Order Code RL33748
Nuclear Warheads: The Reliable Replacement
Warhead Program and the Life Extension Program
Updated April 4, 2007
Jonathan Medalia
Specialist in National Defense
Foreign Affairs, Defense, and Trade Division

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Nuclear Warheads: The Reliable Replacement
Warhead Program and the Life Extension Program
Summary
Current U.S. nuclear warheads were deployed during the Cold War. The
National Nuclear Security Administration (NNSA) maintains them with a Life
Extension Program (LEP). NNSA questions if LEP can maintain them indefinitely
on grounds that an accretion of minor changes introduced in replacement components
will inevitably reduce confidence in warhead safety and reliability over the long term.
Congress mandated the Reliable Replacement Warhead (RRW) program in
2004 “to improve the reliability, longevity, and certifiability of existing weapons and
their components.” Since then, Congress has specified more goals for the program,
such as increasing safety, reducing the need for nuclear testing, designing for ease of
manufacture, and reducing cost. RRW has become the principal program for
designing new warheads to replace current ones.
The program’s first step is a design competition. The winning design was
selected in March 2007. If the program continues, NNSA would advance the design,
assess technical feasibility, and estimate cost and schedule in FY2008; start
engineering development by FY2010; and produce the first deployable RRW in
FY2012. Each year, Congress would decide whether to fund the program as
requested, modify it, or cancel it, and whether to continue or halt LEP.
RRW’s supporters argue that the competing designs meet all goals set by
Congress. For example, they claim that certain design features will provide high
confidence, without nuclear testing, that RRWs will work. Some critics respond that
LEP should work indefinitely and question if RRW will succeed. They hold that
LEP meets almost all goals set by Congress, and point to other LEP advantages.
Others maintain that the scientific tools used to create RRW designs have not been
directly validated by nuclear tests, and that the accretion of changes resulting from
LEP makes the link of current warheads to the original tested designs increasingly
tenuous. In this view, nuclear testing offers the only way to maintain confidence in
the stockpile. RRW raises other issues for Congress: Is RRW likely to cost more or
less than LEP? How much safety, and how much protection against unauthorized
use, are enough? Should the nuclear weapons complex be reconfigured to support
RRW? And what information does Congress need to choose among the alternatives?
This report is intended for Members and staff interested in U.S. nuclear weapon
programs. It will be updated occasionally. See CRS Report RL32929, The Reliable
Replacement Warhead Program: Background and Current Developments, by
Jonathan Medalia, for background and for tracking legislation and developments
related to RRW.

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Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Relationship among Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Terminology and Pending Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Meeting Congressional Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Warhead Characteristics: Reduced Need for Nuclear Testing . . . . . . . . . . . 7
1. Maintain high warhead reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2. Increase performance margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Stay within the design parameters validated by past
nuclear tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Design warheads for ease of certification without
nuclear testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Warhead Characteristics: Safety and Use Control . . . . . . . . . . . . . . . . . . . 13
5. Increase the ability of warheads to prevent unintended
nuclear detonation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. Increase the ability of warheads to prevent unauthorized
nuclear detonation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Reduce the consequences of an accident or attempted
unauthorized use that does not produce nuclear yield . . . . . . . . . 15
Warhead Characteristics: Design for Manufacturing and Maintenance . . . 16
8. Reduce the environmental burden imposed by warhead
production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
9. Design warheads for safety of manufacture . . . . . . . . . . . . . . . . . . 17
10. Design warheads for ease of manufacture . . . . . . . . . . . . . . . . . . 19
11. Design warheads for ease of maintenance . . . . . . . . . . . . . . . . . . 20
12. Increase warhead longevity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Stockpile Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
13. Fulfill current mission requirements of the existing stockpile . . . 22
14. Avoid requirements for new missions or new weapons . . . . . . . . 22
15. Focus initial efforts on replacement warheads for
submarine-launched ballistic missiles (SLBMs) . . . . . . . . . . . . . 22
16. Complement or replace LEP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
17. Reduce the number of nondeployed warheads . . . . . . . . . . . . . . . 24
Nuclear Weapons Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
18. Support upgrading of Complex capabilities . . . . . . . . . . . . . . . . . 25
19. Exercise skills of the Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
20. Reduce life cycle cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

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Issues for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
How much is enough? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Will the Department of Defense accept RRWs? . . . . . . . . . . . . . . . . . 31
Will LEP or RRW better maintain warheads for the long term
without nuclear testing, or is a return to testing required? . . . . . . 32
Might there be gaps between current RRW designs and
actual RRWs? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
How do pit issues bear on the choice between RRW and LEP? . . . . . 32
Risks of RRW vs. Risks of LEP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
What actions might the 110th Congress take? . . . . . . . . . . . . . . . . . . . 36
Appendix A. Nuclear Weapons, Nuclear Weapons Complex, and
Stockpile Stewardship Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Appendix B. Congressional Language Setting Goals . . . . . . . . . . . . . . . . . . . . . 40
Appendix C. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

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Nuclear Warheads: The Reliable
Replacement Warhead Program and the
Life Extension Program
Introduction
Nuclear weapons will continue to play a key role in U.S. security policy for
many decades. Yet the Department of Defense (DOD) and the National Nuclear
Security Administration (NNSA), the Department of Energy (DOE) agency in charge
of the nuclear weapons program, have raised concerns that maintaining current
weapons, which date from the Cold War, will become increasingly difficult.
At issue for Congress is how best to maintain the nuclear stockpile so that it will
retain, for many decades, capabilities that political and military leaders deem
necessary. There are three main options: (1) extend the service lives of current
warheads without nuclear testing; (2) develop, build, and deploy a new generation of
warheads without testing to replace the current stockpile; or (3) resume nuclear
testing, which the United States suspended in 1992, as a tool to help maintain
existing warheads or develop new ones.
This report focuses on the first two options. It compares how they respond to
congressional goals, presenting pros, cons, uncertainties, costs, and potential risks
and benefits, then discusses issues for Congress. Regarding the third option, the
United States has not conducted a nuclear test since 1992, yet has assessed for the
past 11 years that current warheads are safe and reliable. The Administration and
many in Congress prefer not to resume nuclear testing, so this report does not
consider it as a separate option, but discusses it at various points because testing
would provide additional data to help maintain or develop nuclear weapons. This
report does not consider a fourth option, abolition of U.S. nuclear weapons, as it has
garnered no support in Congress or the Administration.
Background
Almost all warheads in the current stockpile were built in the 1970s and 1980s.
They require ongoing surveillance and maintenance because their components
deteriorate. In the wake of the nuclear test moratorium that the United States has
observed since 1992, Congress instituted the Stockpile Stewardship Program (SSP)
in 1993 “to ensure the preservation of the core intellectual and technical

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competencies of the United States in nuclear weapons.”1 SSP has provided the
technical basis for advancing the relevant science in an effort to maintain confidence
in U.S. warheads without nuclear testing. NNSA requests $6,511.3 million for SSP,
under the heading “Weapons Activities,” for FY2008.2 Part of SSP is the Life
Extension Program (LEP), which seeks to maintain warheads by replacing certain
components, as needed, with newly-fabricated ones that stay as close as possible to
the originals; other components may be modified.
NNSA is concerned that it will become increasingly difficult to maintain high
confidence in current warheads for the long term with LEP. Reflecting this concern,
Congress initiated the Reliable Replacement Warhead (RRW) program in the
FY2005 Consolidated Appropriations Act (P.L. 108-447) “to improve the reliability,
longevity, and certifiability of existing weapons and their components.”
NNSA executes the RRW program in cooperation with DOD, the “customer”
for nuclear weapons, through the Nuclear Weapons Council, a joint DOD-NNSA
organization that oversees and coordinates nuclear weapon activities. When DOD
needs a new warhead, or when NNSA must modify a warhead, the council
establishes a warhead Project Officers Group (POG) to develop draft “military
characteristics” that the warhead must meet, such as explosive yield. The RRW POG
has representatives from key stakeholders: Office of the Secretary of Defense,
NNSA, U.S. Strategic Command, Navy, Air Force, and design teams. It spelled out
military characteristics for RRW and established RRW program priorities that the
council has vetted. Safety is the first priority; security/use control is the second.
Others — certifiability, cost, longevity, manufacturability, reliability, survivability
in nuclear environments, and yield — are not rank-ordered.3
NNSA must also meet policy goals in designing or maintaining warheads.
Congress, mainly through FY2006 legislation and committee reports, spelled out at
least 20 goals for RRW in the following categories: reduce the need for nuclear
testing; improve safety and use control; design for manufacturing and maintenance;
fulfill current mission requirements but not new ones; facilitate upgrading the nuclear
weapons complex (the “Complex”; see Appendix A); and reduce the cost of the
stockpile and Complex. RRW designs seek to meet all these goals.
The Nuclear Weapons Council started a competition between a New Mexico
(NM) design team composed of Los Alamos National Laboratory (LANL) (NM) and
Sandia National Laboratories’ NM site, and a California (CA) team of Lawrence
Livermore National Laboratory (LLNL) (CA) and Sandia’s CA site. Both teams
created preliminary warhead designs between October 2005 and March 2006, then
did further detailed design work. According to a December 1, 2006, statement, the
Nuclear Weapons Council has determined that RRW is a feasible strategy for
1 P.L. 103-160, FY1994 National Defense Authorization Act, Section 3138(a).
2 U.S. Department of Energy. Office of Chief Financial Officer. FY 2008 Congressional
Budget Request. Vol. 1, National Nuclear Security Administration. DOE/CF-014, Feb. 2007,
p. 3, at [http://www.mbe.doe.gov/budget/08budget/Content/Volumes/Vol_1_NNSA.pdf].
3 Information provided by Dr. Barry Hannah, SES, Chairman of the RRW POG and Branch
Head, Reentry Systems, Strategic Systems Program, U.S. Navy, Oct. 31, 2006.

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CRS-3
sustaining U.S. nuclear weapons without testing.4 It selected the California design
in March 2007.5 NNSA requests FY2008 funds to prepare a detailed design, assess
technical feasibility, and develop an estimate of cost and schedule. NNSA plans to
conduct engineering development of the selected design beginning by the start of
FY2010. The FY2007 National Defense Authorization Act (P.L. 109-364, Section
3111) sets as an objective having the first production unit (FPU, the first complete
warhead from a production line certified for deployment) of RRW in 2012, and the
FPU is scheduled for September 2012. NNSA stated in April 2007 that a 2012 FPU
remains its target date. There is some uncertainty about NNSA’s ability to meet that
date. Barry Hannah, Chairman of the RRW POG, stated, “I believe that an FPU of
FY2012 for the first RRW is extremely optimistic.”6 Each year, it would be up to
Congress to decide whether to fund the program as requested, modify it, or cancel it.
Relationship among Goals
Many goals Congress set for RRW are interrelated. A more efficient Complex
and increased confidence in long-term reliability might let DOD retain fewer
nondeployed warheads as a hedge against reliability problems or adverse geopolitical
changes. Wider performance margins would give DOD more confidence in NNSA’s
ability to certify warheads without testing. The effort to design and produce an RRW
that offers greater resistance to unauthorized use, that is easier to manufacture, and
that increases performance margins should help maintain design and production
expertise. Using more environmentally benign materials should increase safety and
ease of manufacture and facilitate a smaller and more modern Complex.
Many goals seek to reduce cost over the long term. Reducing the use of
hazardous materials requires less equipment to shield workers and protect the
environment, permits some work to be done outside of high-cost buildings, and
reduces waste streams. Moving some work outside of high-cost buildings to make
space available inside them may permit more production lines to be installed in such
buildings, increasing their productivity. Designing warheads for ease of manufacture,
assembly, and maintenance is likely to save money by requiring fewer process steps,
reducing the equipment and workers to support those steps, and permitting more
rapid production. Less rigid tolerances and wider design margins reduce costs by
reducing the number of rejected components, increasing throughput, and reducing
waste streams. Making a warhead more resistant to terrorist attack could slow the
growth of physical security costs.
While Congress has specified many goals, it did not set a clear goal on an issue
that it has considered for other nuclear weapons: whether RRW is to be a “new
warhead.” Congressional language on this point may appear ambiguous. For
4 U.S. Department of Energy. National Nuclear Security Administration. “Nuclear Weapons
Officials Agree to Pursue RRW Strategy,” press release, Dec. 1, 2006.
5 U.S. Department of Energy. National Nuclear Security Administration. “Design Selected
for Reliable Replacement Warhead.” Press release, March 2, 2007.
6 Information provided by Dr. Barry Hannah, SES, Branch Head, Reentry Systems, Strategic
Systems Program, U.S. Navy, telephone conversation with the author, Oct. 23, 2006.

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CRS-4
example, the program is “to improve the reliability, longevity, and certifiability of
existing weapons and their components”;7 a goal is “to develop replacement
components for nuclear warheads”;8 another goal is “[t]o ensure that the nuclear
weapons infrastructure can respond to unforeseen problems, to include the ability to
produce replacement warheads”;9 “any new weapon design must stay within the
design parameters validated by past nuclear tests”;10 and a committee’s “qualified
endorsement of the RRW initiative is based on the assumption that a replacement
weapon will be designed only as a re-engineered and remanufactured warhead for an
existing weapon system in the stockpile.”11
Part of the ambiguity is semantic. “Warhead” refers clearly to a nuclear
explosive device, but “weapon” may mean a warhead or its delivery system. If
“weapon” refers to delivery system, then the warhead may be viewed as a
“component” of the delivery system. If “weapon” refers to “warhead,” then a
component would be a part of a warhead. The term “new” is also ambiguous. While
neither competing RRW design is exactly like any warhead currently deployed, each
design contains key components that are similar to those of current warheads.
Whatever the case, NNSA could not meet the goals for RRW by modifying
current warheads. A dominant design consideration of these Cold War warheads
was maximizing yield to weight — having the most explosive energy possible within
a tight weight budget so that more warheads could be placed on a missile. To pare
down weight, some warheads used a nuclear explosive package (NEP; see Appendix
A) designed with parameters close to the point at which the warhead would fail to
meet its design requirements. NNSA expresses concern about the impact of even
minor changes to NEP components that the Life Extension Program might introduce.
These tight designs could not undergo drastic modifications needed to accommodate
such goals as increased safety and use control, lower cost, and reduced use of
hazardous materials and still provide confidence that they would work as intended.
7 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, 108th Cong., 2nd sess.,
H.Rept. 108-792, 2004, p. 951.
8 U.S. Congress. Senate. Committee on Armed Services. National Defense Authorization Act
for Fiscal Year 2006. S.Rept. 109-69 to accompany S. 1042, 109th Cong., 1st sess., 2005, p.
482.
9 P.L. 109-163, FY2006 National Defense Authorization Act, Section 3111.
10 U.S. Congress. Committee of Conference. Making Appropriations for Energy and Water
Development for the Fiscal Year Ending September 30, 2006, and for Other Purposes.
H.Rept. 109-275 to accompany H.R. 2419, 109th Cong., 1st sess., 2005, p. 159.
11 U.S. Congress. House. Committee on Appropriations. Energy and Water Development
Appropriations Bill, 2006. H.Rept. 109-86 to accompany H.R. 2419, 109th Cong., 1st sess.,
2005, p. 130.

