliability of the weapons not just for
today, but for the long term and with the goal to reduce the likelihood of
resumption of nuclear testing.

Our current path does not adequately meet the President’s guidance. The
current stockpile was built in the 80’s. These weapons are optimized for yield-
to-weight and were expected to remain in the stockpile for only about 20 years.
Under the current life extension program, these weapons would be refurbished
to extend their life for more than 30 years beyond their original design life.
Although any change to a weapon component is reviewed extensively, there
remains an uncertainty on the potential impact of cumulative changes.
Fundamentally, the life extension program would continue the reliance on Cold
War legacy designs that use toxic and high risk materials and provide only
limited opportunity to enhance safety and security with 21st century technology.
Additionally, in some cases, the life extension program would require the
reconstitution of expensive weapons production processes that were discontinued
more than a decade ago. Under the current path, the DoD would continue to
depend on non-deployed warheads to hedge against technical failures and against
geopolitical changes.
It is in the best interest of the United States to pursue an alternate path. In
concept, a reliable replacement warhead (RRW) could provide that path. Ideally,
RRW would sustain the military capabilities of the existing stockpile but may
require relaxing some of the Cold War design requirements in order to use
replacement components. These components would be designed to increase
margins, provide for ease of manufacture and certification, and would reduce the
potential for failure due to design and manufacturing flaws and material aging
issues. These RRW characteristics would improve our ability to ensure
long-term confidence in the stockpile and reduce the likelihood of resumption of
nuclear testing, therefore potentially reducing the number of warheads needed
37 Statement provided to the author May 3, 2005.
38 President George W. Bush, Remarks by the President to Students and Faculty at National
Defense University, Fort Lesley J. McNair, Washington, D.C., May 1, 2001.

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CRS-17
to hedge against technical surprises. Under the RRW concept, incorporation of
modern safety and security technology would be feasible. RRW could be the
enabler for the transformation to an efficient, responsive infrastructure, which
may help reduce the number of warheads needed to hedge against geopolitical
changes. As an example of how it would make manufacturing easier while
increasing safety within the nuclear weapons complex, it could eliminate the
need for many of the exotic and hazardous non-nuclear materials.
RRW would, in concept, offer other advantages as well, such as the
opportunity to exercise and transfer expertise. However, if we want to move
from our current path to RRW, we must do it soon because experienced nuclear
weapon designers with test experience are rapidly retiring.
The U.S. Strategic Command (STRATCOM), a component of DOD, is the
military command that operates and, at the President’s direction, would use U.S.
strategic nuclear forces. It provided the following statement on RRW: “STRATCOM
will be participating in the joint RRW Project Officers Group, or POG, with the
NNSA, the Navy, and the Air Force, and STRATCOM’s position on RRW will be
based on the results of the RRW POG process.”39
Skeptics’ Views of RRW
Because RRW is new, not clearly defined, and may hold benefits as well as
costs, those who have criticized some past nuclear weapon programs are trying to
understand RRW and its implications better. Because they are in the process of
shaping their views, there are few outright critics of the program, but some skeptics.
Some Members of Congress take a cautious approach. A letter drafted by
Representative Tauscher and others to Representatives C.W. Bill Young and David
R. Obey, Chairman and Ranking Member, respectively, of the House Appropriations
Committee, and signed by at least 51 Members of Congress, states that RRW “was
added in the Omnibus Conference last year to replace Advanced Concepts. The scope
and direction of this program must be clearly defined so that this program does not
simply replace the one Congress canceled last year.” Further, “We are also
concerned that shifting funding from the cancelled Advanced Concepts program into
the Reliable Replacement Warhead program may result in new nuclear warheads
moving forward without any established need or compelling justification.”40
Robert Peurifoy, a former Vice President of Sandia National Laboratories, feels
RRW has been oversold. He sees little difference between RRW and LEP; if a
component can be manufactured with materials different than the original under
RRW, for example, why couldn’t that be done under LEP? He notes that that the
labs, using development, production, and stockpile data, have repeatedly certified the
reliability for the nuclear explosive package of warheads at 100 percent; how, he
asks, can that be improved upon? If stockpile stewardship, including LEP as one of
its tools, can maintain warheads for nine years without testing, why can it not do so
39 Information provided by STRATCOM to the author, April 29, 2005.
40 Letter provided by Representative Tauscher’s office; used by permission. For full text,
see [http://www.ananuclear.org/markeys%20letter.html].

