GAO-07-243R Annual Assessment

United States Government Accountability Office

Washington, DC 20548 

February 2, 2007 

The Honorable Ellen O. Tauscher 

Chairman 

The Honorable Terry Everett 

Ranking Minority Member 

Subcommittee on Strategic Forces 

Committee on Armed Services 

House of Representatives 

Subject: Nuclear Weapons: Annual Assessment of the Safety, Performance, and 

Reliability of the Nation’s Stockpile 

In 1992, the United States began a unilateral moratorium on the underground testing 

of nuclear weapons. Prior to the moratorium, underground nuclear testing was a 

critical component for evaluating and certifying nuclear warheads.1

 In 1993, the 

Department of Energy (DOE), at the direction of the President and the Congress, 

established the Stockpile Stewardship Program to increase understanding of the 

basic phenomena associated with nuclear weapons, provide better predictive 

understanding of the safety and reliability of weapons, and ensure a strong scientific 

and technical basis for future United States nuclear weapons policy objectives.2

 The 

National Nuclear Security Administration (NNSA), a separately organized agency 

within DOE, is now responsible for carrying out the Stockpile Stewardship Program 

through a nuclear weapons complex that comprises three nuclear weapons design 

laboratories (weapons laboratories), four production plants, and the Nevada Test 

Site. 

In 1995, the President established an annual stockpile assessment and reporting 

requirement to help ensure that the nation’s nuclear weapons remained safe and 

reliable without underground nuclear testing. This decision was made in the context 

of negotiating a multilateral Comprehensive Test Ban Treaty to ban all nuclear 

weapons test explosions. As a condition or safeguard under which the United States 

would enter into such a test ban, the President established “Safeguard F”—an 

understanding that if the Secretaries of Energy and Defense informed the President 

that conducting an underground nuclear test was critical to maintaining confidence in 

a weapon’s safety or reliability, the President, in consultation with the Congress, 

 

1

Certification is the process through which the weapons laboratories establish that a particular nuclear 

warhead or bomb meets its designated military operational specifications. 2

The National Defense Authorization Act for Fiscal Year 1994, Pub. L. No. 103-160, § 3135 (1993), 

directed DOE to establish the Stockpile Stewardship Program. 
would be prepared to withdraw from the treaty. While the President submitted 

Safeguard F along with the Comprehensive Test Ban Treaty to the Senate for 

ratification in 1997, the Senate voted to reject the treaty in 1999. However, the United 

States continues to maintain a moratorium on underground nuclear testing as a 

matter of national policy. 

Subsequently, the Congress enacted into law the requirement for an annual stockpile 

assessment (annual assessment) process in section 3141 of the National Defense 

Authorization Act for Fiscal Year 2003.3

 Specifically, section 3141 requires that the 

Secretaries of Energy and Defense submit a package of reports on the results of their 

annual assessment to the President by March 1 of each year. The President must 

forward the reports to the Congress by March 15. These reports are prepared 

individually by the directors of the three DOE weapons laboratories—Los Alamos 

National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and 

Sandia National Laboratories (SNL)—and by the Commander of the U.S. Strategic 

Command (USSTRATCOM), who is responsible for targeting nuclear weapons within 

the Department of Defense (DOD). The reports provide each official’s assessment of 

the safety, reliability, and performance of each weapon type in the nuclear stockpile. 

In addition, the Commander of USSTRATCOM assesses the military effectiveness of 

the stockpile. In particular, the reports include an assessment about whether it is 

necessary to conduct an underground nuclear test to resolve any identified issues. 

The Secretaries of Energy and Defense are required to submit these reports unaltered 

to the President, along with the conclusions the Secretaries have reached as to the 

safety, reliability, performance, and military effectiveness of the nuclear stockpile. 

The Nuclear Weapons Council (NWC), a joint DOD/DOE organization that 

coordinates nuclear weapons activities between the two departments, supports the 

two Secretaries in fulfilling their responsibility to inform the President if a return to 

underground nuclear testing is required to address any issues identified with the 

stockpile.4

 In this context, you asked us to describe the processes that DOE and DOD 

have established for fulfilling the requirements of the annual assessment. 

To determine the process that DOE and DOD have established to fulfill the annual 

assessment requirements, we reviewed the major reports and briefings generated 

during the annual assessment cycles for 2005 and 2006, including the reports 

generated by the weapons laboratories and USSTRATCOM. We also interviewed 

DOE and DOD officials, including representatives from NNSA, each weapons 

laboratory, USSTRATCOM, the NWC, the Air Force, the Navy, and the U.S. Nuclear 

Command and Control System Support Staff. In addition, we interviewed former 

National Security Council staff and staff associated with the House and Senate 

Committees on Armed Services to obtain the perspective of the end users of the 

annual assessment reports. We conducted our review from April 2006 to December 

2006 in accordance with generally accepted government auditing standards. 

 3

Pub. L. No. 107-314, § 3141 (2002). 4

The National Defense Authorization Act for Fiscal Year 1987, Pub. L. No. 99-661, § 3137 (1986), 

established the Nuclear Weapons Council. See 10 U.S.C. § 179. 

Page 2 GAO-07-243R Annual Assessment
Summary 

To satisfy the requirements of section 3141 of the National Defense Authorization Act 

for Fiscal Year 2003, DOD and DOE have established an annual assessment process 

that reaches conclusions and makes judgments about the U.S. nuclear stockpile and, 

in particular, whether it is necessary to conduct an underground nuclear test to 

resolve any questions about a particular weapon type. The annual assessment 

process takes about 14 months to complete—during which time the nuclear weapons 

community collaborates on technical issues affecting the safety, reliability, 

performance, and military effectiveness of the stockpile—and produces seven 

different types of reports. The annual assessment process culminates in the “Report 

on Stockpile Assessments” prepared by the NWC, which includes an executive 

summary, a joint letter signed by the Secretaries of Energy and Defense, and 

unaltered copies of the weapons laboratory director reports and the Commander of 

USSTRATCOM report. 