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CRS-5
Terminology and Pending Studies
This report refers to “supporters” and “critics” of RRW. While this division
may oversimplify matters, it permits the report to highlight key points of contention
while avoiding a tedious discussion of minor differences. In general, supporters of
LEP are critics of RRW, and vice versa, but finer divisions of opinion exist.
Raymond Jeanloz, Professor of Earth and Planetary Science at the University of
California at Berkeley and a long-time adviser to the U.S. government on technical
aspects of national and international security, said, “I still don’t think of myself as
being in the ‘critic’ [of RRW] category because I find that many of the objectives
motivating [RRW] are reasonable, and it’s more in the implementation (and
interpretation of what is needed) where I find myself concerned.”12 Some RRW
supporters question aspects of RRW designs. And supporters of RRW are not
necessarily critics of LEP. As Los Alamos states,
We have been asked to study the feasibility of RRW-design enabled by relaxing
yield/weight. We have found compelling designs that provide added margin,
surety, and manufacturability in our studies. Just because this exercise has been
successful does not imply that we’re opponents of LEP-strategies. At the end of
the day, we are service providers and advisors. We will pursue the course of
action decided by the Administration, Congress, and the DoD. If they wish to
pursue LEPs, then we’re fully committed to that path and will provide our best
advice and service.13
This report offers two terminological notes. First, as the RRW program has
progressed and congressional goals for it have become clearer, the term “Reliable
Replacement Warhead” no longer seems appropriate. It implies that current warheads
are not reliable, which Ambassador Linton Brooks, the head of NNSA, has
emphatically denied.14 It implies that reliability is the program’s goal, yet Congress
has set forth dozens of goals. It deemphasizes “replacement,” yet a key goal of RRW
is to replace existing warheads in such a way as to be used on existing aeroshells15
and missiles. Second, this report distinguishes between “Competing Candidate RRW
Designs,” or CCRDs, which currently exist; the RRW program; and RRWs, actual
warheads that may be built in the future.
12 Personal correspondence, Sept. 7, 2006.
13 Information provided by Los Alamos National Laboratory, Sept. 20, 2006.
14 According to Brooks, “Stockpile Stewardship is working; the stockpile remains safe and
reliable.” “Statement of Ambassador Linton F. Brooks, Under Secretary for Nuclear
Security and Administrator, National Nuclear Security Administration, U.S. Department of
Energy, Before the Senate Armed Services Committee, Subcommittee on Strategic Forces,”
Mar. 7, 2006, p. 1 (original emphasis); at [http://armed-services.senate.gov/statemnt/
2006/March/Brooks%2003-07-06.pdf].
15 An aeroshell, generally called a reentry vehicle by the Air Force and a reentry body by the
Navy, is the cone-shaped shell that carries an individual warhead on a ballistic missile. It
protects the warhead against burnup as it reenters the atmosphere at high speed and
minimizes degradation of accuracy.

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CRS-6
Several external reviews of the program are forthcoming. The House
Appropriations Committee directed NNSA to have the JASONs, a group of scientists
who advise the government on defense matters, conduct an independent peer review
to evaluate the competing RRW designs. The JASONs should evaluate the RRW
design recommended by the POG [the RRW Project Officers Group] against the
requirements defined by congressional legislative actions to date and the
elements defined in the Department of Defense’s military characteristics for a
reliable replacement warhead requirements document. The JASON review
should also include an analysis on the feasibility of the fundamental premise of
the RRW initiative that a new nuclear warhead can be designed and produced
and certified for use and deployed as an operationally-deployed nuclear weapon
without undergoing an underground nuclear explosion test.16
The report was due March 31, 2007.17 The schedule for this report as decided by the
JASONs, NNSA, and the House Appropriations Committee calls for a preliminary
report to be submitted to NNSA by March 1, 2007, an executive summary of the final
report by August 1, 2007, and the final report by October 1, 2007.18 The preliminary
report, which is classified, was submitted in late January.19 A study by the Nuclear
Weapons Complex Assessment Committee of the American Association for the
Advancement of Science will examine whether RRW is the best path for addressing
certain potential risks of SSP and LEP and for developing a responsive infrastructure.
The committee presented an interim progress report in February 2007;20 the final
report might be completed in April 2007.21 A third report, mandated by the FY2006
National Defense Authorization Act, P.L. 109-163, Section 3111, is to discuss
RRW’s “feasibility and implementation.” It was due March 1, 2007. It will “discuss
the relationship of the Reliable Replacement Warhead program within the Stockpile
Stewardship Program and its impact on the current Stockpile Life Extension
Programs.” NNSA indicated in late March 2007 that this report may be delivered to
Congress in early April 2007.22
16 U.S. Congress. House. Committee on Appropriations. Energy and Water Development
Appropriations Bill, 2007, H.Rept. 109-474 to accompany H.R. 5427, 109th Cong., 2nd sess.,
2006, p. 110.
17 Ibid.
18 Information provided by Roy Schwitters, S.W. Richardson Foundation Regental Professor
of Physics, University of Texas at Austin, and Chair of the JASON Steering Committee,
email, Jan. 29, 2007.
19 Information provided by Professor Roy Schwitters, email, March 27, 2007.
20 American Association for the Advancement of Science. Center for Science, Technology
and Security Policy. Nuclear Weapons Complex Assessment Committee. C. Bruce Tarter,
Chair. “The United States Nuclear Weapons Program: The Role of the Reliable
Replacement Warhead.” Interim progress report, presented at American Association for the
Advancement of Science Meeting, February 18, 2007.
21 Personal communication by American Association for the Advancement of Science staff
with the author, March 26, 2007.
22 Personal communication by NNSA staff with the author, March 26, 2007.

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Meeting Congressional Goals
This report now discusses how the competing designs and LEP seek to meet
congressional goals and presents the debate by supporters of LEP, RRW, and others.
Some of these goals are taken directly from congressional language, while others are
derived from it. To help the reader link goals to congressional language, each goal
is followed by one or more numbers in brackets. These numbers refer to excerpts
from legislation (numbered 2) or committee reports (other numbers) in Appendix B.
Warhead Characteristics: Reduced Need for Nuclear Testing
In order to maximize yield to weight, warheads were designed close to points
at which they would fail, but nuclear testing helped provide sufficient confidence that
they could be placed in the stockpile. The United States has been able to maintain
its weapons despite the moratorium on nuclear testing largely because SSP has
developed or improved upon many means — such as nonnuclear experiments, large
and small experimental facilities, computer simulations, and new analyses of data
from past nuclear tests — to better understand warhead performance in order to
anticipate, identify, and fix warhead problems. As a result, the Secretaries of Defense
and Energy have made 11 annual assessments that each warhead type in the stockpile
remains safe and reliable, and that testing is not required.
Yet NNSA and its labs have expressed concerns that, over the long term, minor
changes to current warheads through repeated LEPs and maintenance will decrease
confidence in the warheads, possibly requiring a return to nuclear testing. Critics
counter that careful attention to minimizing changes, and advances in understanding
of the relevant science, should keep existing warheads reliable for many years.
Because of its desire to avoid testing, Congress has stated that a goal for RRW
is to minimize the need to return to testing. NNSA claims that the RRW program
will meet this goal because of steps, discussed below, to increase confidence. LEP’s
proponents respond that the lack of a nuclear test “pedigree” reduces confidence in
RRWs. Others maintain that certification using SSP has been a political assessment
rather than a technical one. Since SSP emerged after the moratorium on testing
began, this position holds that its tools were never validated with nuclear tests done
for that purpose, so they could lead to false conclusions. Accordingly, in this view,
NNSA will not know for sure if SSP, and thus RRW or LEP, work until it conducts
nuclear tests.23 As former LANL Director Siegfried Hecker stated in 1997,
Of course, if nuclear testing were allowed, we would gain greater confidence in
the new tools. We could validate these tools more readily, as well as validate
some of the new remanufacturing techniques. One to two tests per year would
serve such a function quite well. Yields of 10 kt would be sufficient in most
cases. Yields of 1 kt would be of substantial help.24
23 Information provided by Kathleen Bailey, former Assistant Director for Nuclear and
Weapons Control, U.S. Arms Control and Disarmament Agency, Nov. 28, 2006.
24 S.S. Hecker, “Answers to Senator Kyl’s questions,” in Senate Committee on
(continued...)

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CRS-8
1. Maintain high warhead reliability. [1, 2, 4, 6, 7]25 A Sandia report
defines reliability for a nuclear warhead as “[t]he probability of achieving the
specified yield, at the target, across the Stockpile-To-Target Sequence of
environments, throughout the weapon’s lifetime, assuming proper inputs.”26 In this
definition, the specified yield is generally understood to mean within ten percent; the
Stockpile-To-Target Sequence of environments is the range of conditions the
warhead is expected to experience in its service life in storage, transit, or use, such
as temperature extremes, radiation from any nuclear-armed missile defense
interceptors, and acceleration; lifetime is the “original lifetime objective as specified
at the time of design”; and proper inputs are arming, fuzing, and firing signals.
RRW’s designers have sought to obtain high reliability by maximizing margins
(building in more performance than is needed). The design teams argue that they
could do so because the designs were unconstrained by technologies and design
choices made decades ago. With wide margins, they claim, material deterioration or
design or manufacturing defects are less likely to degrade warhead performance
below the minimum required. Further, diagnostic systems that could be incorporated
in the designs would help detect deterioration at an early stage. In contrast, RRW
advocates project increasing difficulty in maintaining the reliability of existing
warheads. Sandia stated, “As systems age and [warhead] lives are extended, changes
due to aging or repair creep into the system that make it more difficult to predict
performance, and repair itself becomes more challenging as we move further away
from the design era.”27
LEP’s supporters argue that current warheads are reliable enough, as evidenced
by the 11 stockpile assessments. While problems emerge, solutions do as well, and
LEP supporters argue that SSP has been keeping at least even in this race. RRW
supporters agree with this latter statement; an NNSA official stated, “Each year, we
are gaining a more complete understanding of the complex physical processes
underlying the performance of our aging nuclear stockpile.”28
Some doubt that either LEP or RRW can be assessed as reliable. They contend
that stewardship tools should not be relied on, and that RRWs cannot be assessed as
reliable without testing because of questions about how new warheads will function.
They also contend that LEPs cannot be assessed as reliable without testing because
24 (...continued)
Governmental Affairs, Safety and Reliability of the U.S. Nuclear Deterrent, p. 83.
25 As noted, these numbers refer to excerpts from congressional language in Appendix B.
26 R.L. Bierbaum et al., “DOE Nuclear Weapon Reliability Definition: History, Description,
and Implementation,” Sandia National Laboratories, report SAND99-8240, April 1999, p.
8. Available at [http://www.wslfweb.org/docs/usg/reli99.pdf#search=%22doe%20nuclear%
20weapon%20reliability%20definition%22].
27 Information provided by Sandia National Laboratories (NM), Aug. 3, 2006.
28 “Statement of Thomas P. D’Agostino, Deputy Administrator for Defense Programs,
National Nuclear Security Administration, Before the House Armed Services Committee,
Subcommittee on Strategic Forces,” Apr. 5, 2006, p. 1.

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CRS-9
LEPs will inevitably introduce small changes into warheads, and their cumulative
effect will undermine confidence in reliability.29
2. Increase performance margins. [3, 7] Margins, uncertainty, and
confidence are important for understanding risks of implementing RRW or LEP
without nuclear testing. For a given characteristic, a minimum value is required for
a warhead to operate as intended. Margin is the amount by which the design
parameter exceeds that minimum — the excess performance built into the design.
A warhead’s design provides a higher value than the minimum for each characteristic
to ensure margin and avoid failure. Uncertainty results from imprecise knowledge
of design parameters and of the minimum value required to ensure performance. The
labs use computer models, experimental data, etc., to bound these uncertainties.
Confidence is the ratio of margin to uncertainty: if margin is high and uncertainties
low, confidence is high; if both are high, confidence is low. Having margins greater
than uncertainties provides confidence against potential failure modes.
The close relationship of margins, uncertainties, and confidence is formalized
in Quantification of Margins and Uncertainties, or QMU, an analytic framework that
LANL and LLNL have developed. They are implementing it to assess, in the absence
of testing, confidence in weapon performance. Since its inception, the nuclear
weapons program has used the core principle of QMU, building margins into
warhead designs, to assess performance risk, such as identifying situations where
small changes could cause performance to degrade sharply.
Current missile warheads maximize explosive yield while minimizing warhead
weight. For example, to minimize weight, a warhead’s primary stage (see Appendix
A) has little yield above that needed to make the warhead work as intended. While
this approach resulted in “thin” margins, nuclear testing helped provide confidence
that warheads would work. For RRW, DOD traded off a reduction in yield per unit
of weight to improve margin (as well as safety and use control). To gain confidence
without testing, both teams used metrics that were derived statistically from the
nuclear testing database but that can be obtained without nuclear testing, such as
through calculations or hydrodynamic experiments.30 Using existing nuclear test
data, the labs found that if these metrics exceed certain values, there is very high
confidence that the primary will work as intended. Knowing this, designers at both
labs adjusted CCRDs so that primary margins greatly exceed the minimum required.
The design teams claim a key advantage for the competing designs: because the
designs start fresh, designers can increase margin. The teams view added margin as
the single most important goal of the designs, as it enables confidence without testing
by compensating for unanticipated uncertainties. In contrast, they argue, one cannot
increase margin in an LEP in the many cases requiring changes to the warhead
because that would push the warhead beyond the design envelope validated by
29 Information provided by Robert Barker, former Assistant to the Secretary of Defense for
Atomic Energy, Nov. 29, 2006.
30 These experiments use powerful high-speed x-rays and other diagnostic equipment to
measure the geometry and density of a pit (made with surrogate material) as it implodes,
allowing experimental determination of key values independent of computer models.