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CRS-18
indefinitely? The lack of a military requirement for new-design warheads for many
years, and the questionable rationales presented for such warheads in the public
debate, in his view, undermines the need for a “responsive” infrastructure, as there
will likely be few if any events requiring a response.41
Raymond Jeanloz is a Professor of Earth and Planetary Science and of
Astronomy at the University of California, Berkeley, and a long-time member of
scientific panels reporting on nuclear-weapon issues. His view depends on what
RRW is. He supports a version of RRW that would build on the success of SSP to
improve manufacturing practices, lower costs and increase performance margins, as
these enhancements would support the Administration’s decision to significantly
reduce the size of the U.S. stockpile. This RRW would stay within the design
parameters that have been validated by nuclear testing. In contrast, he opposes an
RRW that would move beyond those parameters in order to create new weapons, as
that approach could lead to new weapons that are less reliably validated, that require
testing, and that would counter U.S. nonproliferation efforts. In particular, he
believes that new designs would undermine U.S. attempts to convince other nations
not to develop nuclear weapons by showing them that the United States still feels the
need for new weapons. Whichever form of RRW emerges, Jeanloz is concerned
about the lack of clarity regarding the program and its cost.42
Sidney Drell, Professor Emeritus of Physics at Stanford University, and James
Goodby, who held several Administration positions in arms control, including
Special Representative of President Clinton for the security and dismantlement of
nuclear weapons from 1995 — 1996, both have a view of RRW that depends on how
technologically ambitious the program is:
One direct way to simplify the process of certifying the reliability and
effectiveness of the warheads and to sustain this confidence over a longer period
of time is to increase their performance margins. An example of this is to further
enhance the explosive energy provided by the primary stage of a nuclear weapon
above the minimum required to ignite the secondary, or main, stage of a nuclear
weapon. A straightforward way to do this that requires no explosive testing to
validate is by adjusting the boost gas fill in the primary during scheduled
maintenance or remanufacturing activities. This is an example of an existing
process for maintaining long-term high confidence in the arsenal. It is already
available, has high merit, and should continue to be implemented.7 This approach
is the appropriate focus of effort for the Reliable Replacement Warhead (RRW)
program currently being funded at the U.S. national weapons laboratories.
Turning the RRW program into an effort to develop new-warhead designs
by altering the nature of the high explosives or the amount of nuclear fuel in the
primary without testing, as some have suggested, would be a mistake. It takes an
extraordinary flight of imagination to postulate a modern new arsenal composed
of such untested designs that would be more reliable, safe, and effective than the
41 These views are drawn from discussions and emails between Mr. Peurifoy and the author,
March-April 2005.
42 These views are drawn from discussions and emails between Professor Jeanloz and the
author, March-April 2005.

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current U.S. arsenal based on more than 1,000 tests since 1945. A comprehensive
and rigorous stockpile maintenance program confirms and sustains this high
confidence. If testing is resumed, the damage to the broader nonproliferation
regime, and thus to U.S. security interests, would far outweigh any conceivable
advantages to be gained from the new designs.43
Daryl Kimball, Executive Director of the Arms Control Association, is more
concerned:
the [RRW] proposal is problematic. The rationale for the program is dubious, the
scope is vague, and the potential effects far-reaching and dangerous. ... new
replacement warheads are not necessary to preserve existing U.S.
nuclear-weapon capabilities. ... the existing Stockpile Stewardship Program is
working. ... the RRW program could, if not carefully circumscribed, become a
back door for the administration to circumvent congressional opposition to new
warhead designs for new and destabilizing nuclear strike missions. ... replacing
existing, well-proven nuclear warhead designs with “new” and “improved”
replacement warheads or warhead components could, if carelessly pursued,
increase pressure to conduct nuclear explosive proof tests. ... So long as the
United States maintains a nuclear arsenal, stockpile maintenance efforts should
focus on preserving the reliability of existing warheads using methods validated
by past experience.44
Issues for Congress
Are the Surveillance Program and LEP Sufficient to Maintain the
Stockpile? Skeptics hold that LEP works now, can work indefinitely, and should
improve over time. A 2002 report by the National Academy of Sciences stated:
we see no reason that the capabilities of those mechanisms [for maintaining
confidence in the stockpile] — surveillance techniques, diagnostics, analytical
and computational tools, science-based understanding, remanufacturing
capabilities — cannot grow at least as fast as the challenge they must meet.
(Indeed, we believe that the growth of these capabilities — except for
remanufacturing of some nuclear components — has more than kept pace with
the growth of the need for them since the United States stopped testing in 1992,
with the result that confidence in the reliability of the stockpile is better justified
technically today than it was then.)45
43 Sidney Drell and James Goodby, What Are Nuclear Weapons For? Recommendations for
Restructuring U.S. Strategic Nuclear Forces, Arms Control Association, April 2005, p. 19-
20. Footnote in original is as follows: 7. Executive Summary, JASON Report on Nuclear
Testing, JSR-95-320 (August 1, 1995).
44 Daryl Kimball, “Replacement Nuclear Warheads? Buyer Beware,” Arms Control Today,
May 2005.
45 National Academy of Sciences. Committee on Technical Issues Related to Ratification
of the Comprehensive Nuclear Test Ban Treaty. Technical Issues Related to the Compre-
hensive Nuclear Test Ban Treaty. Washington, National Academy Press, 2002, p. 5.

