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Former IAEA Director-General
Security at U.S. Weapons Laboratories

Another Look at Iran's Nuclear Capability Timelines

Cover of INCBC Report by the International Institute of Strategic Studies By Alfred Nurja The International Institute for Strategic Studies (IISS) released this month a substantial analysis of Iran's nuclear, chemical and biological capabilities. The report's detailed break-out scenarios allow readers to finally make some sense of the various and conflicting timelines that have circulated in recent years about when and how Iran could produce a nuclear bomb if that is what it chose to pursue. More importantly, the nuclear section of the IISS publication also makes a number of observations that...

Kyl Mischaracterizes ACA on Missile Defense

By Tom Collina The Arms Control Association often finds itself at odds with Senate Republican Minority Whip Jon Kyl (Ariz.). After all, Sen. Kyl led opposition to the Comprehensive Test Ban Treaty in 1999 and to New START last year, both of which ACA strongly supports. Even so, ACA prides itself on cultivating a civil, fact-based debate on policy issues, and we expect the same of others. We were thus disappointed to read Sen. Kyl's Jan. 31, 2011 floor speech in which he mischaracterized ACA's position. In his prepared remarks, Sen. Kyl stated that the Senate's Resolution of Ratification,...

The State of the Union and Nuclear Policy

Image Source: White House By Rob Golan-Vilella Last night, President Barack Obama delivered his annual State of the Union address to a joint session of Congress. As expected, the speech focused heavily on domestic and economic policy. With unemployment still over 9% and the national discussion still largely overshadowed by the fallout from the recent shootings in Tucson, it was unsurprising that foreign policy issues received little mention. Most of the comparatively brief section on foreign policy was devoted to terrorism and America's ongoing wars in Afghanistan and Iraq. Still, Obama...

U.S.-China Cooperation Demonstrates Need for Congress to Fully Fund Nuclear Security

By Rob Golan-Vilella As Chinese President Hu Jintao visits Washington this week, the United States and China have reached an agreement that will improve nuclear security in China. The NNSA announced yesterday that the two nations have signed a memorandum of understanding that will establish a nuclear security "Center of Excellence" in China. According to the NNSA: The Center will serve as a forum for exchanging technical information, sharing best practices, developing training courses, and promoting technical collaborations that will enhance nuclear security in China and throughout Asia. This...

GAO: Nuclear Security Agenda Needs Details

The Obama administration’s nuclear security agenda is short on details concerning its "overall estimated cost, time frame, and scope of planned work," the Government Accountability Office said.

Robert Golan-Vilella and Daniel Horner

The Obama administration’s nuclear security agenda is short on details concerning its “overall estimated cost, time frame, and scope of planned work,” the Government Accountability Office (GAO) said in a report released Dec. 15. In the report, consisting of a public summary of the classified September version, the GAO also assessed the nuclear security work performed by the Department of Energy’s National Nuclear Security Administration (NNSA) and found that its progress was uneven across programs and countries.

The GAO reported that the National Security Council (NSC) has approved a document that serves as a government-wide strategy for achieving President Barack Obama’s goal of securing all vulnerable nuclear materials within four years. (See ACT, May 2009.) That document lays out the main actions that the U.S. government will take toward this end and defines the role of each agency involved in the effort, according to the GAO. However, the GAO said that “this interagency strategy lacks specific details concerning how the initiative will be implemented.”

According to the GAO, the “NSC does not consider the 4-year time frame for securing nuclear materials worldwide a hard and fast deadline.” NSC officials said they saw it instead as a “forcing function” to drive U.S. nuclear nonproliferation programs and mobilize greater international support on the issue of nuclear security, the report says.

The GAO recommended that the NSC lead and coordinate “the development of a comprehensive plan for implementing” Obama’s four-year initiative. That plan should identify “the specific foreign countries, sites, and facilities where materials have been determined to be poorly secured”; the agencies responsible for addressing each location; potential challenges and the steps needed to overcome them; and the time frames and costs associated with the goal. According to the report, NSC officials provided no written comments on this recommendation but said they believed development of such a plan could take years.

Mixed Progress in NNSA Programs

The report focused in detail on the contributions of the NNSA to the nuclear security initiative. The NNSA “was the only agency to have developed a formal written plan with specific details regarding how it intends to contribute to the 4-year nuclear material security goal,” the GAO said.

The NNSA received the highest marks for its Material Protection, Control, and Accounting (MPC&A) activities in Russia. Through this program, which works to conduct security upgrades at nuclear facilities, the NNSA has improved security at 110 Russian nuclear warhead and material sites, the GAO said. However, the GAO noted that the MPC&A program is due to expire on Jan. 1, 2013, and transfer full responsibility for its activities to Russia. The report argued that the NNSA would be unlikely to meet this deadline and recommended that the NNSA and Congress take steps to prepare for extending the program past 2012.