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CRS-10
nuclear testing. As a result, they claim, one can only attempt to drive down
uncertainty, but that path has proven costly and might in some cases be unsuccessful.
RRW’s critics hold that SSP, the surveillance program, and LEP can maintain
margins through careful remanufacture of nuclear explosive package components to
minimize changes. They also state, to general agreement, that primary margin for
some warheads could be increased with no change to a warhead through revised
means of dealing with the boost gas.31 Critics express concern that RRWs would
increase uncertainty, offsetting the potential gain in margin that advocates claim for
RRW. Precisely because the design is new, critics believe RRWs are likely to have
“birth defects,” while such defects have been wrung out of existing designs. Critics
point to a 1996 Sandia study of stockpile surveillance that showed that the highest
number of problems requiring corrective action occurred in the first three years after
FPU, a lower but still substantial number of such findings occurred in years 4-11
after FPU, and very few occurred in years 12-23.32 (There are no public data on
whether that number remains low, or increases, after year 23 because the study has
not been updated.) RRW’s supporters respond that LEP can also introduce birth
defects.
3. Stay within the design parameters validated by past nuclear
tests. [2, 8] The two key issues for the functioning of a nuclear weapon are (1) does
the primary boost with enough energy to give its design yield, and (2) does enough
energy transfer from the explosion of the primary to drive the secondary successfully.
Nuclear testing used to provide data to make judgments on these issues. In addition
to improved margins, another basis for confidence in CCRDs is that while both teams
explored diverse potential designs, they ultimately stayed close to past experience.
In direct response to congressionally-mandated requirements, the NM team rejected
certain design concepts because they fell outside design parameters validated by prior
nuclear testing. Livermore states,
All RRW/CA components, or components very similar to the RRW/CA primary
and secondary have been nuclear tested. For example, the primary uses a tested
design with a modest and very well understood modification of the pit to
provide added margin. Thus there is direct nuclear test proof that the RRW/CA
31 Boost gas is a mixture of tritium and deuterium gases injected into the pit to increase its
explosive energy; see Appendix A. A study found, “Primary yield margins can be increased
by appropriate changes specific to each stockpile system. These include changes to initial
boost-gas composition, shorter boost-gas exchange intervals, or improved boost-gas storage
and delivery systems. These modifications have been validated by nuclear test data for the
appropriate systems, and they would not place burdens on the maintenance or deployment
of the systems by the military.” National Academy of Sciences, Committee on Technical
Issues Related to Ratification of the Comprehensive Nuclear Test Ban Treaty, Technical
Issues Related to the Comprehensive Nuclear Test Ban Treaty, Washington, National
Academy Press, 2002, p. 31. See also JASON report JSR-99-305, Primary Performance
Margins, McLean, VA, MITRE Corporation, 1999, p. 2. The Air Force and Navy would
need to weigh the advantages and disadvantages of any specific future changes of this sort.
32 Kent Johnson et al., Stockpile Surveillance: Past and Future, prepared by Lawrence
Livermore National Laboratory, Los Alamos National Laboratory, and Sandia National
Laboratories, Sandia Report SAND95-2751, UC-700, January 1996, p. 32.

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CRS-11
design will perform properly. In addition, the RRW/CA design draws on over
100 other nuclear tests to assure confidence in various materials, components,
and features in the design. In addition the RRW/CA team built on LEP and
Stockpile Stewardship to develop certification tools that boosted confidence in
its RRW design.33
LEP advocates hold that because existing warheads have undergone extensive
testing in the course of their development, they necessarily stay within design
parameters validated by such tests. Those who would resume testing reply to both
positions by noting that SSP, on which RRW depends, has not been validated by
nuclear testing, and that changes introduced by LEPs and by minor modifications
during maintenance move existing warheads away from validated design parameters.
4. Design warheads for ease of certification without nuclear
testing. [2, 6] A certification plan defines the scope of work required to certify a
warhead design to DOD. In the past, the laboratories developed warheads through
an iterative process of computation, small- to large-scale experiments, and nuclear
testing. That information provided grounds for issuing a Major Assembly Release34
for warheads at the end of their development. LEPs are also certified in the
development cycle, about three to six months before first production, using SSP
tools. The RRW design teams, applying lessons learned in certifying LEPs, began
the certification process and design together, forcing greater attention from the outset
to potential failure modes in order to increase confidence. The CA team states that
it “made basic design choices that ease certification without testing.”35 LANL states:
The NM design began with an exhaustive evaluation and statistical analysis of
nuclear test data that led to design choices made to improve the margin for key
primary and secondary performance parameters dramatically while avoiding
known failure modes. These choices insured that RRW would be firmly within
our nuclear test experience and provided robust performance even in the event
of unanticipated failure modes. The resulting high margin-to-uncertainty ratios
allow ready certification through our QMU (quantification of margins and
uncertainties) approach.36
In addition, the teams used various SSP tools, such as hydrodynamic facilities
(see note 23) to provide confidence that the warheads could withstand a diverse set
of accident scenarios and threats. According to LANL,
hydrodynamic testing provides confidence in certifying that, even with new
surety features, the design will function as intended. LANL fired its first
hydrodynamic shot in support of its design on September 6, 2006, and early data
33 Information provided by Lawrence Livermore National Laboratory, Sept. 19, 2006.
34 A Major Assembly Release is a statement from NNSA to DOD that a warhead (or major
component) will meet all military requirements with any exceptions noted.
35 Information provided by Lawrence Livermore National Laboratory, Sept. 19, 2006.
36 Information provided by Los Alamos National Laboratory, Oct. 24, 2006.

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CRS-12
analysis indicates that these features will perform as LANL’s weapons codes had
predicted.37
RRW supporters note that an LEP replaces defective or deteriorated components
with new ones. Unlike RRW, NEP components in an LEP must be as close as
possible to the originals, which often means using the original materials and
manufacturing processes. Certification of warheads that have undergone an LEP is
difficult, it is argued, because it involves certification that the current manufacturing
process duplicates the original process, which can generally be done closely but not
precisely. The RRW design, in contrast, starts with a new design that uses modern
manufacturing processes that have been selected in part for ease of certification.
RRW is an attempt to create a warhead that can be certified without testing.
Some outside experts question whether it can meet this standard as well as extending
the life of current warheads through LEP. According to one, the issue for RRW
has simply to do with retaining the same, or higher, confidence in our warheads’
performance if some of their parameters are altered from the values built into our
current arsenal, based on a long test pedigree, and whose performance over time
has been confirmed by the LEP surveillance/simulation/analysis programs. Can
we meet that challenge successfully? This is the question that has to be
addressed with careful analysis and independent scrutiny. We must determine
how great an interpolation - not extrapolation - can be made from current design
parameters, and how many parameters altered at the same time before we may
be deceiving ourselves. In the end, what will it take to convince a responsible
leader in the White House, or the Pentagon, or at [the U.S. Strategic Command],
to have confidence in such a new design without requiring new test data? This
and this alone is the standard that RRW must meet.
Another outside expert was more critical:
The present nuclear weapon stockpile contains 8 or so nuclear weapon types.
That population has enjoyed perhaps 100 successful yield tests. These weapons
have benefited from a test base of perhaps 1,000 yield tests conducted during the
40 or so years when nuclear testing was allowed. Is the DoD really willing to
replace tested devices with untested devices? Why are Livermore and Los
Alamos designing devices that can’t be yield-tested?38
Other critics argue that both RRW and LEP diverge from reality. They believe
that confidence in the U.S. nuclear arsenal — by the United States, its friends, and
its foes alike — is so central to U.S. security that we must conduct nuclear tests,
regardless of political concerns, because only testing can maintain confidence.39
Supporters of LEP and RRW respond that most nuclear tests used test devices that
37 Information provided by Los Alamos National Laboratory, Sept. 20, 2006.
38 Correspondence with Robert Peurifoy, former Vice President of Technical Support,
Sandia National Laboratories, Albuquerque, NM, Sept. 24, 2006.
39 Information provided by Kathleen Bailey, former Assistant Director for Nuclear and
Weapons Control, U.S. Arms Control and Disarmament Agency, Nov. 28, 2006.

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CRS-13
differed somewhat from deployed warheads, so the link between fielded warheads
and nuclear tests is more complex than it might appear.
Warhead Characteristics: Safety and Use Control
The design teams were asked to put as much safety and use control into their
designs as practical. Both designs have new features that do not appear in any
current warhead to counter various accident and attack scenarios. Lawrence
Livermore National Laboratory (LLNL) and Los Alamos National Laboratory
(LANL) have principal responsibility for the nuclear explosive package design,
which includes inherent safety. Sandia National Laboratories has principal
responsibility for the design of nonnuclear components, including those for use
control and safety; integration of these components into the warhead; and mechanical
and electrical interfaces between the warhead and the missile or bomber that carries
it. The three laboratories share responsibility for warhead features for disablement.
5. Increase the ability of warheads to prevent unintended nuclear
detonation. [2, 3, 4, 5, 7] While all stockpile weapons meet the safety
requirements specified by DOD, nuclear detonation safety cannot be assured in an
abnormal environment in which the nuclear safety design configuration is breached
(the weapon is broken open), the nuclear explosive package remains operable, and
energy capable of initiating a nuclear detonation is present. Warheads in the current
stockpile that do not have design features to guarantee that they will survive this so-
called “Trinity condition” without producing a nuclear yield must have a “Trinity
exception,” meaning that DOD accepts them into the stockpile with a specific
exception for that condition. Both RRW designs have certain features so that they
do not require a Trinity exception. One way the NM design meets the Trinity
condition is to use optical isolation, discussed under Goal 9.
LEP advocates see current warheads as safe enough. They view as farfetched
such scenarios as Trinity that are used to justify RRW on grounds of reducing the risk
of accidental detonation. Analysts can always develop scenarios in which a particular
new weapon makes an immense difference. But the existence of a scenario does not
require spending large sums to address it. Critics note that no U.S. warhead has ever
detonated accidentally. While dozens of accidents have involved nuclear weapons,
especially in the 1950s and 1960s, later warhead designs incorporated lessons
learned, arguably reducing risk to an extremely low level.
6. Increase the ability of warheads to prevent unauthorized nuclear
detonation. [2, 3, 4, 5, 7] Current weapon systems have use control features
designed to meet Cold War threats. These features permit authorized use of a
warhead in its intended mode of operation and deny unauthorized use. An example
of use control, incorporated into warheads for decades, is the permissive action link,
which requires insertion of a code to make the warhead work. More generally, use
control is the entire release system stretching from the President to the warhead.
The 9/11 attacks changed use control requirements dramatically. As
Ambassador Linton Brooks, the Administrator of NNSA, testified in 2005:

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CRS-14
During the Cold War, the main security threat to our nuclear forces was from
spies trying to steal our secrets. Today, the threat to classified material remains,
but to it has been added a post-9/11 terrorist threat that is difficult and costly to
counter. 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.40
In response to such concerns, the design teams were directed to incorporate the
maximum safety and use control practical, and both designs offer a “menu” of new
features to this end. LLNL states that the CA design provides an “unprecedented
level of use control” that is “beyond the best in stockpile.”41 LANL calls the NM
design “revolutionary” in this regard. In contrast, RRW advocates note, new use
control features could in general not be backfitted into current missile warheads
because their designs are so tight that they could not accommodate even minor
changes. (Gravity bombs are less constrained in weight because bombers can carry
much more payload than missiles.) At the same time, the new safety and use control
features add cost and manufacturing complexity, and have the potential to reduce
reliability by an amount the labs anticipate would be small. Some supporters
question whether all possible features warrant inclusion.
Enhanced use control is very important to the Air Force, especially because
ICBM warheads are more vulnerable outside of their silos. However, such features
would not lead the Air Force to reduce physical security. It would be impossible to
hide an operation that removes warheads from ICBMs and transports them back to
the base, so the Air Force would use a large security force as a show of force even
with RRWs. Enhanced use control features, though, would create more options for
security forces in dealing with an accident or an attack. Accordingly, the Air Force
would consider such features even though it expects that they would reduce reliability
by a small amount; at issue are the relative costs and benefits of such a tradeoff.
These features can be tested to see how they respond to different events, which can
provide confidence in their value. The Air Force does not expect these features to
affect field operations adversely, and the overall design of the RRW may make field
operations easier. At this point in the development cycle, it is too early for the Air
Force to know whether to recommend dropping any safety and use control features.42
40 “Statement of Ambassador Linton F. Brooks, Administrator, National Nuclear Security
Administration, U.S. Department of Energy, Before the Senate Armed Services Committee,
Subcommittee on Strategic Forces,” Apr. 4, 2005, p. 4.
41 “Key Points for RRW/CA,” briefing slide, Lawrence Livermore National Laboratory, c.
June 2006. An RB (reentry body) or RV (reentry vehicle) is an aeroshell, as described in
note 13.
42 Information provided by a senior Air Force official, interview with the author, Sept. 26,
2006.

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CRS-15
Some critics believe current warheads and external physical security measures
provide high use control, and question the need for more use control. There has never
been an unauthorized detonation of a U.S. warhead, and means to reduce this risk
have been introduced continually. Upgrading physical security or reducing the
number of weapon storage sites can improve use control. Not every threat hypothesis
requires a response: LEP’s supporters see the risk of terrorists penetrating a heavily-
guarded military base or DOE facility and detonating a nuclear weapon to be remote.
Some ask if part of the funds to improve U.S. warhead security might increase U.S.
security more if spent to secure Russian warheads and nuclear materials.43
Others feel that safety and use control must be increased as much as possible,
and would be willing to resume nuclear tests to do so. They point to a 1997 statement
by Siegfried Hecker, then Director of Los Alamos: “with a CTBT [Comprehensive
Test Ban Treaty] it will not be possible to make some of the potential safety
improvements for greater intrinsic warhead safety that we considered during the 1990
time frame.”44 C. Paul Robinson, then Director of Sandia, stated in 1999:
As technology advances, opportunities will arise for improving the safety design
of nonnuclear systems of nuclear weapons, and we will, of course, pursue those
opportunities. While improvements to safety and security systems for nuclear
weapons can be developed and implemented without nuclear explosive testing,
several attractive technical concepts for enhancement of these features will be
foreclosed by the inability to test.45
RRW advocates claim that both CCRDs make revolutionary advances in safety
and use control despite the lack of testing. At the same time, in response to the
congressional goal of minimizing the likelihood of a return to testing, the designs
exclude some innovative designs that might further increase safety and use control
but that are not mature enough to be used without testing.
7. Reduce the consequences of an accident or attempted
unauthorized use that does not produce nuclear yield. [2, 3, 4, 5, 7]
Insensitive high explosive (IHE) is much less likely to detonate than is the
conventional high explosive (CHE) used on W76 and W88 warheads for submarine-
launched ballistic missiles. Accidental detonation of IHE or CHE would almost
surely not result in a nuclear detonation, but IHE would reduce the risk to production
workers, military personnel, and the public from a nonnuclear explosion and the
plutonium it would scatter. The first RRW would be used in place of some W76s.
43 Personal communication, Rob Nelson, Senior Scientist, Union of Concerned Scientists,
Nov. 22, 2006.
44 S.S. Hecker, “Answers to Senator Kyl’s questions,” attachment to letter from S.S.
Hecker, Director, Los Alamos National Laboratory, to Honorable Jon Kyl, Sept. 24, 1997,
in U.S. Congress. Senate. Committee on Governmental Affairs. Subcommittee on
International Security, Proliferation, and Federal Services. Safety and Reliability of the U.S.
Nuclear Deterrent. Senate Hearing 105-267, 105th Cong., 1st sess., 1997, p. 84.
45 “Prepared Statement by Dr. C. Paul Robinson,” in U.S. Congress. Senate. Committee on
Armed Services. Comprehensive Test Ban Treaty. Senate Hearing 106-490, 106th Cong., 1st
sess., 1999, p. 130.