The directors of the nuclear weapons laboratories base their reports on the technical 

work of their laboratories, which is derived from ongoing work associated with 

NNSA’s Stockpile Stewardship Program, as well as feedback they receive from 

independent teams of experts from all three of the weapons laboratories. The 

Commander of USSTRATCOM bases his report on the advice of a technical advisory 

group, which holds an annual conference bringing together all of the organizations 

involved in the annual assessment, and additional operational information provided 

by USSTRATCOM and the military services. The NWC, supported by warheadspecific technical groups, pulls together the information from DOE and DOD. The 

NWC then produces an executive summary of all of the reports and prepares a joint 

letter from the Secretaries of Energy and Defense to the President of the United

States, which is forwarded to the Congress. While the principal purpose of annual 

assessment is to provide analysis of and judgments about the safety, reliability, 

performance, and military effectiveness of the nuclear stockpile, the process would 

not be used as a vehicle for notifying decision makers about an immediate need to 

conduct a nuclear test. According to agency and congressional officials, if an issue 

with a weapon were to arise that required a nuclear test to resolve, the Secretaries of 

Energy and Defense, the President, and the Congress would be notified immediately 

and outside of the context of the annual assessment process. 

We provided a draft of this report to NNSA and DOD for their review and comment. 

Overall, NNSA stated that it generally agreed with the findings of the draft report. 

NNSA also provided technical comments, which we incorporated into the report as 

appropriate. DOD provided oral comments of a technical nature, which we 

incorporated into the report as appropriate. 

Background 

The U.S. nuclear weapons stockpile consists of nine weapon types. (See table 1.) 

These weapons include gravity bombs deliverable by dual-capable fighter aircraft and 

long-range bombers; cruise missiles deliverable by aircraft and submarines; 

submarine-launched ballistic missiles; and intercontinental ballistic missiles. 

Page 3 GAO-07-243R Annual Assessment
 

Table 1: Current U.S. Nuclear Weapon Types 

Warhead or 

bomb type

Description Delivery system Laboratory Military service

B61-3/4/10 Tactical bomb F-15, F-16, Tornado LANL / SNL Air Force 

B61-7/11 Strategic bomb B-52, B-2 LANL / SNL Air Force 

W62 ICBM warheada Minuteman III ICBM LLNL / SNL Air Force 

W76 SLBM warheadb Trident D5 missile, 

ballistic-missile 

submarine 

LANL / SNL Navy 

W78 ICBM warhead Minuteman III ICBM LANL / SNL Air Force 

W80-0 

W80-1 

TLAM/Nc

ALCM, ACMd

Attack submarine 

B-52 

LLNL / SNL 

LLNL / SNL 

Navy 

Air Force 

B83-1 Strategic bomb B-52, B2 LLNL / SNL Air Force 

W87 ICBM warhead Minuteman III ICBM LLNL / SNL Air Force 

W88 SLBM warhead Trident D5 missile, 

ballistic-missile 

submarine 

LANL / SNL Navy 

Source: NWC. 

Note: As of 2005, responsibility for the W80-0/1 was transferred from LANL to LLNL. The 

W87 is in the process of transitioning from the Peacekeeper missile to the Minuteman III 

missile. 

a

 ICBM = Intercontinental Ballistic Missile. b

 SLBM = Submarine-Launched Ballistic Missile. c

 TLAM/N = Tomahawk Land-Attack Missile/Nuclear. d

 ALCM = Air-Launched Cruise Missile; ACM = Advanced Cruise Missile. 

In the context of the annual assessment process, the terms “warhead,” “weapon,” and 

“delivery system” have different technical meanings. 

• A nuclear warhead is composed of a nuclear explosive package, which includes 

the components that produce nuclear energy of a militarily significant yield and a 

set of supporting nonnuclear components. Depending on the specific weapon 

type, the supporting nonnuclear components control the use, arming, and firing of 

the nuclear explosive package. 

• A nuclear weapon includes the warhead and certain weapon-specific 

components, such as fuzes, batteries, and reentry vehicles and bodies (in the case 

of a ballistic missile) that configure the warhead for DOD use in a missile or as a 

bomb. 

• A delivery system is the military vehicle—ballistic or cruise missile, airplane, or 

submarine—by which a nuclear weapon could be delivered to its intended target. 

Both DOE and DOD have responsibilities for nuclear weapons. DOE is responsible 

for nuclear warheads and for nuclear bombs in their entirety (including components 

such as parachutes). For reentry vehicles and reentry bodies, DOD is responsible for 

Page 4 GAO-07-243R Annual Assessment
components that arm the weapon and provide authorization for its use. Specific 

organization responsibilities are as follows: 

• Two DOE weapons laboratories (LANL and LLNL) design the nuclear explosive 

packages and conduct scientific research and development to better understand 

nuclear weapons phenomena. The DOE engineering laboratory (SNL) has 

principal responsibility for the research, design, and development of nonnuclear 

warhead components; integration of these components with LANL and LLNL; and 

overall warhead systems integration with DOD.5

• DOE’s NNSA oversees the management and operation of the weapons 

laboratories, the Nevada Test Site, and four production plants—the Pantex Plant 

in Texas, the Y-12 National Security Complex in Tennessee, the Kansas City Plant 

in Missouri, and a portion of the Savannah River Site in South Carolina. These 

plants manufacture nuclear warhead components, assemble nuclear weapons, 

and disassemble and inspect nuclear weapons in preparation for surveillance 

testing and other activities. The Nevada Test Site maintains the capability to 

conduct underground nuclear testing and also conducts experiments involving 

nuclear material and high explosives. 

• The military services—the Air Force and the Navy, in the case of the current 

stockpile—develop the operational specifications for nuclear weapons. These 

specifications are defined in two documents: (1) the military characteristics 

document, which describes the required operational performance characteristics 

(e.g., yield) for a particular warhead type, and (2) the stockpile-to-target sequence 

document, which describes the normal and abnormal environments a warhead 

type is expected to encounter throughout its lifetime. In addition, the military 

services operate nuclear weapons storage sites within the continental United 

States and are responsible for the safety, security, survivability, movement, 

storage, and maintenance of all nuclear weapons in those storage areas. 