Other NNSA programs in Russia have achieved more limited success, the GAO said. The Materials Consolidation and Conversion (MCC) program was created in 1999 with the goal of moving highly enriched uranium (HEU) from 50 buildings and five sites by 2010; it “has achieved removal of all HEU from only 1 site and 25 buildings,” the report said.

Likewise, the Global Threat Reduction Initiative (GTRI), which includes an effort to convert or shut down Russian HEU reactors, has made little progress toward that end, the GAO said. According to the report, the GTRI plans to convert or shut down 71 HEU-fueled research reactors and related facilities in Russia by 2020. To date, Russia has shut down three HEU facilities and committed to shutting down five others, the GAO said.

Under an agreement signed Dec. 7, Russia and the United States agreed to conduct feasibility studies on the conversion of six reactors in Russia. According to the GAO report, previous estimates had said the accord would be completed “in early fiscal year 2010,” which began in October 2009.

“NNSA officials told us that any agreement to conduct these studies would not constitute an official Russian decision to convert or undertake activities toward conversion,” the GAO said. In a Dec. 30 e-mail to Arms Control Today, NNSA spokesman Damien LaVera said, “While [the Dec. 7 agreement] does not commit Russia to convert those reactors, we think this is an important step forward and a demonstration of our joint commitment to minimizing the use of HEU wherever possible.”

Beyond Russia

The GAO report cites several notable successes in GTRI efforts to remove weapons-usable material from nearly two dozen countries. Following Ukraine’s commitment at the April 2010 nuclear security summit in Washington to get rid of all of its HEU by 2012, in May the GTRI facilitated the removal of “more than a third of Ukraine’s HEU inventory” to Russia, according to the report.

The report notes the NNSA’s completion of a contract with South Africa for the return of U.S.-origin spent HEU fuel to the United States. According to LaVera, the contract, signed in August 2010, covers 5.8 kilograms of U.S.-origin HEU spent fuel. The material is scheduled to be returned to the United States in the first half of 2011, he said. That will mark the removal of all U.S.-origin HEU spent fuel from South Africa, he said.

Another U.S.-South African effort cited by the GAO concerns the production of the medical isotope molybdenum-99 (Mo-99) from low-enriched uranium (LEU) by the South African Nuclear Energy Corporation (Necsa). Until now, large-scale producers of the isotope, which is used to detect diseases and study organ structure, have used HEU. However, in a Dec. 6 press release, the NNSA announced the arrival in the United States of the first shipment of LEU-based Mo-99 approved by the U.S. Food and Drug Administration for use by U.S. patients. The United States has no Mo-99 production facilities. In the Dec. 30 e-mail, LaVera said Necsa and the NNSA had been working together for years on this issue and that after the April summit, the NNSA provided $25 million to support Necsa’s conversion efforts.

The GAO report also examined nuclear security cooperation with China and India, which the GAO said has been much more limited in its scope and results.


And the Winners of the 2010 "Arms Control Persons of the Year" Title Are ...

... Kazakhstan's Deputy Foreign Minister Kairat Umarov, National Nuclear Security Administration (NNSA) Administrator Tom D'Agostino, and their international partners "for securing material containing 10 metric tons of highly enriched uranium and three metric tons of weapons-grade plutonium, which is enough to make about 775 nuclear weapons. The operation is the largest of its kind and is an example of the international cooperation envisaged by the leaders attending the April 2010 Nuclear Security Summit in Washington, D.C." The winners received the highest number votes in ACA's online poll...

GAO Finds Problems in Tritium Production

Technical problems have prevented the Department of Energy’s National Nuclear Security Administration (NNSA) from producing as much tritium as it planned, the Government Accountability Office (GAO) said in a report released last month.

Although the NNSA currently is meeting the tritium requirements for the U.S. nuclear weapons stockpile, “its ability to do so in the future is in doubt,” said the GAO, the investigative arm of Congress.

Daniel Horner

Technical problems have prevented the Department of Energy’s National Nuclear Security Administration (NNSA) from producing as much tritium as it planned, the Government Accountability Office (GAO) said in a report released last month.

Although the NNSA currently is meeting the tritium requirements for the U.S. nuclear weapons stockpile, “its ability to do so in the future is in doubt,” said the GAO, the investigative arm of Congress.

Tritium is a radioactive gas used to boost the explosive power of nuclear weapons. Because it decays at a rate of 5.5 percent a year, supplies of it have to be replenished periodically from either retired weapons or new production.

According to the GAO, “Although the number of nuclear weapons in the U.S. stockpile is decreasing, these reductions are unlikely to result in a significant decrease of tritium requirements and will not eliminate the need for a reliable source of new tritium.”

The tritium for the U.S. arsenal is being produced by irradiating special fuel rods, known as Tritium-Producing Burnable Absorber Rods (TPBARs), in Watts Bar-1, a nuclear power reactor owned and operated by the Tennessee Valley Authority (TVA), a federal corporation. Tritium is then extracted from the TPBARs in a facility at the Energy Department’s Savannah River Site in South Carolina.

TPBARs were first irradiated at Watts Bar in 2003.