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CRS-16
The designs seek to create the W76’s military capabilities in a larger, heavier
package; the competing RRW designs use some of that extra weight and volume for
IHE. RRW’s supporters point to the use of IHE as an advantage of RRW.
The reduced sensitivity of IHE comes at a price: IHE is less energetic than CHE,
so a warhead requires more IHE than CHE to initiate the nuclear explosion. While
the designs for the first RRW use IHE, the W76 uses CHE, so the W76 LEP must
also use CHE. As a result, a requirement to use IHE would force a switch from W76
LEP to RRW. LEP supporters recognize that IHE would improve safety in some
accident scenarios, but note that the W76 has not had a single accidental detonation
of its high explosive since its deployment in 1978, and that the Navy has high
confidence in the W76 LEP. Accordingly, they see the drawbacks of moving to
RRW as outweighing the safety benefits of moving to IHE.46
Warhead Characteristics: Design for Manufacturing and
Maintenance
When the laboratories developed warheads now in the stockpile, they gave such
characteristics as cost, ease of manufacture, and ease of dismantlement secondary
consideration at best. While there was some consultation with the plants, the priority
was “physics first.” In order to minimize weight, designers would use materials that
were hazardous, difficult to machine, or that produced massive waste streams, and
would call for hard-to-manufacture components and features. With the emergence
of SSP in the early 1990s and LEPs in the mid-1990s, the labs began to work much
more closely with the plants. With congressional RRW goals bearing on ease of
manufacture, cost, reduced use of hazardous material, and the like, both design teams
have collaborated intensively with the plants on how to make designs safer and easier
to manufacture, and have included some such features in the designs. More broadly,
teams and plants considered all aspects of a warhead’s life cycle in developing the
CCRDs. Note that many features under this heading lower costs, and that designing
warheads for safety of manufacture often makes for easier manufacturing.
8. Reduce the environmental burden imposed by warhead
production. [3, 4, 7] This goal seeks to reduce waste streams and potential harm
to the environment, and to improve worker safety. But it is much more than “just
green.” It contributes to other goals, such as making manufacturing easier and
reducing cost. For example, some current warheads use beryllium, which is toxic
and difficult to machine; neither CCRD uses beryllium. Both teams claim that new
RRW manufacturing processes will potentially reduce radioactive waste, and expect
that RRW nuclear explosive packages will reduce hazardous material usage. In
contrast, NEP components in LEPs must replicate, insofar as possible, original
specifications, including use of hazardous materials.
46 For further discussion, see U.S. Congress. House Committee on Armed Services, Panel
on Nuclear Weapons Safety, Nuclear Weapons Safety, Committee Print No. 15, 101st Cong.,
2nd sess., p. 26-33, by Sidney Drell, Chairman, John Foster, Jr., and Charles Townes; and
CRS Report RL32929, Nuclear Weapons: The Reliable Replacement Warhead Program,
by Jonathan Medalia, section titled “Might RRW Enable an Increase In Warhead Safety?”

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CRS-17
RRW’s critics recognize that RRW should be able to meet this goal, but argue
that LEP might meet it in other ways. LEPs could retain existing pits, reducing
hazardous material usage, while RRWs, at least for missiles, probably would require
new pits. Nonnuclear components, whether for LEPs or RRWs, could use equally
benign materials. NNSA could augment efforts to reduce waste in support of LEP.
9. Design warheads for safety of manufacture. [2] Both teams worked
closely with the plants to minimize the production steps needed. Both designs are
expected to eliminate roughly 1/3 of these steps through process simplification,
which in turn is expected to reduce worker radiation exposure and the waste stream
dramatically. Pantex states,
10 CFR 830 requires a more formal Documented Safety Analysis and
documented weapon response from the design agencies, safety
requirements/controls have increased at Pantex as a result. Tighter safety
requirements can restrict throughput. The design of both CCRDs has, from the
beginning, addressed safety concerns with a view to meeting Pantex safety
requirements and optimizing production.47
The use of IHE in the Competing Candidate RRW Designs (CCRDs) shows
how improved safety can facilitate manufacture. Pantex has “bays” and “cells” for
assembling and disassembling warheads. Bays and cells are reinforced-concrete
rooms; cells are designed for a higher level of containment and, therefore, for more
dangerous operations. At Pantex, 39 assembly bays and 7 cells are authorized to
perform nuclear explosive operations, so the requirement to use cells for operations
involving CHE and plutonium limits throughput.48 Because IHE is so much safer to
handle, work with IHE and plutonium can be done in bays as well as cells.
RRW advocates state that LEPs require manufacturing with hazardous materials
and complex processes that RRWs eliminate. LLNL states that its new process for
fabricating RRW pits reduces radiation waste 10-15 percent and worker radiation
exposure 15-20 percent, and that the CA design replaces hazardous materials used
in several components with materials that are non-hazardous and commercially
available. The risk of safety issues, in this view, is higher for LEPs than RRWs.
“Optical isolation” provides another example of how a new approach can
improve ease and safety of manufacturing. An enormous concern at Pantex is that
electrostatic discharge (ESD) — a spark, such as from static electricity or lightning
— could detonate CHE in a primary, potentially killing workers and scattering
plutonium. This concern has in the past caused Pantex to halt operations, sometimes
for months. Guarding against it is difficult; for example, the steps to move a CHE
component within Pantex take four hours because of the need to protect against ESD.
The NM design includes a technique called “optical isolation,” which would interrupt
47 Information provided by Pantex Plant, Sept. 19, 2006.
48 Pantex plans to add three cells by the RRW FPU date (now planned for FY2012) through
a cell upgrade program. Information provided by Pantex Plant, Sept. 19, 2006.

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CRS-18
a direct electrical detonation path to a warhead’s detonators. Pantex states that this
approach, if successful, would “reduce or eliminate the need for ESD controls.”49
Kent Fortenberry, Technical Director of the Defense Nuclear Facilities Safety
Board,50 provided CRS with the following comments on safety aspects of RRW:
Although the Board can point to areas where significant incremental
improvements have been achieved in the safety of ongoing nuclear weapon
operations, the RRW program represents the potential for a substantial step
change improvement in safety.
The Board has not reviewed the details of the RRW design proposals. It is
possible that certain design attributes could introduce new hazards or safety
concerns. In fact, the Board is aware of at least one design feature that is
undergoing additional development to address a potential safety impact.
However, the current RRW design proposals contain attributes that should
provide a marked increase in the safety of nuclear weapon manufacturing,
surveillance, maintenance, and dismantlement. Examples include design
attributes that eliminate hazardous materials, reduce and simplify processing
steps, reduce the required disassembly and inspection operations, and reduce
waste streams. Other examples include design attributes that have the potential
to mitigate or eliminate the impact of abnormal or accident conditions such as
fire, electrostatic discharge, lightning, mechanical impact, and other scenarios
that might create the potential for a high explosive violent reaction or inadvertent
nuclear detonation.51
Critics hold that LEP might also increase safety. While all RRW components
would have to be manufactured and assembled, critics maintain that LEPs
manufacture and replace fewer components on average; some LEPs require complete,
and others require partial, disassembly and reassembly.52 Further, in this view, means
other than RRW can improve safety. Safety of manufacture is constantly improving
through better building maintenance, more worker training, and so on. Pantex states
it has improved safety practices for handling high explosives, such as by reducing the
number of times an explosive component must be lifted by hand, and has changed
some solvents in response to an accident some years ago in which ESD was thought
to have ignited a small fire in a flammable solvent.53 Because of such steps and an
increased focus on “safety culture,” it may be argued, the plants have very good and
improving safety records. For example, NNSA stated that Pantex has never had an
ESD event causing death or serious injury, though it has had ESD events that
49 Information provided by Pantex Plant, Sept. 19, 2006.
50 The Defense Nuclear Facilities Safety Board was created by Congress 1988 “as an
independent oversight organization within the Executive Branch charged with providing
advice and recommendations to the Secretary of Energy ‘to ensure adequate protection of
public health and safety’ at DOE’s defense nuclear facilities.” U.S. Defense Nuclear
Facilities Safety Board. “Who We Are,” at [http://www.dnfsb.gov/about/index.html].
51 Personal communication, Kent Fortenberry, Technical Director, Defense Nuclear
Facilities Safety Board, Sept. 14, 2006.
52 Information provided by Pantex Plant, Sept. 19, 2006.
53 Information provided by Pantex Plant, Sept. 15, 2006.

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CRS-19
interrupted production, and Pantex stated that the last time a Pantex worker was
killed or seriously injured by an accident involving CHE was in 1977.54
10. Design warheads for ease of manufacture. [4, 6, 7] Pantex wanted
the designs to minimize assembly and disassembly steps. Both teams treated this as
a design priority. They found that relaxing the requirement for a high yield-to-weight
ratio simplified manufacturing. Further, in past practice, manufacturing tolerances
of parts were driven to be the best achievable. In contrast, tolerances for CCRD
components are arrived at by simulations that relate tolerances to performance.
Relaxing tolerances makes manufacturing easier, reduces the number of units
rejected, increases throughput, and reduces waste, all of which lower cost. Los
Alamos provided two examples of how CCRDs could facilitate manufacturing:55
In manufacturing pits in the current stockpile, pits in process were taken from
manufacturing stations to separate work stations to be measured and certified, a
time-consuming process. In contrast, the higher margin of CCRDs is expected
to permit tolerances to be relaxed enough to enable gauging and certification of
pits in process on production machines. This reduces manufacturing time, cost,
and floor space.56
The new process for manufacturing RRW pits will utilize a direct casting process
that greatly reduces the required number of subsequent process steps.
The NM design also makes assembly and disassembly easier in other ways. It
minimizes the use of adhesives, which add time and complexity to assembly because
they must be cured for the proper time and at the proper temperature, and may
prevent nondestructive disassembly. The NM design reduces part count, assembles
nonnuclear components into subassemblies before delivery to Pantex, and reduces
the number of assembly steps that must be performed in cells or bays. LLNL states
that its new process for fabricating RRW pits holds the potential to increase
manufacturing efficiency. It eliminates some manufacturing bottlenecks. It reduces
the number of workstations and process steps by about 25 percent. LLNL has
proposed replacing a major component that, for current warheads, was made on a
mile-long production line with a new-design RRW component that could be
manufactured commercially.57
Using less hazardous material makes manufacturing easier. For example, Pantex
states, “before work can be done on explosives a Documented Safety Analysis must
54 Information provided by NNSA Pantex Site Office, Dec. 11, 2006, and by Pantex Plant,
Sept. 19, 2006.
55 Discussion with Los Alamos staff, Sept. 15, 2006.
56 [Note by CRS] Reduction in floor space for operations with nuclear materials is
important because adding such space through new construction costs, by LANL’s estimate,
$30,000 per square foot.
57 Information provided by Lawrence Livermore National Laboratory, Nov. 27, 2006.

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CRS-20
be established for safe operations. Developing and approving this basis constitutes
a large portion of the workload at Pantex, and is simplified by the use of IHE.”58
Critics argue that LEP may also offer manufacturing efficiencies. A study of
November 2006, discussed below under Issues for Congress, has increased the
estimate of pit life from 45-60 years to 85-100 years or more. This estimate, if used
as the basis for stockpile decisions, would reduce the need for pit production for
LEPs. The vast majority of warhead components are nonnuclear; manufacturing
improvements for them can be made equally for LEP or RRW. Ease of manufacture
for RRWs compared to LEPs depends on the warhead to be life-extended. If a
warhead has IHE, good margins, limited hazardous material, and better than average
safety and use control, and does not require a new pit, then the LEP may involve less
manufacturing difficulty than an RRW. If the LEP involves CHE and other hazardous
materials, no clear statement can be made about relative manufacturing effort.
11. Design warheads for ease of maintenance. [6] For current
warheads, the practice has long been to remove 11 units of each warhead type per
year from fielded weapon systems. These units are disassembled at Pantex and
surveilled throughout the Complex, imposing a large burden on the Complex. This
practice also imposes a burden on the Air Force and Navy because they must remove
warheads from storage, silos, or submarines, send them to DOE, and replace them
with spares. In contrast, both CCRDs envision two surveillance removals per year,
achieving this reduction through improved surveillance and non-destructive
evaluations and through calibrated shelf life units. The latter are identical to deployed
warheads, but the plants retain them. They are calibrated to fielded warheads in the
sense that they experience the same environments relevant to particular aging
phenomena that fielded units experience. The documentation for each unit, from
manufacturing onward, will also be much more comprehensive than for warheads
now in the stockpile.59
Laboratory sources indicate that both teams are also considering embedding
sensors inside warheads to provide data on a warhead’s environmental conditions,
such as temperature, vibration, and hydrogen level, which help estimate performance
and lifetime, and on deterioration, such as cracking or corrosion. Other sensors
would report on a weapon’s status, such as if valves are in their expected
configuration. They would not replace surveillance, but would increase the amount
and types of data that can be gathered by nondestructive means and reduce the
disassembly required for surveillance. No decision has been made on using these
sensors. CCRDs also have characteristics that make disassembly easier, such as
modular design and minimal use of adhesives. Warheads are disassembled not only
at the end of their service lives to remove them from the stockpile, but also for
surveillance, repairs, and other maintenance, so ease of disassembly is important
throughout a warhead’s service life.
58 Information provided by Pantex Plant, Sept. 19, 2006.
59 Information provided by Lawrence Livermore National Laboratory, Jul. 27, 2006, and
Los Alamos National Laboratory, Sept. 15, 2006.