• USSTRATCOM, which was established as a unified combatant command in 1992, 

has primary responsibility for the use of strategic nuclear forces, including 

targeting nuclear weapons and preparing the U.S. strategic nuclear war plan. 

Unified combatant commands are responsible for accomplishing the multiservice 

missions assigned to them by the Secretary of Defense. Starting in 2002, the 

mission of USSTRATCOM expanded and now includes responsibilities associated 

with global strike planning and execution; integrating global ballistic missile 

defense; overseeing intelligence, surveillance, and reconnaissance; global 

command and control; DOD information operations; and DOD’s efforts to combat 

weapons of mass destruction. 

• The Strategic Advisory Group Stockpile Assessment Team (SAGSAT) is part of a 

USSTRATCOM advisory committee and provides technical expertise to the 

USSTRATCOM Commander on nuclear weapons issues. Specifically, SAGSAT

 5

In addition to these activities, LANL maintains an interim production capability for limited quantities

of plutonium components and manufactures nuclear weapon detonators. SNL also manufactures

neutron generators. 

Page 5 GAO-07-243R Annual Assessment
supports the Commander by (1) conducting an annual conference on nuclear 

weapons stockpile assessment that considers all nuclear weapons in the 

stockpile; (2) reporting on trends regarding confidence in the reliability, safety, 

and surety of the nuclear weapons stockpile and whether nuclear testing is 

required; and (3) advising on performance and surety issues. The members of the 

SAGSAT are recognized experts in the nuclear weapons field and are generally 

retired employees of the national laboratories and military services or have held 

positions with major defense contractors. 

• The NWC is a joint DOD/DOE organization established by the Congress in 1987 to 

facilitate high-level cooperation and coordination between the two departments 

as they fulfill their dual responsibilities for securing, maintaining, and sustaining 

the U.S. nuclear weapons stockpile. The NWC is chaired by the Under Secretary 

of Defense for Acquisition, Technology and Logistics. Other members include the 

Vice Chairman of the Joint Chiefs of Staff, the Under Secretary of Energy for 

Nuclear Security (NNSA Administrator), the Under Secretary of Defense for 

Policy, and the Commander of USSTRATCOM. 

• A Project Officers Group (POG) is a joint DOD/DOE group that is chartered by the 

NWC at the beginning of a weapon development program.6

 For each weapon type, 

a POG provides the technical forum for coordinating activities related to the 

development, sustainment, operational effectiveness, and overall management of 

the weapon, including the weapon’s compatibility with its delivery system. Each 

POG is led by a lead project officer (LPO) who reports to the NWC through the 

lead cognizant military service (Air Force or Navy). POG membership is specific 

to the weapon for which it is responsible but generally includes organizations 

within DOE and DOD—such as NNSA, the weapons laboratories, combatant 

commands, and the military services—that expend resources on the weapon. 

President Clinton established the requirement for an annual assessment and 

reporting process in a 1995 statement that accompanied his announcement of support 

for a Comprehensive Test Ban Treaty: “...I am today directing the establishment of a 

new annual reporting and certification requirement that will ensure that our nuclear 

weapons remain safe and reliable under a comprehensive test ban.” While the 

President’s original statement uses the term “certification,” the nuclear weapons 

community currently refers to this process as “assessment.” The reason for this 

distinction, according to NNSA and laboratory officials, is that the term “certification” 

has a specific, technical meaning that is separate from that intended by the annual 

assessment process. Specifically, certification is the process through which the 

weapons laboratory directors establish that a particular nuclear warhead or bomb 

meets its designated military characteristics, stockpile-to-target sequence, and 

“interface requirements” (compatibility with its delivery system). According to NNSA 

and laboratory officials, once a warhead is certified, it remains certified until it is 

either decertified or retired. As a result, annual assessment is not an annual 

“recertification” of the stockpile; rather, according to officials from NNSA and the 

weapons laboratories, it is an assessment of whether each warhead type still meets 

the same standards as it did when it was originally certified. 

 6

Almost all of the current POGs were originally chartered by the Military Liaison Committee, the 

predecessor of the NWC. 

Page 6 GAO-07-243R Annual Assessment
Following the President’s 1995 statement, the NWC issued guidance in 1996 to 

formalize the processes used by DOE and DOD to meet the annual assessment and 

reporting requirement. Subsequently, in 2001, President Bush reaffirmed that the 

annual assessment and reporting process would continue. Finally, the National 

Defense Authorization Act for Fiscal Year 2003 enacted the requirements for annual 

assessments into law. Specifically, section 3141 of the act requires the director of 

each weapons laboratory and the Commander of USSTRATCOM to make an annual 

assessment of the safety, reliability, and performance of each weapon type in the 

nuclear stockpile. The Commander of USSTRATCOM is also required to make an 

annual assessment of the military effectiveness of the stockpile. In addition, these 

officials are required to issue individual reports on their assessments to the 

Secretaries of Energy and Defense, and to the NWC, by December 1 of each year. 

These reports must include an assessment as to whether it is necessary to conduct an 

underground nuclear test to resolve any issues identified in the reports. By March 1 

of each year, the Secretaries of Energy and Defense are required to submit these 

reports unaltered to the President, along with the conclusions that the Secretaries 

have reached as to the safety, reliability, performance, and military effectiveness of 

the nuclear stockpile. Finally, the President is required to forward these reports, 

along with any comments the President considers appropriate, to the Congress no 

later than March 15 of each year. 

Section 3141 of the act also expanded the requirements for annual assessment 

beyond the original process established in 1996. More specifically, it required 

• the weapons laboratory directors and the Commander of USSTRATCOM to 

include in their reports (1) an identification of specific underground nuclear tests 

that, while not necessary, might have value in resolving any identified issues, and 

(2) a determination of the readiness of the United States to conduct an 

underground nuclear test (where one is deemed to be necessary or valuable), 

• the weapons laboratory directors to include in their reports (1) a summary of 

findings from “red teams,” made up of experts from all three weapons 

laboratories, who have reviewed technical laboratory information and subjected it 

to challenge; (2) a concise statement regarding the adequacy of science-based 

tools and methods used in making the assessment; and (3) a concise statement 

regarding the adequacy of tools and methods employed by the manufacturing 

infrastructure to identify and fix any problems addressed by the assessment, and 

• the Commander of USSTRATCOM to include in his report (1) a discussion of the 

relative merits of other nuclear weapon types or compensatory measures that 

could be taken should any deficiency be identified and (2) identification of any 

matter having an adverse effect on the Commander’s ability to accurately address 

the issues covered by the assessment. 