The technical problem that is the focus of the GAO report is tritium “permeation” from the TPBARs into reactor coolant water at a rate that is higher than expected. The NNSA has noted the problem in budget documents, but in an interview last year, the manager of the NNSA’s Savannah River Site office said the main issue was the potential impact on reactor operation rather than on tritium production. (See ACT, June 2009.)

Because regulations for nuclear power reactors set a ceiling on the amount of tritium that can be released into the coolant, the TVA has limited the number of TPBARs loaded into Watts Bar-1, the GAO said. As the GAO noted, the Energy Department’s agreement with the TVA allows it to use two additional TVA reactors, Sequoyah-1 and -2, for tritium production.

However, as the NNSA put it in a letter to GAO commenting on a draft of the report, “Both TVA and NNSA would experience programmatic and operational benefits from keeping tritium production in one reactor, and will be working to achieve this goal. Nevertheless, NNSA does have this backup plan that can meet mission requirements with existing technologies and assets.”

The GAO said, “While we are encouraged that NNSA and TVA are working together to increase the number of TPBARs being irradiated, continued uncertainty about NNSA’s and TVA’s ability to irradiate additional TPBARs in a single reactor while not exceeding limits on the amount of tritium released into the environment raises doubts about the program’s ability to provide a reliable supply and predictable quantities of tritium over time.”

From the beginning of the program, some tritium permeation had been expected, NNSA spokeswoman Jennifer Wagner said in an Oct. 29 e-mail to Arms Control Today. The higher-than-expected permeation was initially observed in the summer of 2004, she said.


Building on the Success of the Nuclear Security Summit



This week's unprecedented Nuclear Security Summit successfully focused international attention and action on a critical issue which has been absent from national agendas for too long: securing material that terrorists could acquire and use in nuclear weapons.


Statement by Daryl G. Kimball, Executive Director of the Arms Control Association and Peter Crail, ACA Nonproliferation Analyst

April 13, 2010

(Washington, D.C.) This week's unprecedented Nuclear Security Summit successfully focused international attention and action on a critical issue which has been absent from national agendas for too long: securing material that terrorists could acquire and use in nuclear weapons. The threat of nuclear terrorism has been called the ultimate preventable catastrophe because the math is simple: if terrorists or those who might aid them are unable to acquire the material, they have zero chances of building a weapon. The task, therefore, is to accelerate efforts to secure the material where it exists, dispose of it where possible, and limit its further production.

By gathering a representative group of global leaders, the summit was also able to point out that this risk of nuclear terrorism is a shared one and is not just a threat to the United States. The use of a nuclear weapon by terrorists anywhere would have an impact across the globe. And as dozens of countries around the world contain material that could be used in nuclear weapons, it is also a shared responsibility.

The summit communiqué and detailed work plan is therefore an important first step in carrying out the shared responsibility to secure nuclear material (specifically highly enriched uranium and separated plutonium) in a cooperative manner and on an accelerated, four-year timetable. Additionally, the specific national commitments and efforts by states such as Chile, Mexico, and Ukraine to abandon their civilian-use HEU have delivered clear and practical gains by taking such dangerous material out of circulation.

While it is vital that states cooperate to secure existing stockpiles of nuclear weapons-usable material, it is equally important that they devote renewed attention and energy to halting the production of even more weapons-useable material, which only increases the risk of nuclear weapons use and nuclear terrorism. For over the past 15 years, France, Russia, the United Kingdom, and the United States, have declared that they no longer produce fissile material for weapons, and China is also believed to have halted such production around the same time.

In addition to its leadership in calling for international cooperation to secure nuclear weapons-usable material, the United States should also seek a commitment from countries such as India and Pakistan that continue to produce fissile material for weapons to halt such production, pending the negotiation of a global, verifiable Fissile Material Cut-off Treaty.

Similarly, the United States should strongly discourage states such as France and Japan from continuing to separate plutonium as part of their spent fuel reprocessing program, and the United States should also urge states considering reprocessing to refrain from doing so. Indeed, as the future host of the 2012 nuclear security summit, South Korea could make a significant contribution towards the summit goal by announcing that it would not pursue any form of reprocessing.

The Nuclear Security Summit has been a success that will help advance President Obama's broader efforts to address threats posed by nuclear weapons. We call upon the U.S. Congress to fully support programs aimed at enhancing nuclear security around the globe and combatting illicit nuclear trafficking. The follow-up on the Nuclear Security Summit Work Plan will be crucial to securing all nuclear material in four years, and the United States and all of the participants must remain engaged to make that goal a reality.