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Skeptics argue that SSP can accommodate minor variance in components made
with LEP. Variation has always been present in nuclear weapons production. During
the Cold War, when thousands of warheads of a given type were made over a period
of years, small changes were inevitable: materials would vary from one batch to the
next, vendors would reformulate materials slightly, processes were not completely
defined, and minor design or process changes were made. While nuclear testing was
available, it was impossible to test all variations. Despite these limitations, weapons
were certified for use in the stockpile, indicating that some variance is acceptable.
RRW supporters argue that LEP will have increasing difficulty in maintaining
weapons over the long term, as discussed in “Is LEP Satisfactory for the Long
Term?” Regarding testing, it was unnecessary to test all variance between warheads
because much of it fell within design parameters validated by nuclear tests. At the
same time, testing was available to address uncertainties and to provide confidence
in larger changes.
Is RRW Needed in Order to Provide New Military Capabilities?
NNSA Administrator Brooks maintains that the current stockpile may be wrong from
a military perspective. Yields are too high, there is potential for too much collateral
damage, we lack the capability to destroy buried facilities or facilities containing
chemical or biological weapons, warheads could be more accurate, and they are not
geared for small-scale strikes. Weapons to create electromagnetic pulse to destroy
electronic equipment would be more effective if their radiation outputs were tailored
to the mission, which could require modifications to the NEP. Weapons to destroy
chemical or biological weapons would benefit from altered radiation outputs. Brooks
said, “we must preserve the ability to produce weapons with new or modified military
capabilities if this is required in the future.” He views RRW as the “enabler” for
transforming the stockpile.
RRW skeptics would challenge the need for new military capabilities. They
maintain that current weapons possess a vast range of capabilities that should suffice
for the limited contingencies in which the United States might use them. Brooks
does not claim that new capabilities are needed, only that they might be in the future.
Further, they argue, many of Brooks’s examples are irrelevant to RRW. Accuracy
depends mainly on the reentry vehicle and the missile’s guidance. The ability to
conduct small strikes depends on command and control. There may be various ways
to reduce the yield, and collateral damage, of existing weapons. Unmodified weapons
can generate electromagnetic pulse, as has been known since around 1960.46 Even
modified nuclear weapons may be unable to destroy chemical or biological agents in
46 U.S. Department of Defense and Department of Energy. The Effects of Nuclear Weapons.
Compiled and edited by Samuel Glasstone and Philip Dolan. Washington, USGPO, 1977,
p. 514.

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CRS-21
buried facilities.47 Accordingly, critics challenge the new-capabilities argument as
a rationale for RRW.
Might RRW Permit a Reduction in Warhead Numbers? The United
States retains many reserve warheads. Some are for inspection. Some hedge against
a potential need for more deployed weapons, which is important because the United
States has been unable to produce weapons for the stockpile since shortly after the
Rocky Flats pit production plant closed in 1989. (See Appendix.) Others hedge
against the failure of some weapons; for example, NNSA retains at least two warhead
types for each delivery system — W62, W78, and W87 for land-based missiles, W76
and W88 for submarine-launched missiles, B61 and B83 bombs for aircraft, and W80
and W8448 for cruise missiles. In that way, the failure of one warhead type would not
compel the withdrawal of an entire class of delivery systems. Still others insure
against an inability by NNSA to maintain the stockpile with LEP. While all units of
a given warhead type age at the same rate, individual units differ slightly, so may fail
at different times or for different reasons.

In the view of DOD and NNSA, RRW would permit a reduction in warhead
numbers by increasing confidence in the warheads that remain. It would also support
a production complex that can demonstrate the capability to manufacture at least
small numbers of warheads for the stockpile. In that way, the United States could
respond to new military requirements with new-production RRW warheads that
might be tailored for specific missions rather than maintaining large numbers of
stockpiled warheads, at substantial cost, in which confidence might erode over time.
RRW supporters believe that RRW creates an additional path, beyond that
offered by LEP, for increasing confidence in warheads. They state that, under LEP’s
approach of minimizing changes to the nuclear explosive package (NEP), problems
can only be resolved by attempting to reduce uncertainties through technical analyses,
while RRW also provides the option of increasing margins by redesigning
components to compensate for uncertainties.49
47 A National Academy of Sciences report stated, “An attack [on a chemical or biological
weapons facility] by a nuclear weapon would be effective in destroying the agent only if
detonated in the chamber where agents are stored,” and that the uncertainty of survival of
an earth penetrator weapon increases with a depth of penetration greater than 3 meters.
National Academy of Sciences. National Research Council. Division on Engineering and
Physical Sciences. Committee on the Effects of Nuclear Earth-Penetrator and Other
Weapons. Effects of Nuclear Earth-Penetrator and Other Weapons. Washington, National
Academies Press, 2005; prepublication copy, p. 9-1 and 9-2. By this reasoning, a nuclear
attack on a chemical or biological weapon facility buried at a moderate depth would
probably fail.
48 The W84 is not in the active stockpile.
49 The weapons labs are developing a technique, quantification of margins and uncertainties
(QMU), to evaluate how changes affect weapon performance. The idea is to identify key
segments of a weapon’s performance (e.g., high explosive detonation), the minimum and
maximum values required for each segment to perform as intended, the range of uncertainty
associated with those values, and the design margins. Under QMU, the labs could have
confidence in the warhead if margin exceeds uncertainty at each segment. QMU could be
(continued...)