Page 7 GAO-07-243R Annual Assessment
Events over the past several years have served to intensify concern about how the 

United States maintains its nuclear deterrent. Specifically, 

• The 2001 Nuclear Posture Review stated, among other things, that Cold War 

practices related to nuclear weapons planning were obsolete, and few changes 

had been made to the size or composition of the nation’s nuclear forces. 

Furthermore, the review found that there had been underinvestment in the 

nuclear weapons complex, particularly the production sites. The review called 

for, among other things, the development of a “responsive infrastructure” that 

would be sized to meet the needs of a smaller nuclear deterrent while having the 

capability of responding to future strategic challenges. 

• The 2002 Moscow Treaty between the United States and Russia set a goal of 

reducing the number of operationally deployed strategic U.S. nuclear warheads to 

between 1,700 and 2,200 by 2012. However, a significant number of existing 

warheads will be kept in reserve as augmentation warheads to address potential 

technical contingencies with the existing stockpile or geopolitical changes. 

• In recent congressional testimony, the Secretary of Energy and the Administrator 

of NNSA emphasized that while they believe stockpile stewardship is working, the 

current Cold War legacy stockpile is wrong for the long term, and the current 

nuclear weapons infrastructure is not responsive to unanticipated events or 

emerging threats. 

• NNSA and DOD created the Reliable Replacement Warhead program to study a 

new approach for providing a credible nuclear warhead deterrent over the long 

term.7

 The Reliable Replacement Warhead program would redesign weapon 

components to be easier to manufacture, maintain, dismantle, and certify without 

nuclear testing, potentially allowing NNSA to transition to a smaller and more 

efficient weapons complex. A design competition between LANL and LLNL was 

originally scheduled to be completed in November 2006. While NNSA and DOD 

have not yet announced the selection of a preferred design, the two departments 

have determined that the RRW is feasible. 

• Finally, in 2006, NNSA offered a proposal to address long-standing problems with 

the condition and responsiveness of the nuclear production facilities. Under its 

plan—Complex 2030: A Preferred Infrastructure Planning Scenario for the 

Nuclear Weapons Complex—NNSA proposed to build a new, consolidated 

plutonium center at a yet-to-be determined location that would replace the interim 

plutonium production capability at LANL. A key responsibility of the plutonium 

center would be to manufacture components for a Reliable Replacement 

Warhead-based stockpile. In addition, NNSA proposed modernizing the remaining 

production capabilities at their existing locations, including the Y-12 National 

Security Complex, Savannah River Site, and Pantex Plant. NNSA also proposed 

 7

The conference report accompanying DOE’s fiscal year 2005 appropriations act provided that funds 

appropriated were available for the Reliable Replacement Warhead Program. H.R. Rep. No. 108-792,

Div. C, at 951 (2004), accompanying the fiscal year 2005 Consolidated Appropriations Act, Pub. L. No. 

108-447. 

Page 8 GAO-07-243R Annual Assessment
eventually removing all weapons-grade material from the three weapons 

laboratories. 

The Annual Assessment Process Results in a Package of Reports That Make

Conclusions and Judgments about the Nuclear Stockpile 

The annual assessment process results in a series of high-level reports that make 

conclusions and judgments about the safety, performance, reliability, and military 

effectiveness of the weapons in the nuclear stockpile and whether there is a technical 

issue that requires resolution through underground nuclear testing. These high-level 

reports are underpinned by technical reports that capture ongoing work on the 

stockpile, specifically activities associated with DOE’s Stockpile Stewardship 

Program and other DOD surveillance activities. In total, the following seven types of 

reports are produced during a single annual assessment cycle: 

• Weapons Laboratory Annual Assessment Reports (AARs): AARs are prepared for 

each weapon type by the technical staff of the weapons laboratory responsible for 

the nuclear explosive package (LANL or LLNL) and their engineering counterpart 

at SNL. Each AAR contains technical information concerning the potential need 

for underground nuclear testing and whether each warhead type meets its 

required military characteristics, such as warhead yield, throughout its stockpileto-target sequence. 

• Weapons Laboratory Red Team Reports: A red team at each weapons laboratory 

issues a report to the laboratory director that assesses the technical information 

contained in the laboratory’s AARs and the potential need for underground 

nuclear testing. 

• Weapons Laboratory Director Reports: Each laboratory director submits an 

independent assessment report of the safety, performance, and reliability of the

nuclear stockpile to the NWC and the Secretaries of Energy and Defense by 

December 1 of each year. 

• SAGSAT Report: The SAGSAT prepares a report for the USSTRATCOM 

Commander that provides the technical underpinning for the Commander’s 

assessment of the stockpile. This report expresses the SAGSAT’s confidence as to 

whether each warhead type will perform as designed and makes 

recommendations for USSTRATCOM action. 

• Commander of USSTRATCOM Report: The Commander of USSTRATCOM 

submits an independent assessment report of the safety, performance, reliability 

and military effectiveness of the nuclear stockpile to the NWC and the Secretaries 

of Energy and Defense by December 1 of each year. 

• POG Reports: Each POG issues a technical annual assessment report to the NWC 

on the warhead type for which it is responsible. These reports are based largely 

on the weapons laboratories’ AARs but also include additional information on 

military-service specific issues, including the results of surveillance testing 

performed by DOD and its contractors, operational issues such as deployment 

Page 9 GAO-07-243R Annual Assessment
numbers, and logistical issues such as the status of work on weapons being done 

at military installations. 