A Different Kind of Complex: The Future of U.S. Nuclear Weapons and the Nuclear Weapons Enterprise

In an October 28 speech to the Carnegie Endowment for International Peace entitled "Nuclear Weapons and Deterrence in the 21st Century," Secretary of Defense Robert Gates noted the continued importance of U.S. nuclear weapons for deterring possible opponents and for reassuring allies that they do not need to develop their own weapons. He argued that, to carry out these responsibilities, a Reliable Replacement Warhead (RRW) as well as a modernized complex for nuclear weapons that would allow the building of new weapons without nuclear explosion testing are needed. (Continue)

Richard L. Garwin

In an October 28 speech to the Carnegie Endowment for International Peace entitled "Nuclear Weapons and Deterrence in the 21st Century," Secretary of Defense Robert Gates noted the continued importance of U.S. nuclear weapons for deterring possible opponents and for reassuring allies that they do not need to develop their own weapons. He argued that, to carry out these responsibilities, a Reliable Replacement Warhead (RRW) as well as a modernized complex for nuclear weapons that would allow the building of new weapons without nuclear explosion testing are needed.

I have great admiration for Secretary Gates and suggested months ago that he should be urged to continue to serve in an Obama administration. His dismissal of the Air Force secretary and chief of staff over negligence in management of nuclear weapons (see page 44) was a rare and appropriate action. In regard to the RRW program and other nuclear weapons questions, however, the leadership of the Department of Defense is ill served by its advisers on nuclear warheads, who appear not to be conveying to the secretary the judgment of the nuclear weapons labs that the plutonium pit of each U.S. nuclear weapon is expected to last at least 85 years.

Gates' recent remarks echo a 2007 report of the Departments of Defense, Energy, and State that suggested that delays in the replacement warhead program would "raise the prospect of having to return to underground nuclear testing to certify existing weapons."[1]

The chairman and ranking member on the House Appropriations energy and water subcommittee wrote in August 2007 that, "It is irresponsible for the administration to make such an assertion." They correctly noted that that "there is no record of congressional testimony or reports sent to Congress by the Administration claiming...that a resumption of testing to verify the performance of warheads would be a necessity."[2]

Congress ultimately rejected the administration's proposal for an ambitious, multidecade plan to build replacement warheads and a nuclear weapons infrastructure to carry out the program. Not only were some key legislators unconvinced of the technical need for replacement warheads, but they questioned the administration's assumptions about the future role and size of the U.S. nuclear arsenal. The 2008 House report on the fiscal year 2008 energy and water appropriations bill requires the Energy Department to provide a "comprehensive nuclear defense and security plan," a "translation into a specific stockpile," and "a comprehensive long-term expenditure plan."

Indeed, there is great uncertainty over the future of the U.S. nuclear weapon stockpile, despite planning within the government and the Energy Department for a considerably lower number to correspond with the 2002 Strategic Offensive Reductions Treaty-perhaps 2,100 "operationally deployed" strategic nuclear weapons on December 31, 2012. This might represent a total stockpile of 4,000-6,000 bombs and warheads.

The United States should move rapidly to a stockpile of 1,000 weapons of the current type. Vigorous and challenging work in the weapons labs and a smaller and more efficient support complex can maintain the safety and reliability of these weapons.


The RRW program emerged in response to the failed attempt by the Energy Department's National Nuclear Security Administration (NNSA) to pursue another nuclear warhead, the Robust Nuclear Energy Penetrator (RNEP). That effort fell short on Capitol Hill amid first confusion and then later concern about RNEP's capabilities and effects.[3] The RNEP fiasco did little to maintain the reputation of the NNSA for integrity and technical competence.

It also seemed to convince lawmakers that they needed to find another way to provide challenging nuclear weapons design and development work at the three weapons laboratories-Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Sandia Corporation.

With RNEP gone, attention moved to the RRW program, for which competitive design studies were done at Los Alamos and Livermore. Livermore was selected by the NNSA to move to the next phase of development, and its design was renamed WR1. According to Livermore currently,

The goal of the RRW approach is to replace aging warheads with ones manufactured from materials that are more readily available and more environmentally benign than those used in current designs. RRWs can include advanced safety and security technologies, and they are designed to provide large performance margins for all key potential failure modes. Large margins enhance weapons reliability and help to ensure that underground nuclear testing will not be required for design certification.

After NNSA's selection of the Livermore/Sandia-California design, NNSA and the U.S. Navy began to develop a detailed WR1 project plan and cost estimate. The effort has since been halted. While seeking clarification on a number of related policy and technical issues, Congress stopped funding for RRW work in [fiscal year] 2008.[4]

These are very modest goals in contrast to the frequently heard need to replace warheads about whose reliability and safety there is "increasing concern." This concern is usually expanded to argue that, with the accumulation of small modifications to existing warheads in the Life Extension Programs (LEPs), we move farther from the nuclear explosion test base, and at some point, the warheads will no longer be certifiable, as asserted by Gates:

Our nuclear weapons were designed on the assumption of a limited shelf life and that the weapons themselves would eventually be replaced. Sensitive parts do not last forever. We can and do reengineer our current stockpile to extend its life span. However, the weapons were developed with narrow technical margins. With every adjustment, we move farther away from the original design that was successfully tested when the weapon was first fielded. Add to this that no weapons in our arsenal have been tested since 1992. So the information on which we base our annual certification of stockpile grows increasingly dated and incomplete. At a certain point, it will become impossible to keep extending the life of our arsenal, especially in light of our testing moratorium.[5]

I disagree. The NNSA's $5-billion-per-year science-based Stockpile Stewardship Program (SSP) may be essential in providing the foundation for the labs to design an RRW that might indeed be certifiable without nuclear testing, but that same program has provided the basis over time for increasing, not decreasing, confidence in the performance of these legacy weapons.