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Skeptics endorse stockpile reductions, but would question the need for RRW to
meet this goal. They argue that other means can maintain confidence in warheads.
For example, tritium gas, which is used to boost a weapon’s yield (see Appendix),
decays radioactively, so changing a weapon’s tritium more frequently could, it is
argued, compensate for uncertainties introduced by slight changes in weapon
components under LEP.50 This change can be made under LEP with no impact to the
NEP. Skeptics also point out that RRW would address only one of many reasons
given for a reserve stockpile, so it would seem that RRW by itself would not permit
large reductions.
RRW supporters agree that enhanced boost gas could forestall some problems
and should be used to do so, but note that it cannot solve others: a slight asymmetry
in the implosion wave might cause the primary to fail, or a failure of the radiation
case would prevent the secondary from detonating.
Will RRW Save Money? Supporters claim that RRW would save money for
the following reasons. Using fewer hazardous materials in components and
production processes would reduce the cost of handling, worker and environmental
protection, and waste disposal. Components designed for ease of production could
be produced with less equipment, in less time, and on less floor space. Components
less sensitive to minor variations in dimensions and materials would have fewer
production units rejected, reducing the waste stream and effectively increasing
capacity. Use of more advanced warhead use-control features would permit a
reduction in the cost of physical security. Increasing warhead safety would reduce
the risk of plutonium dispersal in a fire, and the resulting cost. Reducing stockpile
size would lower security and maintenance expenses.
Skeptics favor holding down costs, but not at the expense of confidence in the
stockpile. They place more confidence in LEP, and would rather use it even if it
costs more than RRW. They also anticipate that RRW would entail high transition
costs for development of warhead components and production processes,
construction of new nuclear weapons complex facilities, and modification of large
49 (...continued)
used with LEP or RRW. For more on QMU, see David Sharp and Merri Wood-Schultz,
“QMU and Nuclear Weapons Certification: What’s under the Hood,” Los Alamos Science,
number 28, 2003: 47-53; and D.H. Sharp, T.C. Wallstrom, and M.M. Wood-Schultz,
“Physics Package Confidence: ‘ONE’ vs. ‘1.0,’” Proceedings of the NEDPC [Nuclear
Explosives Design Physics Conference] 2003, Los Alamos report LAUR-04-0496, 13 p.
50 “In certain cases, slight changes in the attributes of a nuclear weapons component, such
as those introduced by using new technologies, can be rendered unimportant by increasing
the margin of performance of the weapon. By margin of performance, we mean the
difference in primary yield which is expected from a normal weapon and the minimum
primary yield which will drive the secondary to essentially full yield. The margin available
to a specific weapon changes with time and circumstances, notably because primary yield
is so sensitively dependent on the amount of tritium available in the gas system. ... There are
various means to enhance the margin without resorting to underground tests ... But it seems
clear that the most significant opportunity to enhance margin lies in the gas supply system.
... one obvious means is to shorten the tritium refill cycle so that large excursions in the
amount of tritium do not occur.” Drell, Jeanloz, et al., Remanufacture, p. 23-24.

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CRS-23
numbers of warheads. Posited savings from RRW in operations and maintenance,
corrected for inflation, would have to exceed these up-front investment costs for the
cost argument to be valid. With RRW at a preliminary stage, skeptics doubt that
RRW supporters have nearly enough data to make cost comparisons.
How Might RRW Affect the Nuclear Weapons Complex? A responsive
infrastructure, including the nuclear weapons complex, is an element of the New
Triad.51 Responsiveness appears to include flexibility, the ability to switch rapidly
from work on one warhead type to work on another in case a defect is found that
requires a prompt fix; timeliness, the ability to modify warheads or make new-design
warheads if needed in time to respond to potential threats, if called for by DOD; and
capacity adequate to make fixes in a reasonable time to a warhead type with many
deployed units, or so that it could work on several warhead types simultaneously.
A responsive infrastructure, RRW supporters believe, requires new-design
components. Components that are designed for ease of manufacture and that
minimize the use of hazardous materials would permit the plants to use simpler
production processes and produce at a faster rate. Conversely, by increasing
confidence, RRW could enable DOD to shift its hedge against potential weapon
problems from maintaining many inactive warheads to a more responsive
infrastructure, thereby reducing the number of nondeployed warheads and the size
of the complex needed to support the stockpile.
Skeptics would question whether an LEP infrastructure would be much less
responsive than an RRW infrastructure. New-design NEP components fully
supportable by nuclear test data could be done under LEP or RRW. The remaining
subset of components, new-design NEP components not fully supported by test data,
would involve considerable equipment and skill to produce even under RRW.
Worse, such components might introduce problems, and correcting them would
absorb much of the capacity of the infrastructure, reducing its responsiveness.
Finally, responsiveness can be gained in ways other than component design, such as
by investment in equipment, facilities, and R&D on manufacturing. Skeptics do not
oppose all manufacturing improvements. Some improvements could produce
components to tighter tolerances, reducing variations that might raise questions about
reliability. Skeptics see a smaller stockpile as the best way to assure responsiveness
by easing the burden on the production complex.
Skeptics may find the nuclear weapons complex envisioned by NNSA
Administrator Brooks under RRW to be troubling:
Establishing a responsive nuclear infrastructure will provide opportunities for
additional stockpile reductions because we can rely less on the stockpile and
more on infrastructure (i.e., ability to produce or repair warheads in sufficient
quantity in a timely way) in responding to technical failures or new or emerging
threats.52
51 Crouch, Special Briefing on the Nuclear Posture Review, January 9, 2002.
52 Brooks statement to Senate Armed Services Committee, April 4, 2005, p. 3.