• Report on Stockpile Assessments: The NWC prepares a report package, known as 

the “Report on Stockpile Assessments,” on behalf of the Secretaries of Energy and 

Defense. The package includes an executive summary, a joint letter signed by 

both Secretaries, and unaltered copies of the weapons laboratory director reports 

and the Commander of USSTRATCOM report. This package is conveyed to the 

President by March 1 and forwarded to the Congress by March 15 of each year. 

Each annual assessment cycle takes approximately 14 months to complete. Figure 1 

illustrates the time frames during which each type of annual assessment report was 

developed and completed during the 2005 cycle. Specifically, technical analysis 

conducted by the laboratories began in December 2004 and was completed in July 

2005. Subsequently, the laboratory directors and Commander of USSTRATCOM 

completed their high-level reports by the middle of October, in advance of their 

December 1 statutory deadline. The NWC prepared the executive summary between 

the end of September 2005 and the end of February 2006.

Page 10 GAO-07-243R Annual Assessment
Figure 1: 2005 Annual Assessment Reporting Time Line

Note: The red team reports are not listed separately but are used by the laboratory directors in

completing their reports.

The Weapons Laboratories’ and Laboratory Directors’ Reports Are Based on Ongoing 

Stockpile Stewardship Program Activities

According to laboratory officials, the information provided in the AARs—the 

technical basis for the annual assessment process—is derived from ongoing activities 

associated with NNSA’s Stockpile Stewardship Program. Specifically, the AARs

focus on the following three areas: 

• Surveillance: A key component of the Stockpile Stewardship Program is annual 

surveillance testing, in which active stockpile weapons are randomly selected,

disassembled, inspected, and tested—either in laboratory tests or in flight tests—

to identify any problems that might affect a weapon’s safety or reliability. 

Problems identified during surveillance testing that may warrant further testing 

and analysis result in the creation of a “significant finding investigation” to 

determine the problems’ cause, extent, and effect on the performance, safety, and 

reliability of the stockpile. As part of the Stockpile Stewardship Program, NNSA 

tracks surveillance results through quarterly reports on significant finding 

investigations and other surveillance reports. Each AAR (1) summarizes the 

Page 11 GAO-07-243R Annual Assessment
status of surveillance testing at the three laboratories; (2) details any backlog 

there might be in surveillance testing; and (3) describes the effect of surveillance 

results, significant finding investigations, or surveillance backlogs on weapon 

performance, safety, or reliability. In recent years, AARs have called attention to 

the importance of surveillance testing as weapons in the stockpile are aging 

beyond their original design lives. Further, AARs have highlighted limitations at 

the production complex, particularly at the Pantex Plant, that have contributed to 

surveillance backlogs.8

• Performance: The annual assessment seeks to determine whether each warhead 

type still meets the same standards it did when it was originally certified. A key 

standard is whether the performance of the nuclear explosive package would 

meet requirements for generating militarily significant yield should the weapon be 

used. To support this determination, LANL and LLNL use a “quantification of 

margins and uncertainties” (QMU) methodology, which focuses on creating a 

common “watch list” of factors that are the most critical to the operation and 

performance of a nuclear weapon.9

 QMU seeks to quantify (1) how close each 

critical factor is to the point at which it would fail to perform as designed and (2) 

the uncertainty that exists in calculating the margin, in order to ensure that the 

margin is sufficiently larger than the uncertainty. The laboratories’ use of QMU 

depends significantly on their ability to simulate the explosion of a nuclear 

weapon. Toward this end, the weapons laboratories rely on NNSA’s Advanced 

Simulation and Computing program, which supports stockpile stewardship by 

providing computer simulation capabilities to predict weapons’ performance, 

safety, and reliability. Computer models are validated against the historic data 

collected during previous underground nuclear tests and are constantly improved 

and updated as new data becomes available from surveillance testing, material 

properties testing, and other physics experiments. Based on the use of QMU, 

computer simulations, and experimental data, AARs report a warhead’s expected 

yield, factors influencing the expected yield, and the extent to which there is 

uncertainty in the expected yield.

• Reliability: All nuclear weapons are originally certified to meet a key military 

characteristic known as weapon reliability. DOE defines weapon reliability as 

“the probability of achieving the specified yield, at the target, across the Stockpileto-Target Sequence of environments, throughout the weapon’s lifetime, assuming 

proper inputs.” According to laboratory officials, LANL and LLNL use QMU to 

support the reliability assessment of each weapon type’s nuclear explosive 

package, while SNL uses statistical data and QMU-based methodologies to predict 

the reliability of nonnuclear components. SNL then combines these probabilities 

to come up with an overall reliability calculation for each warhead or bomb type. 

NNSA issues a separate, semiannual report on weapon reliability and provides it 

 8

For information on the status of surveillance backlogs, see DOE Office of Inspector General, Followup Audit on Stockpile Surveillance Testing, October 2006, DOE/IG-0744. 9

For more information on QMU, see GAO, Nuclear Weapons: NNSA Needs to Refine and More 

Effectively Manage Its New Approach for Assessing and Certifying Nuclear Weapons, GAO-06-261

(Washington, D.C.: Feb. 3, 2006).

Page 12 GAO-07-243R Annual Assessment
to USSTRATCOM for use in war planning. The laboratories’ AARs republish the 

most recent reliability calculations in the context of annual assessment.10

To oversee the development of the AARs and to facilitate key annual assessment 

deliverables, each laboratory relies on an annual assessment coordinator and key 

technical staff. Laboratory coordinators develop schedules for the circulation of 

between three and five drafts of each AAR. Laboratory program managers for each 

weapon type are responsible for the technical content of each AAR, and dozens of 

other scientific and engineering staff at each laboratory participate in the 

development and review of AARs. Drafts of the AARs are reviewed by officials from 

the other weapons laboratories, the relevant POGs, and NNSA. In addition, one 

laboratory coordinator told us that he looks at cross-cutting issues in the AARs to 

ensure that they are being consistently and completely addressed. Beginning in the 

2006 annual assessment cycle, laboratory coordinators from LANL and LLNL 

collaborated to organize an additional level of peer review by bringing both 

laboratory directors together to receive technical annual assessment briefings from 

their staffs upon completion of the AARs. 