A key milestone in this regard occurred in late 2006. Until then, the Bush administration had based its case for the RRW program in large measure on the argument that the United States was incapable of remanufacturing plutonium pits, the core of the primary nuclear explosive in U.S. thermonuclear weapons. The NNSA argued that it would be better to start anew with something that could reasonably be traced to a nuclear test explosion but that would give expanded freedom of design in view of a post-Cold War assumption of relaxed requirements on warhead weight and yield.

Yet, in late 2006, the SSP led to the judgment by Livermore and Los Alamos that the plutonium pit in each of our stockpile nuclear weapons has a life exceeding 85 years, perhaps 100 years. This conclusion was endorsed by a technical study by JASON and was published by the NNSA.[6]

Moreover, any modifications to legacy weapons are not added willy-nilly. They can be simulated and evaluated more confidently than can the total redesign that is an RRW. Gates adds, "As I say, we've been re-engineering our stockpile now for essentially 16 years, and we are okay today. It is the longer-term prospect that concerns me." The secretary should consider the proposition that our confidence in legacy weapons can and should grow rather than diminish. What is more, his advisers should open their eyes to progress over the past 14 years.

The fact that the NNSA can now certify that pits have a lifetime of more than 85 years has removed any urgency to engineer and manufacture the RRW. Proper assessment of the accumulation of small modifications in the LEPs can be done with more certainty on the basis of the SSP than can the certification of a new, untested RRW. It remains to be determined whether an RRW can be certified, but the continued performance of legacy weapons can be more reliably certified than an RRW.

Furthermore, no analysis has been offered to show the security or cost benefits over time that would allow a reasoned decision on the RRW program versus other approaches to further reduce the possibility of theft or misuse of existing warheads, such as enhanced security features in the shipping containers for existing warheads.

It cannot be disputed that an RRW could include additional surety measures not present in the legacy weapons, but no analysis has been provided of the benefits of such measures over the many years before the RRW-1, RRW-2, and perhaps more, have fully replaced legacy weapons in the U.S. nuclear forces. Even if the RRW were perfectly secure against misuse, terrorists could concentrate on the non-RRW weapons so that surety of the entire system would not increase much until the RRW took over entirely. Of course, a U.S. RRW does nothing to increase the surety of Russian or Pakistani weapons. Encouraging other nations to develop RRWs or their equivalent is not something that should be advocated, although they should take steps to increase the surety of existing weapons.

Yet, the work done so far on the RRW program has re-energized the nuclear laboratories and their involvement in the nuclear weapons complex. Such a major effort should be undertaken every five years or so. I know firsthand from my involvement with this program that new insights have arisen from the new focus on simulation and computation. According to the Livermore annual report, one portion of the work on tantalum at high pressures "would have taken more than 20,000 years to run using the largest computer that was available 20 years ago."[7]

Quantification of Margins and Uncertainties (QMU)

The National Academy of Sciences (NAS) was asked by the NNSA, as directed by Congress, to study the application of quantification of margins and uncertainties (QMU) in the national labs.[8] I was a member of the authoring committee. The QMU was introduced by the labs themselves around 1995 in order to objectify the process of analysis and decision by which nuclear weapons are designed and certified, either initially or in the ongoing annual certification process. The QMU has been implemented rather differently at Los Alamos and Livermore and is less formally used at Sandia. It attempts to integrate the underground nuclear testing experience together with simulation and designer judgment.

In general, although the QMU has not been formally defined, it has played a constructive role. One important criterion for which there is margin and uncertainty is whether the explosive yield of the primary nuclear component exceeds that required to drive the secondary explosive to full yield. Using the best estimates of the explosive output of the primary and the required drive for the secondary, one defines in this way the margin between the two by which the primary yield exceeds the requirement. There are uncertainties in the yield of the primary and the need of the secondary, and differences arise as to how to combine these uncertainties. Clearly, even with less margin than desired, in only one-quarter of the cases (by probability) is there a significant compromise in the performance of the weapon itself. This occurs when the uncertainty in primary performance leads to a smaller yield and uncertainty in the secondary requirement leads to the need for a larger primary yield to drive the secondary explosive. This additional factor four reduction in probability would mitigate the impact of an apparently less-than-robust margin.

The QMU is clearly a stand-in for an enormous number of "button-to-boom" detailed simulations, with the accumulation of statistics. If the performance gates for which M and U are estimated are appropriately chosen, the QMU approach is apt to be conservative in estimation of weapon reliability. The QMU provides a language for communication among the weapons laboratories and the NNSA that can estimate the benefit of improved boost-gas supply [9] procedures to meet concerns about weapons yield in adverse conditions.