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If we can establish a responsive infrastructure and demonstrate we can produce
replacement warheads on the same time scale in which geopolitical threats
emerge — and if we can demonstrate that we can respond quickly to technical
problems, then I believe we can go much further in reducing nondeployed
warheads in order to meet the President’s stated vision of the smallest stockpile
consistent with our nation’s security requirements.53
Skeptics take these statements as evidence that RRW would entail a substantial
production capacity and the ability to design weapons and start production quickly,
thereby enabling the buildup of a larger stockpile if desired. They believe that some
manufacturing processes could be upgraded under LEP, and reject the implication
that only RRW could deliver a more efficient and responsive complex to support a
smaller stockpile.
RRW advocates, however, maintain that the United States needs a nuclear
weapons complex as Brooks described because it addresses contingencies that could
well arise. The United States may need to (1) design and produce new or modified
warheads quickly to meet new threats; (2) rebuild several warhead types at the same
time; (3) conduct a large-scale, rapid rebuild to correct a defect in a type of warhead
deployed in large numbers, and (4) rebuild a smaller stockpile on a continuing basis
to avoid issues that could cause uncertainty in performance, Substantial capacity is
needed to meet any of these goals, let alone all of them simultaneously. However,
they argue that this capacity does not mean that the United States will build a large
stockpile; the President and Congress would decide on stockpile size.
Might RRW Undermine U.S. Nonproliferation Efforts? Skeptics oppose
RRW to the extent that it entails a substantial production capacity, facilitates the
development of weapons with new military capabilities, or leads to testing. They are
concerned that a program of that sort may appear to run counter to the U.S.
commitment in Article VI of the Nuclear Nonproliferation Treaty (NPT) to “pursue
negotiations in good faith on effective measures relating to cessation of the nuclear
arms race at an early date and to nuclear disarmament ...” Further, a statement by
China, France, Russia, the United Kingdom, and the United States to the 2000 NPT
Review Conference reiterated “our unequivocal commitment to the ultimate goals of
53 Senate Armed Services Committee hearing, Strategic Forces/Nuclear Weapons, April 4,
2005.

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a complete elimination of nuclear weapons ...”54 In this view, reaffirming the value
of nuclear weapons through programs such as RRW would make it harder for the
United States to achieve its nonproliferation objectives diplomatically. Member
states of the NPT, meeting in New York in May 2005 to review treaty
implementation, have criticized the United States, though not by name, for nuclear
weapon programs, which they see as inconsistent with Article VI of the treaty.55
RRW’s supporters counter that RRW will increase confidence in the reliability
of weapons and in the ability to certify them over the long term. As a result, RRW
will reduce the probability that the United States will resume nuclear testing and will
permit a substantial reduction in the U.S. nuclear stockpile, both of which could have
a positive effect on nonproliferation. In addition, some may take the view that an
RRW program that facilitated the development of nuclear weapons with new military
missions could help dampen proliferation by strengthening deterrence.
Might LEP or RRW Lead to Nuclear Testing? RRW’s supporters and
skeptics both prefer to avoid nuclear testing. The Administration has continued the
54 “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,” introduced in “Statement to the 2000 NPT Review Conference,” by
H.E. Hubert de la Fortelle on behalf of the U.N. permanent five nuclear weapon states, May
1, 2000; available at [http://www.ceip.org/programs/npp/npt2000p5.htm].
55 See, for example, Ambassador Wernfried Koeffler, Head of Delegation, Austria, in a
statement to the 2005 NPT Review Conference (p. 4), said, “Our concern that nuclear
weapons are still central to strategic planning is increased by reports of intentions to develop
new nuclear weapons or alter their design for new uses. Even the affirmation that only
concepts are being studied is not reassuring.”

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CRS-26
nuclear test moratorium, though it has asserted it would test if required.56 That has
not been needed because DOD has no requirement for nuclear weapons with new or
modified capabilities, and because the Secretaries of Defense and Energy have been
able to certify the stockpile without testing.57 Because the Administration does not
support the Comprehensive Test Ban Treaty,58 it has not spelled out arguments
against testing. It could be, however, that part of the rationale for avoiding testing is
political, as testing could cause massive protests domestically and internationally.
Further, most nations would likely view resumed U.S. testing as a clear breach of
U.S. obligations on behalf of nuclear disarmament and could lead to the unraveling
of the nuclear nonproliferation regime and to testing by others.
NNSA argues that RRW would reduce the need for testing. Linton Brooks said,
“not only is the reliable replacement warhead program not designed to foster a return
to nuclear testing, it is probably our best hedge against the need sometime in the
future to be faced with the question of a return.”59 Components could be designed
to be less sensitive to minor changes in materials and processes and to permit looser
tolerances. As a result, uncertainties that might prompt a nuclear test on current
weapons might be acceptable with RRW components.
Skeptics endorse a continuation of the nuclear test moratorium, but fear that
changes under RRW that NNSA claims would reduce the need for testing could
actually increase it. Small changes to the NEP that were within the parameters
validated by past nuclear tests could be done under LEP. It is as yet unclear if
changes made under RRW would be within these parameters; changes of greater
magnitude could undermine confidence in the warhead and lead to testing.
Might RRW Enable an Increase In Inherent Warhead Security? There
are two aspects to warhead security — access control and use control. The first is a
matter of physical protection and is the responsibility of DOD or DOE. The second
is ensuring that anyone who gains unauthorized access to a warhead is not able to
detonate it. In the wake of the 9/11 attacks, both have increased in importance. For
example, NNSA’s FY2002 request for Safeguards and Security was $448.9 million,
while the FY2006 request is $708.5 million. Use control has always been part of
warhead design. In the earliest days, fissile materials were reportedly kept separate
56 Linton Brooks testified, “we believe the nation must be prepared to carry out an
underground nuclear test in the event of unforeseen problems that can’t be resolved by other
means.” U.S. Congress. House. Committee on Armed Services. Strategic Forces
Subcommittee. Hearing on the FY2006 budget request from the Department of Energy on
Atomic Energy Defense Activities, March 2, 2005.
57 Senate Armed Services Committee hearing, Strategic Forces/Nuclear Weapons, April 4,
2005.
58 The treaty would ban nuclear explosions. It was opened for signature in 1996 but has not
entered into force. The U.S. Senate rejected it in 1999. See U.S. Congress. Congressional
Research Service. Nuclear Weapons: Comprehensive Test Ban Treaty. CRS Issue Brief
IB92099, by Jonathan Medalia. Updated periodically.
59 Senate Armed Services Committee hearing, Strategic Forces/Nuclear Weapons, April 4,
2005