NNSA oversees the weapons laboratories’ annual assessment reporting activities 

through the use of an annual assessment coordinator. The NNSA annual assessment 

coordinator said that officials throughout NNSA review drafts of the laboratories’ 

AARs and provide comments to the laboratories on the accuracy of these reports. In 

addition, NNSA has issued formal business and operating guidance11 for the conduct 

and oversight of the annual assessment process that contains milestones for key 

laboratory deliverables and requirements for the format and organization of 

laboratory AARs. At the beginning of each annual assessment cycle, the NNSA 

annual assessment coordinator meets with the laboratory coordinators to agree on 

the major milestones and key deliverables for the year and to highlight areas for 

improvement from the previous year. NNSA also issues formal tasking letters and an 

execution plan to each of the laboratories for the annual assessment cycle. The 

letters state that AARs should not become advocacy platforms for specific upgrades 

or enhancements, or for specific facilities or technology developments. In addition, 

the plan states that, aside from meeting statutory requirements, the format and 

organization of the laboratory directors’ reports are left entirely up to each director. 

Red teams, comprised of experts from all three of the weapons laboratories, also 

develop reports and provide additional technical input for each laboratory director’s 

consideration. The use of red teams is mandated by section 3141, which requires the 

red teams to challenge the technical information provided in the laboratories’ AARs 

and to provide independent analysis to each laboratory director. According to 

laboratory officials, red team members’ activities are not constrained. For example, 

they can interview laboratory employees without notifying laboratory management in 

advance. In addition, some red team members are retired laboratory employees, 

which is seen as enhancing their independence. However, laboratory officials said 

that red teams do not have separate budgets and do not have resources to perform 

 10In commenting on our draft report, NNSA officials stated that the laboratory AARs also focus on 

safety. Specifically, NNSA stated that the annual assessment seeks to determine whether each

warhead type still meets the same safety requirements as it did when originally certified. 11NNSA Policy Letter: BOP-10.001 dated July 14, 2005 and annual tasking letters.

Page 13 GAO-07-243R Annual Assessment
their own experiments or gather their own data. Instead, they are expected to pose 

questions to those responsible for the technical information in the AARs and make 

recommendations to the laboratory director. A LANL official said that the findings of 

LANL’s red team are shared with its laboratory director and senior laboratory 

weapons managers. However, at LLNL and SNL, the red teams’ findings are shared 

more broadly with laboratory staff. 

Finally, the laboratory directors rely on the AARs, the red teams’ findings, and 

additional technical assessments provided by laboratory experts and managers to 

write their own report, which reflects their individual assessment of the safety, 

performance, and reliability of the weapons in the nuclear stockpile. In particular, 

laboratory directors consult with laboratory technical staff to assess nuclear test 

readiness, the adequacy of the tools and methods employed by the production 

complex, and the adequacy of science-based tools and methods. Details of each of 

these areas of assessment are as follows: 

• Test readiness: According to laboratory officials, each laboratory has technical 

staff with specific responsibilities related to the Test Readiness program, which is 

managed by NNSA and focuses on the ability of the Nevada Test Site to conduct 

an underground nuclear test, should a decision be made to resume underground 

testing. Laboratory staff work on an ongoing basis with their counterparts at the 

Nevada Test Site and, for annual assessment, brief the laboratories on the status 

of issues related to test readiness. In addition, laboratory directors identify highpriority nuclear tests—tests that would provide significant data to resolve 

identified issues—in their annual assessment reports, and this information is 

provided to NNSA and Nevada Test Site officials for their use in the Test 

Readiness program. In a separate, biannual report to the Congress, NNSA also 

provides data on essential workforce skills, capabilities, and infrastructure 

requirements to support test readiness.12

• Adequacy of tools and methods employed by the production complex: Laboratory 

officials said that laboratory employees work on-site at the production plants and 

provide regular updates to the laboratory directors on the status of the production 

complex. These officials noted that laboratory directors are not obligated to 

assess the overall adequacy or capability of the manufacturing complex; rather, 

the laboratory directors focus on the extent to which manufacturing tools and 

methods are sufficient to allow them to assess the safety, performance, and 

reliability of the stockpile. NNSA officials said that limitations at the production 

complex, particularly at the Pantex Plant, have contributed to surveillance 

backlogs, which affect the laboratories’ ability to make a complete assessment. 

However, because the existing weapon types have been in the stockpile for 

decades, laboratory officials expressed confidence in their understanding of 

production processes and the extent to which production capabilities or 

inadequacies affect their ability to assess the stockpile. 

• Adequacy of science-based tools and methods: Laboratory officials said that to 

assess the adequacy of science-based tools and methods, laboratory directors 

 12H.R. Rep. No. 106-945 §3192, accompanying the fiscal year 2001 National Defense Authorization Act, 

Pub. L. No. 106-398. 

Page 14 GAO-07-243R Annual Assessment
consider whether the laboratories have the capabilities to continue to effectively 

and efficiently assess the safety, performance, and reliability of the stockpile. For 

example, LANL officials said that impediments to addressing significant finding 

investigations may call attention to areas where the laboratories’ science-based 

tools and methods need improvement. In addition, LLNL officials said that they 

rely heavily on the QMU methodology to assess the adequacy of their computer 

modeling efforts. However, laboratory officials said that meeting the standard for 

adequacy does not require laboratories to have capabilities to address every 

question about the stockpile that may arise. Other laboratory officials 

acknowledged that the laboratory directors’ conclusions about the adequacy of 

science-based tools and methods do not always agree and that, while tools and 

methods may currently be adequate, this assessment could change in the future. 