Nuclear Weapons Infrastructure

For many years, the NNSA has been putting forth proposals for modernizing the nuclear weapons infrastructure. In October 2008, the NNSA published its analysis of options to "transform the nation's Nuclear Weapons Complex to make it smaller, safer, more secure, and more cost-effective." This Complex-Transformation Supplementary Programmatic Environmental Impact Statement (SPEIS) puts forward a preferred option for realigning the complex, including a capability to produce 125 plutonium pits per year in Los Alamos on a single-shift, five-day-per-week basis. With even the highly conservative assumption of an 85-year pit lifetime, that target (without an additional expected surge capability to 200 pits per year) could support a stockpile of almost 11,000 nuclear weapons.

If one assumes a target stockpile of 4,000 nuclear weapons from which to field about 2,000 operationally deployed strategic nuclear weapons, the replacement of even one-half the number of current ("legacy") weapons with RRWs would require about 16 years (2,000 warheads divided by 125 warheads per year) after the transformed complex is fully operational in the year 2018 or thereabouts. That is part of the rub with the RRW program. Although the RRW program was supposed to be the basis for complex simplification and downsizing, infrastructure to support the legacy weapons would obviously be required until there were sufficient RRWs in stockpile that all legacy weapons could be dismantled.

It is also clear that the complex cannot be defined or optimized unless a decision is made as to whether 8,000, 4,000, or 999, or 300 nuclear weapons are to constitute the future total stockpile. A commitment to an RRW does not in any way promise to ease the problem of definition and operation of the complex until a quantitative plan is provided and evaluated for building RRWs and replacing legacy weapons.

Improving security of stocks of highly enriched uranium and plutonium against theft and detonation by terrorists should play a far greater role in the complex modification than it has so far, although it is one of the drivers toward consolidation of the complex. If the United States takes so long to reduce the hazard of diversion of its weapons-usable materials, how can it expect an expanded Nunn-Lugar program [10] to significantly reduce the hazard from the stocks of other countries that may be less well protected? Improved surety features in an RRW are far less effective in reducing the overall hazard of terrorist use of nuclear explosives than would be an enhanced program in security of nuclear weapons and materials worldwide, together with massive reductions in nuclear weaponry.

Figure 1 (see print edition) is a recent estimate by the National Resources Defense Council of the U.S. stockpile of nuclear weapons from 1945 to 2008.

The nuclear weapons stockpiles of China, France, and the United Kingdom are estimated to be in the few hundreds and would make up an almost invisible portion of the graph compared to U.S. or Russian holdings. Yet, U.S. national security is imperiled by states with only a few weapons and by the prospect of terrorists acquiring even a single one. Hence the importance of evaluating potential U.S. nuclear weapons activities in terms of their influence on proliferation, access of terrorists to nuclear weapons, and the reduction in the potential nuclear threat to the United States.

Implications for the U.S. Test Moratorium and CTBT

Replying to a question following his speech on October 28, 2008, Gates said, "I think that if there are adequate verification measures, [the United States] probably should" ratify the Comprehensive Test Ban Treaty (CTBT). Although the CTBT is a larger topic than can be fully addressed here, a 2002 NAS study on this topic, [11] of which I was an author, provided satisfactory answers to the question of detection of militarily significant explosive tests in violation of the CTBT as well as maintaining the safety and reliability of the U.S. nuclear stockpile under the CTBT.
The International Monitoring System (IMS), on-site inspections, and transparency measures provided for under the CTBT, combined with U.S. intelligence capabilities, are adequate to detect and deter militarily significant cheating. As the NAS report concluded,

The capabilities to detect and identify nuclear explosions without special efforts at evasion are considerably better than the "one kiloton worldwide" characterization that has often been stated for the IMS. If deemed necessary, these capabilities could be further improved by increasing the number of stations in networks whose data streams are continuously searched for signals.

Underground explosions can be reliably detected and can be identified as explosions, using IMS data, down to a yield of 0.1 [kiloton] (100 tons) in hard rock if conducted anywhere in Europe, Asia, North Africa, and North America. In some locations of interest such as Novaya Zemlya, this capability extends down to 0.01 [kiloton] (10 tons) or less.

In addition, the United States benefits from monitoring capabilities that are currently only available through the CTBT's IMS, including monitoring stations in China, Russia, and other sensitive locations that the United States would otherwise not be able to access. [12]

The NAS panel concluded that the United States "has the technical capabilities to maintain confidence in the safety and reliability of its existing nuclear-weapon stockpile under [a test ban], provided that adequate resources are made available to the Department of Energy's nuclear-weapons complex and are properly focused on this task."