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from bomb casings, in part for control.60 For many years, weapons have used
permissive action links, which require a code to activate the weapon. Now, with a
higher threat of terrorist attack, RRW supporters claim that further modifications to
the weapon for use control are in order. Linton Brooks, discussing RRW, stated:
We now must consider the distinct possibility of well-armed and competent
terrorist suicide teams seeking to gain access to a warhead in order to detonate
it in place. This has driven our site security posture from one of “containment
and recovery” of stolen warheads to one of “denial of any access” to warheads.
This change has dramatically increased security costs for “gates, guns, guards”
at our nuclear weapons sites. If we were designing the stockpile today, we would
apply new technologies and approaches to warhead-level use control as a means
to reduce physical security costs.61
Skeptics say that physical security and existing use-control features are quite
sufficient to protect warheads against theft by terrorists. The record in this regard is
exceptional. Warhead vulnerability has been reduced since the end of the Cold War
by withdrawing thousands of tactical nuclear weapons from Europe and from Navy
ships, and by reducing the number of deployed strategic nuclear warheads sharply.
General James Cartwright, USMC, Commander, U.S. Strategic Command, said, “I
am comfortable that we have the [nuclear] weapons protected and that we are moving
to a posture that will improve that protection in light of the changing threat.”62
Skeptics also question if DOE and DOD would reduce physical security even if
enhanced-security warheads were deployed. At any rate, in this view, Russian
nuclear warheads and materials are at much higher risk, so U.S. programs to secure
them would be a better investment than improvements to U.S. warheads.
Skeptics question the merits of redesigning warheads to incorporate new use-
control features. So doing might reduce confidence in the warheads, at high cost, and
for little potential benefit. According to Robert Peurifoy, a former Vice President at
Sandia National Laboratories, “Use control features were originally intended to delay
the unauthorized use of a nuclear weapon by friendly forces, including U.S.
custodians. It has now magically transformed in the minds of many to the prevention
of unauthorized use by terrorists. I don’t believe this can be done.”63
Might RRW Enable an Increase In Warhead Safety? While the United
States has taken steps to increase the safety of its warheads against lightning, fire,
impact, etc., not all warhead types incorporate all existing safety features. Some use
conventional high explosive (CHE) rather than insensitive high explosive (IHE); the
latter will not detonate in various accidents, while the former can, possibly scattering
60 Thomas Cochran, William Arkin, and Milton Hoenig, Nuclear Weapons Databook,
Volume I, U.S. Nuclear Forces and Capabilities, Cambridge, MA, Ballinger, 1984, p. 6. See
also ibid., pp. 30-31.
61 Brooks statement to Senate Armed Services Committee, April 4, 2005, p. 4.
62 Testimony at Senate Armed Services Committee hearing, Strategic Forces/Nuclear
Weapons, April 4, 2005.
63 Email from Robert Peurifoy to the author, March 26, 2005.