The Commander of USSTRATCOM’s Report Is Based Primarily on the Advice of a 

Technical Advisory Group

According to USSTRATCOM and SAGSAT officials, the SAGSAT fulfills its primary 

mission—to provide technical expertise to the USSTRATCOM Commander—by 

conducting an assessment of all nuclear weapons in the stockpile and reporting on 

this assessment to the Commander. The SAGSAT holds an annual conference to 

gather information from all of the parties involved in annual assessment, including 

the weapons laboratories, the POGs, NNSA, and DOD. The conference is typically 

held each year in June and lasts approximately 1 week. In advance of the conference, 

the SAGSAT issues guidance to each of the conference attendees describing specific 

topics of interest on which the SAGSAT and Commander would like to briefed. The 

guidance that SAGSAT issued for the 2006 annual assessment cycle directed the 

weapons laboratories and the POGs to provide warhead system-specific briefings that 

focused on safety and security, nuclear explosive package performance, operational 

testing plans and results, and the projected health of the warhead. In addition, this 

guidance directed 

• NNSA to address the overall status of the production complex and plans for 

addressing shortfalls in current stockpile support activities, such as surveillance 

testing; 

• LANL and LLNL to provide information on their efforts to advance the QMU 

methodology and on the status of a study on the lifetime of plutonium; 

• SNL to present its approach to using the QMU methodology; and 

• Air Force and Navy to present an overview of the operational readiness and 

reliability of delivery systems to the extent that delivery system performance may 

have a direct effect on the performance of a nuclear warhead; a SAGSAT official 

told us that the SAGSAT has requested this briefing from the military services 

each year since 2004. 

After its conference, the SAGSAT prepares its own report for the Commander that 

covers all of the warhead types. The report (1) makes qualitative statements about 

the SAGSAT’s confidence in each warhead or bomb’s safety, reliability, and 

performance; (2) provides the SAGSAT’s opinion as to whether a return to 

underground testing is warranted for each warhead/bomb type; (3) calls attention to 

areas of disagreement with the laboratories or NNSA; (4) focuses on areas that could 

Page 15 GAO-07-243R Annual Assessment
affect operational decisions; and (5) makes recommendations for USSTRATCOM 

action. The SAGSAT report is forwarded to the DOD and DOE, and SAGSAT 

members also provide this information in an annual briefing to the NWC’s Standing 

and Safety Committee—a working-level group that meets monthly to develop, 

coordinate, and approve most actions before they are reviewed and approved by the 

full NWC. 

According to USSTRATCOM officials, the Commander of USSTRATCOM bases his 

assessment report largely on the advice of the SAGSAT. However, the Commander 

also relies on other operational information he receives from USSTRATCOM staff and 

the military services. For example, one group within USSTRATCOM determines the 

number of nuclear weapons the command needs each year, which affects decisions 

made about each weapon type. In addition, USSTRATCOM staff serve as voting

members of the POGs. In this capacity, USSTRATCOM staff participate in and inform 

the Commander about operations and logistics decisions. Finally, USSTRATCOM 

sets requirements for flight testing, an important part of surveillance testing in which 

mock weapons are flown in realistic environments. The results of flight tests are 

reflected in the Commander’s report and affect his ability to express confidence in 

the military effectiveness of weapon types in the absence of underground nuclear 

testing. 

As the operator of nuclear weapons, USSTRATCOM uses information on overall 

weapon system reliability, which is calculated by the military services, in war 

planning. To this end, the USSTRATCOM Commander’s annual assessment is distinct 

from the laboratory directors’ assessments in that the Commander provides an 

operational perspective in his report. The Commander’s report makes observations 

about the immediate and longer-term needs for underground nuclear testing and 

states whether his confidence in the reliability of each warhead type has increased, 

decreased, or remained unchanged. He also discusses the extent to which he 

believes the laboratories and military services are addressing known issues in the 

stockpile, calls attention to issues that could be addressed if additional programs 

were authorized or funded, and discusses operational alternatives to address any 

identified problems. 

The POGs Produce Assessments for the NWC Based on Their Review of Ongoing 

DOD and DOE Nuclear Weapon Activities 

Each POG develops its own annual assessment report for the NWC, reflecting the 

combined technical input of the POG members, including officials from NNSA, the 

weapons laboratories, and the military services. The information contained in the 

POG reports is derived from ongoing DOD and DOE nuclear weapon activities that 

the POGs regularly monitor. POGs conduct their work through subgroups, whose 

members have technical expertise in the areas germane to the subgroup’s 

responsibility. For example, members of POG subgroups on safety and reliability are 

responsible for ensuring that their warheads meet all joint DOD/DOE safety and 

reliability requirements, including military characteristics and stockpile-to-target 

sequences. In addition, the LPOs of each POG are required to provide an annual 

briefing to the NWC’s Standing and Safety Committee on the status of each weapon 

type, including any issues identified within the context of the annual assessment. All 

Page 16 GAO-07-243R Annual Assessment
reports and briefings issued by the POGs are reviewed and approved by the 

applicable military service before being submitted to the NWC.13

The NWC Synthesizes and Summarizes the Other Reports to Produce the “Report on 

Stockpile Assessments”

The NWC uses the POG reports, the weapons laboratories’ AARs, the laboratory 

directors’ reports, and the USSTRATCOM Commander’s report to produce the 

“Report on Stockpile Assessments” for the President and the Congress on behalf of 

the Secretaries of Energy and Defense. The “Report on Stockpile Assessments” is a 

package of reports, including the unaltered reports from the laboratory directors and 

the Commander of USSTRATCOM, NWC’s executive summary, and a joint letter from 

the Secretaries of Energy and Defense, which provides the overall assessment of the 

stockpile and states whether any official has concluded that there is a technical 

requirement to perform an underground nuclear test. The executive summary and 

joint letter are reviewed and agreed upon at three levels of the NWC over the course 

of several months: (1) the Action Officer level, which includes military officers at the 

Air Force Colonel or Navy Captain level and their civilian equivalents, (2) the 

Standing and Safety Committee, and (3) the full NWC. In these successive reviews, 

information is brought up to a higher level, and policy concerns are addressed. NNSA 

and laboratory officials told us the Secretary of Energy receives an extensive briefing 

from senior NNSA officials and the three weapons laboratory directors before signing 

the joint letter. USSTRATCOM officials told us the Secretary of Defense does not 

receive a formal briefing but rather relies upon staff in the Office of the Secretary of 

Defense to inform him of any issues before he signs the joint letter.