According to the NAS panel, which included three former lab directors, age-related defects mainly related to non-nuclear components can be expected, but nuclear test explosions "are not needed to discover these problems and...not likely to be needed to address them."
Rather, the panel said the key to the stewardship of the arsenal is a rigorous stockpile surveillance program, the ability to remanufacture nuclear components to original specifications, the minimization of changes to existing warheads, and non-explosive testing and repair of non-nuclear components.

Since the publication of the NAS panel's report, confidence in existing warheads has increased over time. In March 2007, Thomas D'Agostino, then acting NNSA administrator, said that the SSP is "working. This program has proven its ability to successfully sustain the safety, security and reliability of the stockpile without the need to conduct an underground test for well over a decade."[13]

Given that it is well-established U.S. policy to maintain our current nuclear test moratorium, it is also clearly in the U.S. interest to solidify the global norm against testing and enhance our capabilities to detect and deter surreptitious testing that could improve the nuclear weapons capabilities of other states.


Substantial nuclear design and capability should be maintained at the national labs: The SSP should focus on the existing advanced computing capability and the modernization and expansion of the computer codes and simulations. In addition, the system ought to be challenged every five years with a competition for the design of simplified nuclear warheads, including a much broader range of options, such as the total elimination of plutonium from U.S. nuclear weapons.

The nuclear weapons infrastructure can be defined only after the target number of nuclear weapons in a particular year is selected. Since 1988, I have argued for an essentially immediate reduction to 1,000 nuclear warheads for the United States and the Soviet Union (now Russia) followed by urgent efforts to negotiate lower caps on the inventories of China, France, and the United Kingdom. The 1,000-nuclear-warhead figure would ultimately include not only deployed warheads but also those in transit, refurbishment, and reserve. Indeed, France and the United Kingdom have limited their deployed warheads, although China has made no quantitative statement about its limits. The Reykjavik-2 initiative, with a long-term goal of an appropriate security structure for eliminating nuclear weapons, argues for massive reductions on this scale as well. Henry Kissinger, Sam Nunn, Bill Perry, and George Shultz are among the leaders of this initiative.[14]

Only by a serious program to lead the way in the massive reduction of stocks of nuclear weapons and of weapon-usable materials, and by an absolute commitment not to have nuclear explosive tests can the United States play a leadership role in eliminating proliferation of nuclear weapons other states, such as Iran and North Korea.


Richard L. Garwin is an IBM fellow emeritus at the IBM Research Center, Yorktown Heights, New York; adjunct professor of physics at Columbia University; and a longtime consultant to the U.S. government on nuclear weapons and military technology.


1. U.S. Secretary of Energy, Secretary of Defense, and Secretary of State, “National Security and Nuclear Weapons: Maintaining Deterrence in the 21st Century,” July 2007, http://nnsa.energy.gov/news/1238.htm.
2. Representatives Peter Visclosky (D-Ind.) and David Hobson (R-Ohio), letter to the Bush administration on the Reliable Replacement Warhead, August 1, 2007.
3. Then-NNSA administrator Ambassador Linton Brooks later apologized for not being clearer that RNEP was neither required nor expected to penetrate many tens of meters into rock, agreeing with outside analysts such as Jonathan Medalia of the Congressional Research Service, Rob Nelson of the Union of Concerned Scientists, and an NNSA-sponsored National Academy of Sciences (NAS) study. They found that it was impossible for a RNEP to penetrate more than a few times its length and that all of the benefit from penetration would come from having the nuclear explosion one or two meters below ground level. This would provide a ground shock equivalent to a nuclear yield 20 times as large as one exploded on the surface of the ground.


There was also no pushback against the NAS conclusion that the radioactive fallout from such an underground explosion would not be contained and could kill between a few people and many hundreds of thousands, depending on the winds and the location of the explosion with respect to population centers. I was a member of the NAS committee and had also analyzed RNEP independently. Although it was outside the scope of the committee’s charge of assessment, I presented arguments why if one really wanted an RNEP, one should not take the approach of extreme “hardening” of the B61-Mod 11 so that it would penetrate into rock or concrete as well as into the earth for which B61-Mod 11 was designed. Rather, one should fit the B61-Mod 11 with a large conventional explosive “shaped charge” adjunct, so that the B61 would not have to penetrate earth at all but could travel in the cylindrical cavity excavated a few milliseconds before by the shaped charge. A trivial modification would need to be made for the weapon to detonate in flight rather than having come to rest.

No interest has been shown in acquisition of this capability, probably because RNEP was intended to provide challenging weapons design and development work rather than fulfill compelling military needs.
4. Lawrence Livermore National Laboratory, “Annual Report 2007,” June 9, 2008, www.llnl.gov/annual07/pdfs/wci.pdf . For example, the excess of predicted yield of the primary explosive of a two-stage weapon over the yield demanded for proper performance of the thermonuclear secondary. Ibid., pp. 7-8.