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CRS-21
Critics assert that some RRW techniques for ease of maintenance might be
applied to current warheads, such as replacing limited-life components (like batteries)
in current warheads with limited-but-extended-life components being developed for
RRWs. They note that the current stockpile has calibrated shelf life units, so this is
not a new advantage for RRW. They fear that data from onboard sensors may not
lead to correct diagnosis of warhead problems. Commenters pointed to an instance
decades ago in which a part made of one material was destroyed by vapor normally
released by another part, forcing a change of the material used to fabricate the first
part. One commenter asks if embedded sensors would have understood the
vulnerability of the original component. Robert Peurifoy, former Vice President of
Technical Support, Sandia National Laboratories, Albuquerque, NM, states, “It is my
opinion that the best way of searching for material incompatibilities is by conducting
accelerated aging tests.”60 The critics’ greatest concern with the RRW surveillance
plan is that while examining fewer warheads each year would reduce the surveillance
burden, it would also reduce the sample size on which reliability estimates are based,
reducing confidence in reliability.
12. Increase warhead longevity. [1] RRW may increase longevity
somewhat. For example, some current warheads use exotic materials with
undesirable aging properties, while CCRDs use some materials with longer expected
life. Also, making surveillance and disassembly easier should make it easier to detect
and repair problems.
Long service life, however, is not a prime concern of the program and does not
appear to be an advantage of RRW over LEP. NNSA’s vision of the Complex of
2030 calls for “a continuous design/deployment cycle that exercises design and
production capabilities …”61 Under this plan, RRWs might stay in service for two
or three decades, comparable to the originally-anticipated service lives of current
warheads, rendering RRW longevity moot. LLNL states, “Supporters of RRW also
do not claim that RRW will provide significant improvement in warhead longevity.
Current warheads typically last two or three decades, and with LEP can be made to
last two or three decades longer. RRW may make some improvement on that,
especially for some key hard-to-manufacture components, but this is not a major
feature of the program.”62 NNSA states:63 “NNSA developed the LEP Program to
extend the stockpile lifetime of a warhead or warhead components at least 20 years
with a goal of 30 years.” “The B61 LEP will extend the life of the B61 for an
additional 20 years.” “The W76 LEP will extend the life of the W76 for an
additional 30 years.” As noted, the Navy has high confidence in the W76 LEP.
60 Email, Sept. 1, 2006. These tests subject warheads from the stockpile, as well as
components and materials, to high temperature and temperature cycling, generally for a year
or more, to speed up the aging process so as to gain early warning of potential deterioration.
61 U.S. Department of Energy. National Nuclear Security Administration. Office of Defense
Programs. Complex 2030: An Infrastructure Planning Scenario for a Nuclear Weapons
Complex Able to Meet the Threats of the 21st Century, DOE/NA-0013, October 2006, p. 9.
62 Information provided by Lawrence Livermore National Laboratory, Sept. 19, 2006.
63 Department of Energy, FY 2007 Congressional Budget Request, Volume 1, p. 79.

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CRS-22
Experts on both sides agree that SSP, surveillance, and LEPs have extended the
life of current warheads and can continue to do so. They disagree on how long LEP
will be able to maintain high confidence in current warheads, though the argument
is hypothetical on both sides. Those favoring RRW argue that unexpected
degradations might arise that will be beyond the ability of SSP to anticipate, and of
LEP to resolve, in a timely manner. LEP’s supporters feel that as SSP improves, the
ability to predict problems and maintain warheads will also improve and the range
of unanticipated problems that could cause LEP to fail will diminish.
Stockpile Characteristics
13. Fulfill current mission requirements of the existing stockpile.
[2] The first RRW would have the nuclear yield of the W76, or perhaps slightly
less.64 It would be placed in the Mk5 aeroshell, now used only for the W88 warhead,
instead of the Mk4, which carries the W76. The Mk5 provides somewhat more
accuracy than the Mk4. The increased accuracy of the Mk5 would offset any loss of
effectiveness stemming from a slight yield reduction of the RRW, so that the
RRW/Mk5 unit could fulfill mission requirements of the W76/Mk4.
14. Avoid requirements for new missions or new weapons. [5, 6, 8]
Even though congressional language leaves unclear if RRW is to be a new warhead,
it is clear that the selected RRW design would replace existing warheads with new-
design warheads that can perform current missions using existing aeroshells and
missiles. At the same time, the CCRDs are not tailored for new missions that have
been of concern to some in Congress. They do not rely on new physical principles
for the nuclear explosion, and are not designed to produce new nuclear effects such
as electromagnetic pulse. The design goal for RRW is to match the yield of the W76,
which it replaces. While yield might decrease slightly, it will still be about that of
the W76. RRW will not be a low-yield “mini-nuke.” Nor will it be a “bunker
buster,” or earth penetrator, and indeed the competing designs do not incorporate the
ruggedness needed for that purpose.
LEP’s supporters point out that retaining existing warheads through LEPs would
avoid new ones. Whether existing warheads would be used for new missions would
be a political and military decision.
Others favor having the ability to modify existing warheads, or to develop new
ones, for new missions. In this view, the ability to respond to potential future threats
is essential, and can most surely be met through resumed nuclear testing.65
15. Focus initial efforts on replacement warheads for submarine-
launched ballistic missiles (SLBMs). [3] Several rationales are stated for this
goal. (1) The W76 is the most numerous warhead in the stockpile, so its failure
would severely weaken the U.S. deterrent force. Using RRWs, life-extended W76s,
64 Information provided by Los Alamos National Laboratory, Sept. 20, 2006.
65 Information provided by Robert Barker, former Assistant to the Secretary of Defense for
Atomic Energy, Nov. 29, 2006.

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CRS-23
and W88s would reduce that risk. (2) The W76 is old, first deployed in 1978. (3) If
the current number of W76s is retained, production schedules would place the first
RRW in competition with the W76 LEP for Complex resources. Planning for the
first RRW to substitute for some W76 LEP production could lessen that competition.
The RRW designs respond to this goal by packaging the military capabilities of
the W76 into a design that can be used in the Mk5. The designs were required to
maintain the same weight, center of gravity, and other characteristics of the W88 so
RRWs could be used in the Mk5. DOD insisted on this approach to avoid the time
and expense of building and flight testing new aeroshells or missiles for the Navy.
Supporters of LEP argue that W88s hedge against failure of the W76. They
state that the W76 LEP, with the first production unit scheduled for FY2007, will
provide an SLBM warhead with an established pedigree, and note that NNSA expects
that the LEP will extend the warhead’s life by 30 years.66 They ask why the Navy
would want to use a new, untested warhead to replace one that has been in the
inventory for nearly three decades, that is supposed to be effective for decades more,
and for which maintenance and handling procedures are well understood. DOD and
DOE have both invested heavily in the LEP so that, in this view, completing the full
W76 LEP production is the most cost-effective way to provide SLBM warheads
needed for the stockpile. Barry Hannah, Chairman of the RRW POG, stated,
The W76 LEP that is currently underway is an excellent program in terms of
technology, schedule, and cost. I believe it meets the Navy’s needs. While it
makes many changes and some upgrades to components, it also includes changes
that increase margins in order to compensate for problems or uncertainties that
component changes or age-related degradation might introduce.67
16. Complement or replace LEP. [2] Supporters hold that RRWs would
complement LEPs very well. Current warheads were designed with the help of an
extensive nuclear test program, were designed to meet Cold War requirements, and
have been repeatedly certified without nuclear testing to be safe and reliable, but they
cannot be modified to meet the many congressional goals discussed here. In contrast,
RRWs would not be tested, would be designed to meet post-Cold War requirements,
arguably could be certified without nuclear testing to be safe and reliable, and could,
as a result of using a new design, meet congressional goals.
DOD, NNSA, and political leaders could in the future decide to replace current
warheads instead of having them undergo LEPs. Any such decision would hinge on
the success of the RRW program and LEP, the perceived need for nuclear weapons,
66 U.S. Department of Energy. Office of Chief Financial Officer. FY 2007 Congressional
Budget Request. Volume 1, National Nuclear Security Administration. DOE/CF-002,
February 2006, p. 79, at [http://www.mbe.doe.gov/budget/07budget/Content/Volumes/
Vol_1_NNSA.pdf].
67 Information provided by Dr. Barry Hannah, SES, Branch Head, Reentry Systems,
Strategic Systems Program, U.S. Navy, telephone conversation with the author, Oct. 23,
2006.

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CRS-24
and the willingness of Congress and the Administration to support such replacement.
It is thus premature to speculate on whether RRWs will replace current warheads.
The Air Force raises questions about the effectiveness of LEPs, and makes the
following assertions:
! LEPs are complicated. Current warheads were not designed to be
refurbished, so disassembly is difficult.
! Some LEP components are made with archaic processes and hazardous
materials.
! LEPs are time-consuming. The Air Force was convinced by 1992 that the
W87 ICBM warhead needed certain changes, and the Secretary of the Air
Force sent a letter to the Secretary of Energy in that year asking DOE to
make the changes. It took until 1999 for DOE to deliver the FPU to the
Air Force.
! It is preferable not to rely on old warheads, though the first B61 has been
in the stockpile since 1968. Warheads deteriorate over time, and a
warhead in good condition now might, it is argued, suffer severe corrosion
and become unreliable in 10 or 15 years.
! Margins in some current warheads were thin by design, and a series of
changes could erode confidence that the margin remained sufficient.
! The foregoing factors raise questions about whether DOD can have
confidence in the ability of the Complex to execute LEPs as a long-term
sustainment strategy.68
Critics expect that LEP will enable NNSA to maintain current warheads for
many years. As noted under Goal 15, a Navy official shared this view in the case of
the LEP for the W76. Critics recognize that it may be costly to bring back out-of-
date processes and hazardous materials, but argue that cost must be weighed against
the cost of designing, producing, and deploying perhaps thousands of RRWs and
against the uncertainties arising because RRWs will not undergo nuclear tests.
17. Reduce the number of nondeployed warheads. [2, 4, 5, 6] The
President approves the number of U.S. warheads annually in the Nuclear Weapons
Stockpile Memorandum. The number of deployed warheads depends on perceived
military and political needs. DOD also retains many nondeployed warheads to hedge
against technical and geopolitical risk. The former arises from the prospect that an
existing warhead type might develop a defect that NNSA would have difficulty
remedying. Geopolitical risk arises from the prospect that the Complex could not
manufacture new warheads fast enough to respond to such threats as a major
expansion of an adversary’s nuclear forces.
68 This paragraph is based on information provided by a senior Air Force official, interview
with the author, Sept. 26, 2006.

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CRS-25
RRW’s supporters claim that RRW would permit a reduction in nondeployed
warheads for several reasons: RRWs would be less likely to develop defects because
of increased margins; defects could be corrected more easily because RRWs would
be designed for ease of surveillance and disassembly; a modified Complex could
produce RRWs in time to respond to threats because they would be designed for ease
of manufacture, and fewer types of warheads would be needed as backups.
Regarding the latter point, at least two warhead types are currently available for each
delivery system. This approach hedges against the prospect that a failure of one
warhead type would render an entire delivery system unusable until the problem was
fixed, impairing the U.S. deterrent. Each warhead, however, is designed for use on
only one type of delivery vehicle. In contrast, RRWs designed for one delivery
system could be used on another. While the first RRW is designed for use on
SLBMs, RRW supporters point out that it is designed so it could fit into ICBM
aeroshells69 with slight modifications, such as adjusting ballast. Using this approach,
an RRW intended for SLBMs could back up ICBM warheads, and vice versa, and an
RRW for cruise missiles could back up gravity bombs, and vice versa.
LEP supporters reject the argument that many nondeployed warheads are needed
to hedge against technical problems. In their view, surveillance and life-extension
programs have shown a continually-improving ability to find and fix problems. They
expect that too few RRWs would be built to arm both the intended and alternate
delivery vehicles because building enough to arm both would be at odds with the
goal of fewer nondeployed warheads. But LEP supporters believe it makes sense to
retain nondeployed warheads to hedge against geopolitical risks not detected in time
by intelligence. In their view, a modified Complex building RRWs could not
compensate for that risk if the nondeployed stockpile were to be reduced sharply.
They also express concern that having fewer warhead types would magnify the
consequences of a failure of one such type.
Nuclear Weapons Complex
Congress has been concerned for decades about the size, efficiency, and cost of
the Complex. At issue are how to RRW and LEP will bear on upgrading the
Complex and maintaining its skill base.
18. Support upgrading of Complex capabilities. [2, 3, 4, 5, 6] For
decades, analysts have noted the poor condition of the production plants, which have
many buildings dating from World War II. Secretary of Defense Donald Rumsfeld
wrote, “Since the end of the Cold War, ... our nuclear infrastructure has atrophied.
... it needs to be repaired to increase confidence in the deployed forces, eliminate
unneeded weapons, and mitigate the risks of technological surprise.”70 He noted that
the Nuclear Posture Review of 2001 called for a responsive infrastructure as part of
its New Triad. General James Cartwright, Commander, U.S. Strategic Command,
stressed the importance of this proposed upgrade: “an efficient and more responsive
69 These aeroshells are the Mk12A, which carries the W78, and the Mk21, which carries the
W87.
70 U.S. Secretary of Defense. “Nuclear Posture Review Report: Foreword.” Jan. 10, 2002,
p. 3, at [http://www.defenselink.mil/news/Jan2002/d20020109npr.pdf].