NNSA and laboratory officials have questioned whether the NWC’s executive 

summary provides additional value to the annual assessment process, particularly 

because it takes over 5 months to complete. For example, NNSA officials said that 

they brief the Secretary of Energy on annual assessment several months before the 

NWC’s executive summary is complete. Further, a laboratory official said the 

executive summary focuses too much on restating technical information rather than 

providing the context in which the technical information should be received. 

However, congressional staff and a former National Security Council official with 

whom we spoke—end users of the annual assessment reports—told us they found 

the executive summary useful for identifying issues and comparing high-level 

conclusions from year to year. For example, the 2005 NWC executive summary 

(submitted in March 2006) highlighted differences in opinion between (1) the LANL 

and LLNL directors as to the adequacy of science-based tools and methods and (2) 

the laboratory directors and the Commander of USSTRATCOM on long-term needs 

for nuclear testing. Furthermore, NWC and congressional staff said that a lot of time 

is spent coordinating between the Offices of the Secretary of Energy and the 

Secretary of Defense to get their signatures on the “Report on Stockpile 

Assessments” package. As a result, according to these officials, the NWC would still 

 13In the Navy, the chief officer of the Strategic Systems Programs Office reviews Navy-led POG reports 

and briefings. In the Air Force, the chief officers of the Nuclear Weapons Counterproliferation Agency 

and its parent organization, the Strategic Security Directorate, review Air Force-led POG reports and 

briefings. 

Page 17 GAO-07-243R Annual Assessment
take a considerable amount of time to complete its activities even if it did not write 

an executive summary.

The Annual Assessment Provides a Forum through Which the Nuclear Weapons 

Community Collaborates on Technical Issues

While individual members of the nuclear weapons community are responsible for 

developing their own reports as part of the annual assessment, the annual assessment 

process has broad participation from organizations that are responsible for the 

stockpile and provides a forum through which the nuclear weapons community 

collaborates on technical issues affecting the safety, reliability, and performance of 

the stockpile. For example, officials from DOD and DOE stated that the SAGSAT 

provides a unique function within the annual assessment process. Its annual 

conference is the only occasion that brings together all of the organizations involved 

in annual assessment—including the weapons laboratories, the POGs, NNSA, DOD, 

and the military services—at one time to discuss each weapon at a technical level. 

One DOD official said the collaborative aspect of the annual assessment process is 

unique and is a benefit completely separate from the reports or other written 

products. Collaboration during the annual assessment process can also lead to the 

resolution of disagreements. For example, after concerns over DOD support for 

weapons flight tests were raised, the NWC tasked NNSA and USSTRATCOM to 

determine whether the agencies could support changes to flight test requirements. 

Figure 2 illustrates the collaborative aspect of annual assessment process. 

Figure 2: Interagency Collaboration During Annual Assessment

Page 18 GAO-07-243R Annual Assessment
The Annual Assessment Process Is Not a Vehicle for Reporting Immediate Issues

Regarding Nuclear Testing

While the principal purpose of annual assessment is to provide an analysis of the 

safety, reliability, performance, and military effectiveness of the nuclear stockpile, 

the process would not be used as a vehicle for notifying decision makers about an 

immediate need to conduct a nuclear test. As stated earlier, the annual assessment 

process takes 14 months to complete. According to DOE and DOD officials, if an 

issue with a weapon were to arise that required an underground nuclear test to 

resolve, the Secretaries of Energy and Defense and the President would be notified 

immediately and outside of the context of the annual assessment process. DOD and 

NNSA officials told us that the annual assessment reports are intended to provide 

information on the safety and performance of the stockpile within a particular time 

frame and are not a good tool for reporting on problems that need to be addressed 

immediately. A senior congressional official agreed with this characterization and 

said that if an immediate issue arose for which nuclear testing was considered 

necessary to resolve, it would be appropriate to notify executive and congressional 

decision makers directly. 

Finally, according to laboratory officials, there are several options the nuclear 

weapons community could explore before conducting an underground nuclear test. 

These options include component replacements, refurbishments, selective 

retirements, and approving exceptions to military characteristic or stockpile-to-target 

sequence requirements. Laboratory and congressional officials said all of these 

options would be rigorously considered before recommending an underground 

nuclear test. However, a DOD official also said that if an issue were to surface 

suddenly that required an underground nuclear test, the length of time it would take 

to prepare for an underground test—which could be 18 months or more—would 

probably exceed the length of each annual assessment cycle. As a result, the annual 

assessment reports would ultimately reflect a decision to resume underground 

nuclear testing. 

Agency Comments and Our Evaluation 

We provided a draft of this report to NNSA and DOD for their review and comment. 

Overall, NNSA stated that it generally agreed with the findings of the draft report. 

The complete text of NNSA’s comments on our draft report is presented in enclosure 

I. NNSA also provided technical comments, which we incorporated into the report as 

appropriate. DOD provided oral comments of a technical nature, which we 

incorporated into the report as appropriate. 

- - - - - 

As agreed with your offices, unless you publicly announce the contents of this report 

earlier, we plan no further distribution until 30 days from the report date. At that 

time, we will send copies of this report to the Secretaries of Energy and Defense, the 

Administrator of NNSA, and appropriate congressional committees. We also will 

make copies available to others upon request. In addition, this report will be 

available at no charge on the GAO Web site at http://www.gao.gov. 

Page 19 GAO-07-243R Annual Assessment
If you or your staff have any questions about this report, please contact me at (202) 

512-3841 or aloisee@gao.gov. Contact points for our Offices of Congressional 

Relations and Public Affairs may be found on the last page of this report. Key 

contributions to this report were made by James Noel, Assistant Director; Allison 

Bawden; Jason Holliday; John Delicath; and Doreen Feldman. 

Gene Aloise 

Director, Natural Resources 

 and Environment 

Enclosure 

Page 20 GAO-07-243R Annual Assessment
Enclosure I 

Comments from the National Nuclear Security Administration 

(360695)

Page 21 GAO-07-243R Annual Assessment
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