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plutonium. Some warheads lack fire-resistant pits, which are designed to increase
the time and temperature that a warhead exposed to fire will contain plutonium.
RRW advocates make the following argument. The technology of current
warheads is frozen in the 1980s, and LEP perpetuates that technology. The only way
to move beyond it is to use new-design components that incorporate current
advances. Since the United States will retain its stockpile for an indefinite time, the
cost of the safety gains would be amortized over many years. To enhance safety, the
RRW program may consider ways to modify warhead components, including those
in the NEP, to increase fire resistance.
Skeptics believe that warheads are quite safe, and that safety has improved over
the years thanks to safer designs and improved handling procedures. They are
concerned that some safety changes to the NEP would go beyond what is supported
by nuclear test data and could jeopardize reliability. For example, it is critically
important to the performance of the primary, and thus of the secondary, that the pit
implode with reasonable symmetry. A vast amount of effort has gone into
developing such pits and determining the bounds of “reasonable.” Because IHE is
significantly less energetic than CHE, more IHE must be used to obtain the same
implosive force. But using a larger amount of less energetic material would alter the
implosion wave, necessitating other adjustments in order to use the same pit.
Some safety-related changes would, skeptics believe, offer little value. For
example, the W88 or W76 warheads for Trident missiles could be candidates for
backfitting with IHE. They use CHE because the Navy sought to maximize yield-to-
weight. Using IHE on the W88 would have reduced range by 10 percent, or warhead
yield by “a modest amount,” or the number of warheads the missile could carry from
eight to seven.64 A 1990 study expressed concern about the safety of CHE.65 Sidney
Drell, the panel chairman and lead author of the study, however, stated in 2005 that
further studies revealed that the CHE in the W88 would not detonate even if
subjected to a harder knock than was realized in 1990, and that little would be gained
by substituting IHE in the warhead because the missile itself used a very energetic
propellant that is relatively easy to detonate. An accident that caused the propellant
to detonate could break apart the warheads, scattering plutonium, regardless of the
explosive used on the warhead. Unless the missile was redesigned to use a less
energetic propellant, which would be very costly, replacing CHE with IHE in the
warheads would produce little gain in safety. Further, because CHE and IHE are very
different in terms of energy density, burn characteristics, etc., Drell believes that
there is no way that IHE could be substituted for CHE without nuclear testing.66
Might RRW Reduce Adverse Consequences of Aging? RRW
supporters hold that the effects of aging can be reduced. Materials less sensitive to
64 U.S. Congress. House. Committee on Armed Services. Report of the Panel on Nuclear
Weapons Safety. Committee Print No. 14, 101st Congress, 2nd Session, p. 28. By Sidney
Drell, Chairman, John Foster, Jr., and Charles Townes.
65 Ibid., p. 32.
66 Information provided by Sidney Drell to the author, March 16, May 3, and May 4, 2005.

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aging can be used, processes can be better characterized so that they can be repeated
more precisely, and new components can be designed to use such materials and
processes.
Skeptics feel that RRW advocates have overstated the problem and minimized
the ability of LEP to cope with it. They feel that LEP can continue to correct aging
problems, as it has for many years. They hold that changes in materials must be done
with extensive study to determine if the material will work as did the original, but
assert that distinguishing the “large” changes of RRW from the “small” changes
made under LEP is largely a matter of semantics as long as the changes are made
under the condition that they will not require the resumption of nuclear testing.
Might RRW Enable Reduced Use of Hazardous Materials? Warheads
and their manufacture use many hazardous materials (hazmat). Hazmat require
special handling of materials and equipment: glove boxes, other layers of
containment, filtration of air vented into the atmosphere, disposition of scrap material
and contaminated solvents, and compliance with numerous environmental and safety
regulations. Regulations now ban some industrial solvents that were used to produce
current warheads. Minimizing or eliminating hazmat would produce benefits for
cost, ease of production, and worker safety. During the Cold War, warheads used
these materials to save weight, or because a particular material was the standard way
to solve a design problem. RRW advocates believe that advances in weapons
knowledge over the past quarter-century and establishing hazmat reduction as a
design goal make it possible to design components that minimize hazmat usage.
Skeptics agree that reduction of hazmat is a worthy objective, but question if it
is worth the costs and risks. Redesign, validation, and production of components
would require extensive testing and study, and would run the risk that a different
material, especially in the NEP, could impair reliability. New materials might impair
reliability if they decomposed in an unanticipated manner. Existing components and
materials have become increasingly well characterized. That knowledge base reduces
the advantage of eliminating hazmat. Some skeptics would retain existing
components, materials, and processes to the extent possible, even if that meant
retaining hazmat, on grounds that that is the surest way to retain confidence in
reliability. They would consider having dedicated production lines if needed to
produce some materials, and would consider filing for waivers to hazmat regulations
if needed to continue using such materials. Others would consider redesign of some
non-NEP components to eliminate hazmat if it could clearly be demonstrated, on a
case by case basis, that the benefits were substantial and the uncertainties were
minimal.
Policy Options for Congress
RRW is a new program with no specific, tangible product yet defined. In
deciding how to proceed on RRW, Congress has a number of options available to it.
Decide Whether and How to Proceed. As with any program, Congress
could choose to continue RRW as requested or terminate it. Several options exist

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between those extremes. Congress could allow NNSA to pursue RRW and LEP as
complementary programs. It could limit RRW to modification of components and
bar the program from considering new-design warheads. It could bar RRW from
making warhead changes that would increase military capability or that could
reasonably be expected to lead to nuclear testing. It could delay a decision on such
choices pending the outcome of the FY2005-FY2006 RRW study.
Clarify the Scope of RRW. Because RRW is a new program, its scope is in
the process of being defined. Congress might wish to help focus and shape the
program by asking NNSA to answer a number of questions to better define it.
! What design changes does NNSA envision making in warhead
components with RRW that could not be made with LEP?
! If NNSA proceeds with LEPs for W76 and W80, would that truly
preclude transformation of the nuclear weapons complex for
decades? If so, when must a choice between LEP and RRW be
made?
! Will RRW involve the construction of one or more new sites for the
nuclear weapons complex outside existing sites? Will it involve
construction of new facilities at existing sites? What upgrades to
facilities are envisioned to foster a responsive infrastructure?
! Will RRW lead to the closing of any existing nuclear weapons
complex sites?
Impose Legislative Requirements. Congress may also wish to define the
bounds of RRW legislatively by requiring that
! RRW components stay within the design parameters validated by
nuclear testing.
! RRW not be used to enhance military capabilities or provide for new
military missions.
! The number of non-deployed warheads be significantly reduced if
RRW proceeds.
Require a Plan and Budget for RRW. It may be too early to expect NNSA
to provide a detailed program plan and a rough budget estimate for the FY2006
budget cycle because RRW did not exist as a funded program until December 2004.
Congress may, however, wish to require NNSA to provide a five-year budget and
plan with its FY2007 budget submission.