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CRS-26
nuclear weapons infrastructure ... is the essential element needed to ensure our
weapons are safe, secure, and reliable, to ensure we can respond to both technological
and political surprise, and to reduce our current stockpile of nuclear warheads.”71
Thomas D’Agostino, NNSA Deputy Administrator for Defense Programs, said,
“We have worked closely with the DoD to establish goals for ‘responsiveness,’ that
is, timelines to address stockpile problems or deal with new or emerging threats. For
example, our goal is to understand and fix most problems in the stockpile within 12
months of their discovery.”72 To meet these goals, the Secretary of Energy Advisory
Board’s Task Force on the Nuclear Weapons Complex Infrastructure, and NNSA in
its “Complex 2030,” have proposed alternative plans.73 While they differ in specifics,
both would consolidate fissile material, eliminate some redundancies in R&D
facilities, and consolidate elements of the current Complex. Both assume Complex
reconfiguration completed around 2030, and a Complex-in-transition supporting a
stockpile-in-transition. Even if the United States proceeds with RRW, the Complex
would, for decades, need to support current warheads and RRWs simultaneously.
Opinions differ on the link between RRW and a responsive infrastructure.
RRW’s supporters maintain that RRW would permit a more efficient Complex.
They assert that it would take fewer steps to make NEP components for RRWs than
for LEPs, simplifying production. Looser tolerances would result in fewer rejected
parts. Modular designs and elimination of conventional high explosives would
permit greater throughput at Pantex. Reducing hazardous materials, it is argued,
would enable more manufacturing to be done away from the most costly floor space
and might permit more work to be contracted out. Each design eliminates at least
one hazardous materials production unit, enabling fewer and smaller facilities to treat
waste from production. In contrast, supporters claim, LEP locks the Complex into
existing designs, materials, and processes.
LEP’s supporters note that NNSA routinely upgrades the Complex, such as by
introducing new manufacturing processes, to support LEP. Further, it has for several
years received funds for the Facilities and Infrastructure Recapitalization Program,
with an FY2008 request of $293.7 million, to improve the Complex. While RRW
might permit a more capable Complex by increasing efficiency, LEP might require
less new capability and capacity. For example, LEP’s supporters question the
advantage of dismantling thousands of warheads while building facilities able to
manufacture large numbers of RRWs to respond to a threat. They ask if it might be
71 General James Cartwright, Commander, U.S. Strategic Command, “Statement Before the
Strategic Forces Committee, Senate Armed Services Committee, on Global Strike Plans and
Programs,” Mar. 29, 2006, p. 13-14; available at [http://armed-services.senate.gov/
statemnt/2006/March/Cartwright%20SF%2003-29-06.pdf].
72 “Statement of Thomas P. D’Agostino ...,” Apr. 5, 2006, p. 4.
73 For the Task Force plan, see U.S. Department of Energy. Secretary of Energy Advisory
Board. Nuclear Weapons Complex Infrastructure Task Force. Recommendations for the
Nuclear Weapons Complex of the Future, 2005. For NNSA’s plan, see U.S. Department of
Energy. National Nuclear Security Administration. Office of Defense Programs. Complex
2030: An Infrastructure Planning Scenario for a Nuclear Weapons Complex Able to Meet
the Threats of the 21st Century, DOE/NA-0013, October 2006.

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CRS-27
more responsive to maintain existing warheads than to add that capacity. Further,
they argue, if DOD needed a few new-design warheads to attack specified targets, the
laboratories could probably build them using their current facilities.
Some recognize the need to modernize the aging production plants but question
if modernizing the Complex around RRW is the right approach. They argue that
narrowing the range of materials that the Complex can handle, such as by eliminating
CHE and some toxic materials, make the infrastructure less capable and thus less
responsive. They fear that streamlining the Complex with fewer warhead types and
modular warhead design reduces the diversity of its workload while increasing the
risk of a failure affecting much of the nuclear stockpile.
19. Exercise skills of the Complex. [2, 3] DOE, NNSA, and Complex
staff feel strongly that it is imperative to exercise the complete set of skills in the
Complex in order to maintain them, and state that the RRW program will do this
while LEP does not. According to DOE,
The complete set of skills is required to protect against technological surprise as
well as to have the capability to design a weapon with new military
characteristics, should it be required. The RRW design program looks at the
overall weapon design, not just those few components that get replaced in an
LEP. Additionally, the RRW has provided the opportunity to develop safety,
security, and use control features; this cannot be done for an LEP which is
limited to extending the life of the existing design.74
According to Sandia,
By exercising all of the skills and capabilities required to design, test, qualify,
and produce complete systems on a regular basis, those skills are ready and
available to address higher-priority problems on a moment’s notice. The
Complex must exercise all of the skills required, not just the science, modeling,
and simulation skills, to have them available. These skills include but are not
limited to a strong scientific foundation, systems analysis, engineering analysis,
design definition, systems engineering, component design, test and evaluation,
component production, and weapon assembly and disassembly. Like an athlete,
you cannot exercise 20 percent of the skill base and expect to function at 100
percent on game day. You have to practice all parts of your craft or you will not
be able to perform up to expectation when a problem arises unexpectedly.75
Livermore provided the following response, with which Los Alamos concurs:
One of the central goals of RRW is to enable the nuclear weapons complex to be
more responsive to future unforeseen problems. ... Because RRWs are designed
to be easier to manufacture, certify, and maintain, they can make the complex
more responsive. When problems arise, the complex will have the demonstrated
capability to replace problem warheads with more reliable and maintainable
warheads. Thus risk mitigation can be borne by the infrastructure rather than by
the large inventory of reserves. Whatever problems arise, a complex and work
74 Information provided by NNSA, Aug. 11, 2006.
75 Information provided by Sandia National Laboratories (NM), Jul. 25, 2006.

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CRS-28
force that is experienced and capable of producing and fielding warheads that
meet the needs of the day rather than dedicated to perpetuating the designs of
another era has a better chance of being able to respond.76
NNSA prefers a continuous cycle of design and deployment, as noted, in part
to exercise Complex capabilities, rather than conducting LEPs of RRWs in the
future. Similarly, a SEAB Task Force argued for an ongoing program of RRW
design and production on a five-year cycles.77 In discussions with CRS in September
2006, a task force member argued that this approach, by using the latest design and
production methods rather than sustaining old technologies, would aid recruitment,
retention, and capability development in the Complex workforce. LANL claims that
RRW would exercise design skills better than LEP. Because RRW is a new design,
designers must confront the full range of tradeoffs simultaneously, balancing yield,
weight, ease of manufacture, cost, use control, safety, reduction of hazardous
material, etc. In contrast, LANL argues, an LEP constrains choices for the nuclear
explosive package because replication is required to minimize divergence from
parameters that were validated by nuclear testing.
LEP’s advocates offer several responses: (1) LEP also exercises design,
assessment, and production expertise. Design expertise is needed to ensure that a
minor change introduced by an LEP will not create a problem, such as a material
incompatibility, elsewhere in the warhead. Production expertise is needed in the
manufacture of replacement components and in exchanging new for old components.
Certification expertise is needed to ensure that a life-extended warhead will meet
safety, reliability, and other conditions required for its use in the stockpile. (2) Most
warhead problems, they claim, will be discovered after several decades, and current
warheads are very well understood, so the unforeseen problems are less likely for
LEP than for RRW. (3) Retaining and maintaining many inactive warheads provides
a more timely hedge than counting on a Complex in transition to produce enough
RRWs. (4) An advantage claimed for RRW is that it would be easier to maintain
over the long term. It is inconsistent for RRW supporters to argue that RRWs will
have long service lives and that RRWs should be replaced on an ongoing basis.
LEP proponents argue that NNSA could maintain the ability to design and
produce new warheads by designing new warheads, producing them in small
quantities, and not deploying them, thereby avoiding reliability risks and production
costs of introducing new warheads into the stockpile. RRW supporters respond that
it would be costly to design new warheads and develop production and certification
processes for small builds as a skill maintenance program. They see this approach
as far less effective than a program to deliver actual warheads to DOD. LEP
proponents point out that it would be less costly to build small rather than large lots,
and that large builds would impose on DOD the cost to replace many warheads and
on DOE the cost to dismantle or store returned warheads.
76 Information provided by Lawrence Livermore National Laboratory, Jul. 26, 2006.
77 U.S. Department of Energy. Secretary of Energy Advisory Board. Nuclear Weapons
Complex Infrastructure Task Force. Recommendations for the Nuclear Weapons Complex
of the Future. Jul. 13, 2005, p. 13.

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CRS-29
Cost
20. Reduce life cycle cost. [2, 4, 5, 6, 7, 8] There are no estimates for the
total cost of the RRW program, or even for developing, manufacturing, and
deploying the first RRW. Because the program is in early stages, there are many
unknowns that will affect cost, such as design and production details and the number
to be procured. Nonetheless, RRW’s supporters assert that many aspects of the
competing RRW designs are intended to reduce cost.
! The designs emphasize ease of manufacture and assembly, and use of
safer and less costly materials.
! RRW should lower surveillance costs. The legacy stockpile consists of
eight basic designs and many modifications within each design.
Surveillance data for each are required. An RRW-based stockpile, it is
argued, would have far fewer basic designs and modifications. Further,
surveilling each warhead type would be less costly. The plan is to
withdraw fewer units for surveillance, and embedded sensors, if used,
could report on a warhead’s condition without requiring disassembly.
! Enhanced use-control features would permit a modification of physical
security practices, perhaps slowing the growth of security costs.
! Increased design margins should make RRWs more tolerant of design or
manufacturing flaws, or of changes due to aging or other causes. As a
result, designers might be able to judge that a corrective action was not
needed to fix certain problems, lowering maintenance cost.
! Ease of disassembly and reduction of hazardous materials would reduce
cost of final dismantlement and any disposal of components when an
RRW is to be retired.
! RRW costs should be more predictable than those of LEPs because LEPs
must use some archaic technologies that will become increasingly difficult
to maintain, while RRWs would have all-new components.
! RRW, by permitting DOD to have fewer nondeployed warheads, would
result in fewer units undergoing LEPs or routine maintenance.
LEP supporters counter that LEP costs are more predictable because LEP would
maintain warheads with which the Complex has considerable experience. They
argue that extending the life of existing warheads would reduce manufacturing costs,
avoid costs of training and equipment needed to handle new warheads, and postpone
for decades the retirement of thousands of warheads. They note that LEPs consume
a small fraction of the total stockpile stewardship budget, for example $238.7 million
(requested), or 3.7 percent, for FY2008. Another program, Stockpile Systems,
involves routine maintenance of warheads. Its FY2008 request is $346.7 million, or
5.4 percent of the stewardship budget. LEP supporters doubt that RRW could reduce
these costs by much, especially because they expect the large body of relevant
experience to hold down costs for maintaining or life-extending current warheads.

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Advocates of LEP wonder how many decades it would take for the savings that
RRW might yield to offset the large investment costs. They see any savings from
fewer nondeployed warheads as being at risk if more RRWs must be built to respond
to unforeseen threats. They note that adjusting costs and savings for net present
value, which takes into account the time value of money by placing heavier weight
on costs and savings early in a project’s life, would further delay reaching that
point.78 A second LEP of a current warhead years hence might cost less cost than the
first because the certification procedures, manufacturing processes, equipment, and
materials needed for the first LEP could be used in subsequent LEPs if the items to
be repaired were identical. They argue that RRW maintenance costs would be
nonnegligible if RRW, like other new products, had “birth defects” in design or
manufacture. They doubt that RRW’s improved use-control features would lead
Congress and the Administration to reduce physical security.
It does not appear that reducing the number of nondeployed warheads in storage
would generate large savings for DOD. In response to a CRS question to the Air
Force about the annual cost of maintaining its non-deployed warheads, the Air Force
responded, “Most AF costs are associated with overall manpower, support equipment
and facilities. The majority of these overhead costs do not vary directly in proportion
to the quantity of weapons on hand.”79 A senior Air Force official stated that storage
of nuclear weapons is a fixed cost, with the size of the security force driven by
storing nuclear weapons, not by the number of weapons. Nor did this individual see
RRW resulting in fewer storage sites.80
Cost will be a critical factor in the decision on LEP or RRW. Yet there are
serious questions about the validity of any 30-year life-cycle projection, especially
one with such great unknowns: what engineering details must be solved to move
from a preliminary to a final RRW design, how many warheads must the Complex
support, how would the Complex support a mixed force for decades while LEPs were
being phased out and RRWs were being phased in, and what will the reconfigured
Complex look like. Nonetheless, cost studies can be of value even if they are
preliminary, or can provide only relative costs, or note uncertainties that must be
resolved to produce a firmer cost estimate. The cost section of the RRW report that
Congress mandated in the FY2006 National Defense Authorization Act (P.L. 109-
163, Section 3111) will thus merit close attention.
78 For further information on net present value, see U.S. Department of Defense. Office of
the Under Secretary of Defense for Acquisition, Technology, and Logistics. “Contract
Pricing Reference Guides,” at Defense Procurement and Acquisition Policy website, [http://
www.acq.osd.mil/dpap/contractpricing/vol2chap9.htm].
79 U.S. Air Force, “Answers to Questions from CRS on RRW,” Sept. 25, 2006.
80 Information provided by a senior Air Force official, interview with the author, Sept. 26,
2006.

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Issues for Congress
Several issues that bear on the future of the U.S. nuclear weapons enterprise cut
across many of the goals listed above. This discussion presents some of them, along
with questions that Congress may wish to consider.
How much is enough? Many of the 20 goals are of the “more is better”
variety: more reliability, more longevity, more safety, more security, more ease of
manufacture. Yet each goal, while beneficial, imposes costs. Incorporating multiple
safety and use control features into RRWs would add costs. Some goals impose
design constraints that make it harder to reach other goals. Safety and use-control
features add to the complexity of CCRDs, which might slightly reduce reliability.
In some cases, the benefits sought may be questioned. While the CCRDs avoid the
Trinity exception, Congress may wish to ask how much weight should be given to
that scenario. It has never led to an accidental nuclear detonation, but past
performance does not guarantee future results. In other cases, benefits might be
adequately achieved by means other than warhead design, such as features and
systems external to the warhead. Congress may want to review some of the key
design tradeoffs and whether current warheads are good enough. For example, the
CCRDs demonstrate how much safety and use control can be obtained; as a separate
matter, it is up to Congress, along with NNSA, the Air Force, Navy, and others to
decide how much safety and use control they want and what tradeoffs they are willing
to accept to obtain it.
Will the Department of Defense accept RRWs? DOD has seemed split
in its support for RRW. DOD’s 2006 Quadrennial Defense Review gave it a mild
endorsement:
The Department is working with the Department of Energy to assess the
feasibility and cost of the Reliable Replacement Warhead and, if warranted,
begin development of that system. This system could enable reductions in the
number of older, non-deployed warheads maintained as a hedge against
reliability problems in deployed systems, and assist in the evolution to smaller
and more responsive nuclear weapons infrastructure.81
In contrast, the U.S. Strategic Command (USSTRATCOM), which operates
U.S. nuclear forces, strongly supports RRW. General James Cartwright, USMC,
Commander of USSTRATCOM, testified in 2006:
USSTRATCOM supports the Reliable Replacement Warhead (RRW) as the key
to transforming our aging Cold War nuclear weapons stockpile. RRW will
enhance our long-term confidence in the stockpile and reduce the need to retain
high numbers of hedge weapons while exercising the people, science, technology
base and facilities required for sustaining the nuclear weapons enterprise.82
81 U.S. Department of Defense. Quadrennial Defense Review Report, Feb. 6, 2006, p. 49.
82 General James Cartwright, Commander, U.S. Strategic Command, “Statement Before the
Strategic Forces Committee, Senate Armed Services Committee, on Global Strike Plans and
(continued...)

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Some concerns raised by DOD components are that handling and maintenance
procedures, aeroshells, and links between missile and warhead that have been
developed for current warheads might have to be changed if RRWs are introduced.
Current warheads have been tested and are certified to work, and LEPs are expected
to extend warhead life by 20 to 30 years. Why incur the added burden imposed by
RRW? Others feel that RRWs will reduce this burden once they are deployed.
Congress may wish to determine if DOD leadership strongly supports RRW at
present, and if not why not.
Will LEP or RRW better maintain warheads for the long term
without nuclear testing, or is a return to testing required? As noted
earlier, RRW advocates argue that minor changes from LEPs may reduce confidence
in current warheads over the long term, whereas RRW designs should provide high
confidence because they stay well within parameters defined by nuclear test data and
have wider margins than current warheads. LEP advocates respond that current
warheads have extensive nuclear test pedigrees, SSP has greatly improved
understanding of weapons science, and NNSA states that LEPs can extend the life
of current warheads by 20 to 30 years. In contrast, they feel that RRW breaks the
link between testing and certification. Still others maintain that neither LEP nor
RRW can provide confidence that warheads will work. In this view, both break the
link to testing, LEP because of the many changes inevitably introduced and RRW
because it will not be validated by testing. The only way to have confidence in the
stockpile, this position holds, is to resume nuclear testing. A fourth possible view
is that either LEP or RRW, despite their differences, could maintain weapons for the
long term. At any rate, a mixed RRW-LEP force would be inevitable for some years
if the United States moved to an all-RRW stockpile; having two types of warheads
designed decades apart to meet different requirements would lower the risk that a
single failure could put at risk much of the stockpile. CRS is aware of no advocates
for this fourth position.
Congress may wish to examine competing methods for maintaining a reliable
stockpile, problems that might arise in deploying a mixed LEP/RRW force and how
they might be addressed, and ramifications of maintaining a test moratorium or of
resuming testing.
Might there be gaps between current RRW designs and actual
RRWs? It is easy to think of the current designs as actual warheads. However, the
designs are preliminary, with considerable detailed design work remaining. Some
components might prove difficult to manufacture. Design defects might emerge.
Congress may wish to ask NNSA about where gaps between the current designs and
actual warheads might arise, and what the historical record indicates.
How do pit issues bear on the choice between RRW and LEP? A
pit is the fissile core of a modern thermonuclear weapon. It typically consists of a
hollow plutonium shell and other metal shells surrounded by chemical explosives.
82 (...continued)
Programs,” Mar. 29, 2006, p. 18; available at [http://armed-services.senate.gov/statemnt/
2006/March/Cartwright%20SF%2003-29-06.pdf].

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The plutonium shell is by far the most difficult and costly pit component to make,
and is the only one discussed here.
For many years, Rocky Flats Plant (CO) was the only site that made pits
certified for the stockpile, but it stopped making pits in 1989. NNSA has not made
certified pits since then. At present, the PF-4 (plutonium facility-4) building in
LANL’s Technical Area 55 (TA-55) is producing W88 pits at a low rate, with a
capacity of 10 pits per year expected by the end of FY2007.83 The first pits are
expected to be certified in FY2007. NNSA plans to complete work in FY2012 to
increase PF-4’s RRW pit production capacity to 50 certified pits per year, but does
not plan to increase PF-4’s capacity beyond that level.84
Pit life bears on the choice between RRW and LEP. Plutonium decays
radioactively in ways that may eventually impair pit performance. Until recently,
NNSA’s best estimate of pit life was 45-60 years. However, a November 2006 study
extended that estimate considerably. The study, by the JASON scientific advisory
group, reviewed an assessment of pit life by LANL and LLNL and found:
The assessment demonstrates that there is no degradation in performance of
primaries of stockpile systems [i.e., warheads] due to plutonium aging that would
be cause for near-term concern regarding their safety and reliability. Most
primary types have credible minimum lifetimes in excess of 100 years as regards
aging of plutonium; those with assessed minimum lifetimes of 100 years or less
have clear mitigation paths that are proposed and/or being implemented.85
This pit life “extension” would seem to favor LEP. Pits of current warheads are
difficult and costly to build, involve hazardous materials, and require elaborate safety
and security precautions. It is difficult to certify a remanufactured pit of current
design without nuclear testing; for example, LANL has spent several hundred million
dollars and many years to certify the nuclear performance of the W88 pits that PF-4
is manufacturing. If existing pits could remain in the stockpile for decades to come,
then there would be high confidence in them. DOD could have high confidence in
life-extended warheads, and fewer pits would have to be manufactured for many
decades, reducing LEP costs.
83 “Statement of Thomas P. D’Agostino, Deputy Administrator for Defense Programs,
National Nuclear Security Administration, Before the House Armed Services Committee,
Subcommittee on Strategic Forces,” Apr. 5, 2006, p. 7.
84 To deliver these pits, PF-4 would need a production rate of 80 per year. This excess
capacity would allow for pits rejected because of defects, disassembled for inspection during
production, retained for future surveillance, and held as spares. Information provided by
NNSA, Sept. 19, Oct. 4, and Nov. 2, 2006, and U.S. Department of Energy. “Notice of Intent
to Prepare a Supplement to the Stockpile Stewardship and Management Programmatic
Environmental Impact Statement — Complex 2030,” in U.S. National Archives and Records
Administration. Office of the Federal Register. Federal Register, Vol. 71, No. 202, Oct.
19, 2006, p. 61734.
85 R.J. Hemley et al., Pit Lifetime, JSR-06-335, MITRE Corp., Nov. 20, 2006, p. 1, available
at [http://www.nukewatch.org/facts/nwd/JASON_ReportPuAging.pdf].

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RRW’s supporters respond that RRW offers many advantages over LEP, such
as in safety, use control, and skill maintenance, as discussed earlier, independent of
pit life. They argue that wide margins will increase DOD’s confidence in RRW pits,
and that RRW pits will cost less to manufacture than pits for LEPs.
Pit life also bears on an issue that Congress has grappled with for years, pit
production capacity and the need for a new production facility. In the FY2006 budget
cycle, Congress deleted funds for a Modern Pit Facility, with a capacity of 125 pits
per year. NNSA argues that it needs more capacity than PF-4 offers. To that end, its
preferred Complex, “Complex 2030,” includes a Consolidated Plutonium Center
(CPC) with a capacity of 125 pits per year. John Harvey, Director of NNSA’s Policy
Planning Staff, explained why that capacity is needed despite the pit life findings:
First, even with longer lifetimes, as the stockpile ages, we will need to replace
considerable numbers of pits in stockpiled warheads. Second, even if pits were
to live forever, we will require substantial production capacity in order to
introduce, once feasibility is established, significant numbers of RRW warheads
into the stockpile by 2030. We should not assume that RRW could employ pit
reuse and still provide important efficiencies for stockpile and infrastructure
transformation. Finally, at significantly smaller stockpile levels than today, we
must anticipate that an adverse change in the geopolitical threat environment, or
a technical problem with warheads in the operationally-deployed force, could
require us to manufacture and deploy additional warheads on a relatively rapid
timescale.86
LEP supporters challenge each point. (1) The JASON study implies that NNSA
would not need to replace large numbers of pits of current warheads for many
decades. (2) LEP supporters recognize that the competing RRW designs use pits of
new design and would require pits of new manufacture, and that production of 50 pits
per year would hold deployment of RRWs to an extremely slow pace. However, they
see this reasoning as self-justifying: the assumption that RRW will be introduced
justifies a new pit facility, and a new pit facility makes it possible to introduce RRWs
at an acceptable pace. In the view of LEP supporters, LEP, especially if existing pits
are retained, permits the United States to delay a decision on RRW for decades. (3)
LEP supporters see this argument as circular. RRW permits a reduction in the
stockpile, while the possibility of a technical or geopolitical problem requires a larger
pit capacity to build more RRWs if needed. Instead, LEP supporters would retain
current warheads and maintain them with LEP and Stockpile Systems programs,
thereby avoiding the need for RRW and a new pit facility while hedging against
technical risks and geopolitical threats. They see these reductions in cost and risk as
outweighing any benefits that might arise from having fewer nondeployed warheads.
RRW supporters advance other reasons for a new pit facility. More capacity
would permit production of more than one pit type at a time, so NNSA could respond
to problems that require rebuilding pits out of the planned sequence and to threats
that require new-design pits. In contrast, it would be hard to manufacture several pit
types concurrently in PF-4, and if a problem were discovered in a pit type in the
stockpile, PF-4 might be unable to replace pits in time to prevent withdrawing some
86 Email to “possibly interested folks,” Nov. 29, 2006.

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CRS-35
weapon systems from deployment. Since PF-4 was completed in 1978, it might prove
less costly to build a new facility than to upgrade PF-4, as a recent example from
industry indicates.87 They doubt that PF-4 could accommodate increasingly stringent
safety and security requirements, and note that TA-55 has problems meeting current
standards.88 Pit production capacity is critical for RRW regardless of pit aging.
Since the first RRW will use new pits, production of 50 pits per year would make for
a slow deployment of RRWs; converting the stockpile to RRWs would take decades.
RRW supporters argue that using certified pits from retired warheads in RRWs
would permit faster introduction of RRWs whether NNSA uses PF-4 or CPC. LANL
saw pit reuse as desirable for RRW in theory because it would avoid most problems
and capacity limits of pit production and would save large sums. Nonetheless, it ruled
out pit reuse for missile warheads because existing pits could not accommodate all
the safety and use-control features in the RRW designs and because they would be
harder to certify than RRW pits. Pit reuse might, however, be possible for an RRW
bomb. Because bombs are larger and heavier than warheads, they permit a wider
range of design tradeoffs to improve margin, safety, and use control. Reusing pits
would make all the limited pit production capacity of PF-4 available for the first
RRW, rather than having to divide it between two warhead types.89
Regarding pit reuse, Thomas D’Agostino, Acting Administrator of NNSA, said,
And what we would like to do is examine those pits [currently in storage from
dismantled warheads], those small numbers of pits as potential pits that would
be used in future reliable replacement warhead concepts. For example, if we
were looking at providing reliable replacement concepts into a bomb, we would
look primarily to one of those pits that we already know has these features. And
assuming the shape is not a problem, then we would use that particular pit in that
system because it would have, again, offset further expense. A warhead on top
of a ballistic missile is a little bit different animal because of the constraints
associated with the size. And therefore, we had to kind of start from the ground
up on that particular system. And we didn't have enough of those old other pits.90
87 A Wall Street Journal article found that Toyota was able to achieve a considerably lower
cost per vehicle by building an automobile assembly plant from scratch, as compared to an
older General Motors plant. Lee Hawkins, Jr., and Norihiko Shirouzu, “A Tale of Two Auto
Plants — Pair of Texas Factories Show How Starting Fresh Gives Toyota an Edge over
GM,” Wall Street Journal, May 24, 2006, p. B1.
88 See, for example, U.S. Defense Nuclear Facilities Safety Board. “Memorandum for J.
Kent Fortenberry, Technical Director, from C.H. Keilers, Jr., subject Los Alamos Report
for Week Ending August 25, 2006,” Aug. 26, 2006, 1 p., at [http://www.dnfsb.gov/
pub_docs/lanl/wr_20060825_la.pdf].
89 Information provided by a senior Air Force official, interview with the author, Sept. 26,
2006.
90 Testimony of Thomas D’Agostino, Acting Under Secretary for Nuclear Security and
Administrator, NNSA, in U.S. Congress. House. Committee on Armed Services.
Subcommittee on Strategic Forces. Hearing on DOE’s Atomic Energy Programs, March 20,
2007.

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Some opponents of a new pit facility hold that PF-4’s capacity could be
increased beyond 50 per year. Some equipment could be removed, including that
used to fabricate plutonium-238 components for powering deep space probes.
Production equipment now in PF-4 was set up as a pilot project. Reconfiguring it
and adding new equipment could arguably support larger-scale production, though
pit production would likely have to be suspended to accommodate that effort.
Risks of RRW vs. Risks of LEP. Warheads put into the stockpile in the
past have had unanticipated problems. RRWs could have a similar experience, just
as there are recalls with cars and with laptop batteries. Significant Finding
Investigations (SFIs) illustrate issues that need to be addressed. Significant Findings
are defects discovered during surveillance of a warhead. If a defect is serious, an SFI
is launched by the laboratory responsible for that defect to determine its cause and
remedy.91 A review of SFIs completed in the mid-1990s showed that significant
defects were found one to two decades after the first production unit of a warhead
entered the stockpile. There are two conflicting interpretations. One is that the
defects arose because of aging, such as deterioration of plastics or explosives.
Another is that it may take two decades to find the final few percent of significant
defects in a warhead type. That is, some flaws may be there all along, and it takes
time and improved knowledge to discover them.
Congress may wish to inquire about each interpretation. Regarding RRW, why
deploy it now, after the bugs have been shaken out of current warheads? Why spend
large sums deploying a new warhead when it will arguably have reduced reliability
with respect to SFI-type issues that may take decades to identify? Might RRW,
which involves a new approach to design, introduce new risks and defects into the
stockpile? Regarding current warheads, what assurance can there be that SFIs and
surveillance have wrung out all the defects? Might serious defects be found in the
future because they develop with age or because advances in weapons science reveal
them? Congress might direct NNSA to update the 1996 SFI review to learn how
warhead aging and responses have developed in the past decade.
What actions might the 110th Congress take? The choice between LEP,
RRW, or some combination will set the course for U.S. nuclear weapons for decades
to come. However, the 110th Congress will not need to make a final decision. That
decision will come due if NNSA requests funds to begin full-scale development,
which by current plans is expected to be around FY2010. In the meantime, unless
it is prepared to reject RRW, Congress would be well served to gather additional
information to bound the many unknowns. Cost is important to the decision, yet
long-term cost projections are notoriously unreliable. There are technical
uncertainties, such as whether the winning RRW design can be turned into a
functioning warhead. The future Complex has yet to be determined, along with how
it might differ depending on whether the United States pursues LEP or RRW and
how it would handle a transition to an all-RRW stockpile. Stockpile numbers
decades out are unknowable, yet a Complex would spend money unnecessarily if
91 See U.S. Department of Energy. Office of Inspector General. Office of Audit Services.
Audit Report: Management of the Stockpile Surveillance Program’s Significant Findings
Investigations. DOE/IG-0535, December 2001, p. 1.