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Appendix: Nuclear Weapons and the Nuclear
Weapons Complex
This report refers to nuclear weapons design, operation, and production
throughout. This Appendix describes key terms, concepts, and facilities as an aid to
readers not familiar with them.
Current strategic (long-range) and most tactical nuclear weapons are of a two-
stage design.67 The first stage, the “primary,” is an atomic bomb similar in concept
to the bomb dropped on Nagasaki. It provides the energy needed to trigger the
second stage, or “secondary.”
The primary has a hollow core, often called a “pit,” made of fissile plutonium
(isotope number 239). It is surrounded by a layer of chemical explosive designed to
generate a symmetrical inward-moving (implosion) shock front. A system injects
“boost gas” — a mixture of deuterium and tritium (isotopes of hydrogen) gases —
into the pit, and there is a neutron generator. When the explosive is detonated, the
implosion compresses the plutonium, greatly increasing its density and causing it to
become supercritical, so that it creates a runaway nuclear chain reaction. Neutrons
drive this reaction by causing plutonium atoms to fission, releasing more neutrons.
But the chain reaction can last only the briefest moment before the force of the
nuclear explosion drives the plutonium outward so that it can no longer support a
chain reaction. To increase the fraction of plutonium that is fissioned — boosting the
yield of the primary — the neutron generator injects neutrons directly into the
fissioning plutonium. In addition, intense heat and pressure cause the deuterium-
tritium mixture to undergo fusion. While the fusion reaction generates energy, its
purpose is to generate a great many neutrons. A metal “radiation case” then channels
the energy of the primary to the secondary.
The secondary contains lithium deuteride and other materials. The energy from
the primary implodes the secondary, causing fusion reactions that release most of the
energy of a nuclear explosion.
The primary, radiation case, and secondary comprise the “nuclear explosive
package.” Thousands of other “nonnuclear” components, however, are needed to
create a weapon. These include a case for the bomb or warhead, an arming, firing,
and fuzing system, use-control devices, and more.
Nuclear weapons were designed, tested, and manufactured by the nuclear
weapons complex, which is composed of eight government-owned contractor-
operated sites as well as the federal agency, the National Nuclear Security
Administration (a part of the Department of Energy) that manages the nuclear
weapons program. The sites include the Los Alamos National Laboratory (NM) and
Lawrence Livermore National Laboratory (CA), which design nuclear explosive
67 U.S. Department of Energy. Final Programmatic Environmental Impact Statement for
Stockpile Stewardship and Management, DOE/EIS-0236, September 1996, summary
volume, p. S-4. This page contains further information on nuclear weapon design and
operation.

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packages; Sandia National Laboratories (NM and CA), which design the nonnuclear
components that turn the nuclear explosive package into a weapon; Y-12 Plant (TN),
which produces uranium components and secondaries; Kansas City Plant (MO),
which produces many of the nonnuclear components; Savannah River Site (SC),
which processes tritium from stockpiled weapons to remove decay products; Pantex
Plant (TX), which assembles and disassembles nuclear weapons; and the Nevada
Test Site, which used to conduct nuclear tests but now conducts other weapons-
related experiments that do not produce a nuclear yield. These sites are now involved
in disassembly, inspection, and refurbishment of existing nuclear weapons.
Pit production is the most controversial aspect of nuclear weapons production,
and the one most closely linked to RRW. Rocky Flats Plant (CO) used to produce
pits, but that work was halted in 1989 due to safety concerns. Since then, the United
States has not made any pits that have been certified for use in stockpiled warheads
— and has therefore been unable to make entire new warheads (excepting for a small
number built shortly after Rocky Flats closed using pits that that plant had made).
Los Alamos has established a small-scale pit production plant at its plutonium
building, Plutonium Facility-4 (PF-4). PF-4 has produced several pits, but Los
Alamos has not completed the work needed to certify them for use in the stockpile.
NNSA anticipates that that work will be completed in FY2007, and that PF-4 will
achieve a capacity of 10 pits per year beginning in FY2007. Los Alamos further
believes that it would be difficult to expand PF-4’s capacity enough to support the
stockpile, though others challenge that view, arguing that if pit lifetime proves longer
than anticipated, or if the future stockpile declines more than anticipated, a smaller
capacity of an expanded PF-4 would suffice.
NNSA’s proposed solution is to build a new Modern Pit Facility (MPF), with
a capacity of 125 pits per year, to be operational beginning around 2021.68 RRW
might enable greater capacity at PF-4 or MPF by simplifying components and making
manufacturing processes more efficient. Increased capacity at PF-4 might enable that
facility to substitute for MPF, if pit requirements drop sharply, or to serve as a
backup to MPF so as to avoid the disruption to nuclear weapons production that
occurred with the shutdown of Rocky Flats Plant. Either of these options would
require a capacity at PF-4 several times larger than the 10 pits per year currently
projected for it.
68 Information provided by NNSA, May 10, 2005.

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