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sized too large and could not support requirements if sized too small. A commenter
noted that while claims are made that RRW is cheaper, safer, more reliable, etc., than
LEP, or vice versa, in many cases “no numbers exist to substantiate the claim. The
proponents of either approach, in many cases, while implying a measurable effect are
really saying ‘believe me.’”92 Congress may wish to use the time before it faces a
decision on full-scale development to gather data on technical and strategic issues,
cost, and Complex alternatives.
92 Personal communication, Sept. 7, 2006.

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CRS-38
Appendix A. Nuclear Weapons, Nuclear Weapons
Complex, and Stockpile Stewardship Program
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.93 The first stage, the “primary,” is an atomic bomb similar in principle
to the bomb dropped on Nagasaki. The primary provides the energy needed to trigger
the second stage, or “secondary.”
The primary has at its center a “pit,” a hollow core containing fissile material
(typically plutonium) and containment shells of other metals. It is surrounded by
chemical explosive shaped to generate a symmetrical inward-moving (implosion)
shock front. When the explosive is detonated, the implosion compresses the
plutonium, increasing its density so much that it becomes supercritical and can
sustain a runaway nuclear chain reaction. A neutron generator injects neutrons into
the plutonium. The neutrons drive this reaction by splitting (fissioning) plutonium
atoms, repeatedly doubling the number of neutrons released. But the chain reaction
can last only the briefest moment before the force of the nuclear explosion drives the
plutonium outward so that it becomes subcritical and can no longer support a chain
reaction. To increase the fraction of plutonium that is fissioned, boosting the yield
of the primary, another system injects “boost gas” — a mixture of deuterium and
tritium (isotopes of hydrogen) gases — into the pit before the explosive is detonated.
The intense heat and pressure of the fission chain reaction cause this gas to undergo
fusion. While the fusion reaction generates energy, its purpose is to generate a great
many neutrons and thus “boost” the fission chain reaction to a higher level.
A metal “radiation case” channels the energy of the primary to the secondary,
which contains fission and fusion fuel. The energy ignites the secondary, which
releases most of the energy of a nuclear explosion. The primary, radiation case, and
secondary comprise the “nuclear explosive package.” Thousands of “nonnuclear”
components are also needed to make the nuclear explosive package into a militarily
usable weapon, such as an arming, firing, and fuzing system, an outer case, and
electrical and physical connections linking a bomb to an airplane or a warhead to a
missile.
Nuclear weapons were designed, tested, and manufactured by the nuclear
weapons complex, which is composed of eight government-owned contractor-
operated sites: the Los Alamos National Laboratory (NM) and Lawrence Livermore
National Laboratory (CA), which design nuclear explosive packages; Sandia National
Laboratories (NM and CA), which designs nonnuclear components; Y-12 Plant (TN),
which produces uranium components and secondaries; Kansas City Plant (MO),
93 U.S. Department of Energy, Final Programmatic Environmental Impact Statement for
Stockpile Stewardship and Management, DOE/EIS-0236, Sept. 1996, summary volume, p.
S-4. That page contains further information on nuclear weapon design and operation.

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CRS-39
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. The
National Nuclear Security Administration (NNSA), a semiautonomous part of the
Department of Energy, manages the nuclear weapons complex and program.
NNSA maintains nuclear weapons and associated expertise through the
Stockpile Stewardship Program (SSP), which Congress created in the FY1994
National Defense Authorization Act (P.L. 103-160, section 3138). The legislation
specified that the goal of SSP is “to ensure the preservation of the core intellectual
and technical competencies of the United States in nuclear weapons” through
“advanced computational capabilities,” “above-ground experiments” (experiments
not requiring nuclear testing), and construction of large experimental facilities. SSP
has three main elements. Directed Stockpile Work involves work directly on nuclear
weapons in the stockpile, such as monitoring their condition, maintaining them
through refurbishment and modifications, R&D in support of specific warheads, and
dismantlement. It includes the Life Extension Program and the RRW program.
Campaigns provide focused scientific and engineering expertise in support of
Directed Stockpile Work, in such areas as pit manufacturing and certification,
computation, and study of the properties of materials. Readiness in Technical Base
and Facilities funds infrastructure and operations at the nuclear weapons complex
sites. While the legislation did not specify that SSP was not to involve nuclear
testing, that goal seems clear from the history, and has become a goal of the program.
NNSA does not rule out the possible need for testing, such as if a problem were to
emerge in a warhead type that could not be remedied in any other way.

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Appendix B. Congressional Language Setting Goals
Congress has set forth many goals for the RRW program.
[1] That program originated as a funded activity in the conference report on the
FY2005 Consolidated Appropriations Act, when conferees stated that $9.0 million
“is made available for the Reliable Replacement Warhead program to improve the
reliability, longevity, and certifiability of existing weapons and their components.”94
This was RRW’s Washington debut; NNSA had not requested funds for it, and the
relevant congressional reports had not mentioned it.
[2] P.L.
109-163, the FY2006 National Defense Authorization Act, Section
3111, sets seven requirements for the program. (The text includes quotation marks
because the requirements add a new Section 4204a, Reliable Replacement Warhead
Program, to the Atomic Energy Defense Act, Division D of P.L. 107-314.)
(a) Program Required. — The Secretary of Energy shall carry out a program, to
be known as the Reliable Replacement Warhead program, which will have the
following objectives:
(1) To increase the reliability, safety, and security of the United States nuclear
weapons stockpile.
(2) To further reduce the likelihood of the resumption of underground nuclear
weapons testing.
(3) To remain consistent with basic design parameters by including, to the
maximum extent feasible and consistent with the objective specified in
paragraph (2), components that are well understood or are certifiable
without the need to resume underground nuclear weapons testing.
(4) To ensure that the nuclear weapons infrastructure can respond to unforeseen
problems, to include the ability to produce replacement warheads that are
safer to manufacture, more cost-effective to produce, and less costly to
maintain than existing warheads.
(5) To achieve reductions in the future size of the nuclear weapons stockpile
based on increased reliability of the reliable replacement warheads.
(6) To use the design, certification, and production expertise resident in the
nuclear complex to develop reliable replacement components to fulfill
current mission requirements of the existing stockpile.
(7) To serve as a complement to, and potentially a more cost-effective and
reliable long-term replacement for, the current Stockpile Life Extension
Programs.
[3] For FY2006, the House Armed Services Committee set forth many goals
for RRW. Those not in the preceding text include the following:
The committee understands that by designing and replacing components and
warheads in our existing arsenal, the nuclear weapons complex can take full
advantage of modern design techniques, more environmentally safe materials,
94 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, 108th Cong.,
2nd sess., H.Rept. 108-792, 2004, p. 951.

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and efficient manufacturing processes in a way that can make our arsenal more
reliable, safe, and secure. ... the committee encourages the Department of
Defense and the Department of Energy to focus initial Reliable Replacement
Warhead efforts on replacement warheads for Submarine Launched Ballistic
Missiles. ... A second objective of this program is to further reduce the likelihood
of the resumption of nuclear testing by increasing warhead design margin and
manufacturability. ... [A sixth goal is] ensuring that the human capital aspect is
not neglected. The nuclear complex is rapidly losing its design and production
expertise, a concern highlighted by several studies in the past decade. The
Reliable Replacement Warhead program will help train and sustain the weapons
designers and engineers whose expertise is essential in ensuring the stockpile
remains, reliable, safe and secure into the future.95
[4] The Senate Armed Services Committee set goals in its FY2006 report:
The committee understands from the testimony of the Administrator of the
National Nuclear Security Administration (NNSA) that the goals of this program
are: (1) to increase the security and reliability of the nuclear weapons stockpile;
(2) to develop replacement components for nuclear warheads that can be more
easily manufactured with more readily available and more environmentally
benign materials; (3) to develop replacements that can be introduced into the
stockpile with assured high confidence regarding their effect on warhead safety
and reliability; (4) to develop these replacements on a schedule that would reduce
the possibility that the United States would ever be faced with the need to
conduct a nuclear test in order to diagnose or remedy a reliability problem in the
current stockpile; (5) to reduce infrastructure costs needed to support the
stockpile, while increasing the responsiveness of that infrastructure; and (6) to
increase confidence in the stockpile to a level such that significant, additional
reductions in numbers of non-deployed `hedge’ warheads can be made.
The committee supports these goals and this modest investment [$9.4 million]
in feasibility studies ... with the goal of substantially increasing the safety,
security, and reliability of the nuclear weapons stockpile and with the ultimate
objective of achieving the smallest stockpile consistent with our nation’s
security.96
[5] Most House Armed Services Committee Democrats presented their goals
for the program in a statement of additional views in the committee’s FY2006 report:
In our opinion, the RRW program is only worth[y] of support if it:
• Truly reduces or eliminates altogether the need for nuclear testing;
• Leads to dramatic reductions in the nuclear arsenal, including complete
dismantlement of the weapons and safe disposal of fissile components;
• Does not introduce new mission or new weapon requirements, particularly for
tactical military purposes;
95 U.S. Congress. House. Committee on Armed Services. National Defense Authorization
Act for Fiscal Year 2006. H.Rept. 109-89, on H.R. 1815, 109th Cong., 1st sess., 2005, p. 464.
96 U.S. Congress. Senate. Committee on Armed Services. National Defense Authorization
Act for Fiscal Year 2006. S.Rept. 109-69 to accompany S. 1042, 109th Cong., 1st sess., 2005,
p. 482.

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• Reduces the reliance of the U.S. on nuclear weapons and deemphasizes the military
utility of nuclear weapons;
• Significantly reduces the cost of maintaining our nuclear weapon complex, to include
avoiding the need to build a modern pit facility;
• Increases nuclear security and decreases the risk of unauthorized or accidental launch
and/or detonation; and
• Leads to ratification and entry into force of the Comprehensive Test Ban Treaty.97
[6] The House Appropriations Committee, in its report on FY2006 energy and
water development appropriations, listed various requirements for RRW:
The Committee is supportive of the Administration taking an accelerated
approach to implement a new nuclear weapons paradigm that ensures the
continued moratorium on nuclear testing and results in a dramatically smaller
nuclear weapons stockpile in the near future. The RRW weapon will be designed
for ease of manufacturing, maintenance, dismantlement, and certification without
nuclear testing, allowing the NNSA to transition the weapons complex away
from a large, expensive Cold War relic into a smaller, more efficient modern
complex. A more reliable replacement warhead will allow long-term savings by
phasing out the multiple redundant Cold War warhead designs that require
maintaining multiple obsolete production technologies to maintain the older
warheads. The Committee’s qualified endorsement of the RRW initiative is
based on the assumption that a replacement weapon will be designed only as a
re-engineered and remanufactured warhead for an existing weapon system in the
stockpile. The Committee does not endorse the RRW concept as the beginning
of a new production program intended to produce new warhead designs or
produce new weapons for any military mission beyond the current deterrent
requirements. The Committee’s support of the RRW concept is contingent on the
intent of the program being solely to meet the current military characteristics and
requirements of the existing stockpile.98
[7] The Senate Appropriations Committee’s report on FY2006 energy and
water development appropriations stated:
NNSA is undertaking the RRW Program to understand if warhead design
constraints imposed on Cold War systems (e.g. high yield to weight ratios that
have typically driven `tight’ performance margins in nuclear design) are relaxed,
could replacement components for existing stockpile weapons be more easily
manufactured with more readily available and more environmentally benign
materials, and whose safety and reliability could be assured with high
confidence, without nuclear testing. This effort does not call into question the
safety or reliability of the current stockpile but acknowledges the long-term
sustainability of the legacy stockpile will be difficult. Implementation of RRW
should also result in reduced life-cycle costs for supporting the stockpile.99
97 U.S. Congress. House. Committee on Armed Services. National Defense Authorization
Act for Fiscal Year 2006. H.Rept. 109-89, on H.R. 1815, 109th Cong., 1st sess., 2005, p. 512.
98 U.S. Congress. House. Committee on Appropriations. Energy and Water Development
Appropriations Bill, 2006. H.Rept. 109-86 to accompany H.R. 2419, 109th Cong., 1st sess.,
2005, p. 130.
99 U.S. Congress. Senate. Committee on Appropriations. Energy and Water Appropriations
(continued...)

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[8] The FY2006 energy and water conference report stated:
The conferees reiterate the direction provided in fiscal year 2005 that any
weapon design work done under the RRW program must stay within the military
requirements of the existing deployed stockpile and any new weapon design must
stay within the design parameters validated by past nuclear tests. The conferees
expect the NNSA to build on the success of science-based stockpile stewardship
to improve manufacturing practices, lower costs and increase performance
margins, to support the Administration’s decision to significantly reduce the size
of the U.S. nuclear stockpile.100
The FY2007 committee reports were released after the preliminary RRW
designs were completed, and did not add requirements for RRW design.
99 (...continued)
Bill, 2006. S.Rept. 109-84 to accompany H.R. 2419, 109th Cong., 1st sess., 2005, p. 155.
100 U.S. Congress. Committee of Conference. Making Appropriations for Energy and Water
Development for the Fiscal Year Ending September 30, 2006, and for Other Purposes.
H.Rept. 109-275 to accompany H.R. 2419, 109th Cong., 1st sess., 2005, p. 159.

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Appendix C. Abbreviations
CCRD
Competing candidate RRW design
CHE
Conventional high explosive
CPC
Consolidated Plutonium Center
DNFSB
Defense Nuclear Facilities Safety Board
DOD
Department of Defense
DOE
Department of Energy
ESD
Electrostatic discharge
ICBM
Intercontinental ballistic missile
IHE
Insensitive high explosive
LANL
Los Alamos National Laboratory
LEP
Life Extension Program
LLNL
Lawrence Livermore National Laboratory
NEP
Nuclear explosive package
NNSA
National Nuclear Security Administration
RB
Reentry Body (Navy term; same as RV)
RRW
Reliable Replacement Warhead
RV
Reentry Vehicle (Air Force term; same as RB)
SLBM
Submarine-launched ballistic missile
SSP
Stockpile Stewardship Program

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