The report notes that Congressional funding of the RRW program is in abeyance, “while seeking clarification on a number of related policy and technical issues.” Related information from the fiscal year 2008 Omnibus Appropriations Legislation and fiscal year 2009 House Appropriations Committee report is available online here.
5. Robert Gates, speech to the Carnegie Endowment for International Peace, October 28, 2008.
6. “The classified studies looked at pits in each nuclear weapon type and gave specific information on plutonium properties, aging and other information. Overall, the weapons laboratories studies assessed that the majority of plutonium pits for most nuclear weapons have minimum lifetimes of at least 85 years.” NNSA Public Affairs, “Studies Show Plutonium Degradation in U.S. Nuclear Weapons Will Not Affect Reliability Soon,” November 29, 2006, http://nnsa.energy.gov/news/999.htm.
7. Lawrence Livermore National Laboratory, “Annual Report 2007,” p.9.
8. National Research Council of the National Academies, “Evaluation of Quantification of Margins and Uncertainties Methodology for Assessing and Certifying the Reliability of the Nuclear Stockpile,” November 2008.
9. The mixture of deuterium and tritium gases that are supplied to the hollow pit shortly before the high-explosive implosion.
10. The Cooperative Threat Reduction Program initiated in 1992 by Sens. Sam Nunn (D-Ga.) and Richard Lugar (R-Ind.) and implemented in the Defense Threat Reduction Agency.
11. National Academy of Sciences, “Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty,” 2002.
12. David Hafemeister’s recent article brings the CTBT verification debate up to date. See David Hafemeister, “The Comprehensive Test Ban Treaty: Effectively Verifiable,” Arms Control Today, October 2008, p. 12.
13. Thomas D’Agostino, Testimony Before the House Appropriations Subcommittee on Energy and Water Development, March 29, 2007 (hearing on Energy Department’s fiscal year 2008 budget).
14. George P. Shultz, William J. Perry, Henry A. Kissinger, and Sam Nunn, “A World Free of Nuclear Weapons,” The Wall Street Journal, January 4, 2007, p. A15; George P. Shultz, William J. Perry, Henry A. Kissinger, and Sam Nunn, “Toward a Nuclear-Free World,” The Wall Street Journal, January 15, 2008, p. A13.

Air Force Leaders Fired Over Nuke Handling

Secretary of Defense Robert Gates fired Air Force Chief of Staff Gen. T. Michael Moseley and Secretary of the Air Force Michael Wynne on June 5 after a report by Navy Adm. Kirkland Donald highlighted significant oversights in the Air Force’s nuclear security practices. (Continue)

Stephen Bunnell

Secretary of Defense Robert Gates fired Air Force Chief of Staff Gen. T. Michael Moseley and Secretary of the Air Force Michael Wynne on June 5 after a report by Navy Adm. Kirkland Donald highlighted significant oversights in the Air Force’s nuclear security practices.

The ousting of Moseley and Wynne followed several incidents in the past year that have heightened concerns over the Air Force’s ability to properly maintain and secure its arsenal of land-based ICBMs and nuclear-armed bombers.

Last August, a B-52 bomber flew from Minot Air Force Base in North Dakota to Barskdale Air Force Base in Louisiana wrongly and unknowingly armed with nuclear cruise missiles. (See ACT, October 2007.) In March of this year, it was reported that the Air Force had accidentally shipped four nosecone fuses for nuclear missiles to Taiwan in 2006, drawing complaints from China. (See ACT, May 2008.)

Gates’ action came after another such incident in late May when the 5th Bomb Wing, which is stationed at Minot, received a grade of “unsatisfactory” in nuclear security during a weeklong, highly anticipated inspection by the Defense Threat Reduction Agency (DTRA).

According to Air Force Times, the DTRA report, which is not publicly available, catalogs a number of startling failures in the security process. In one case, an airman was caught on tape playing video games on a cell phone. In another incident, inspectors managed to “kill” three security forces members who had failed to clear a building upon entering it. “Security forces’ level of knowledge, understanding of assigned duties, and response to unusual situations reflected a lack of adequate supervision,” said the DTRA team chief.

Gates acknowledged that this chain of events may represent a deeper problem within the Air Force in general and the nuclear forces for which it is responsible in particular. In a June 5 press conference, he characterized the Minot cruise missile incident and the Taiwan nosecone fuses incident as sharing a “common origin” and said both are symptomatic of “a degradation of the authority, standards of excellence, and technical competence within the nation’s ICBM force.” Citing a “lack of a critical self-assessment culture in the Air Force nuclear program,” Gates appointed a task force headed by former Secretary of Defense James Schlesinger to review nuclear security and stewardship. The task force will offer two rounds of recommendations, one in 60 days, the other in 90 days.

Similarly, a February 2008 Defense Science Board task force reported a widespread perception throughout the Air Force that “the nuclear forces and the nuclear deterrent mission are increasingly devalued.” The task force report catalogs a noticeable decline in attention paid to the nuclear mission by senior-level commanders by citing older Department of Defense reports. For example, a Joint Advisory Committee report from 1995 warns, “There is reason for concern about the long-term quality and quantity of nuclear weapons expertise within the [Defense Department] as the size of the [Defense Department] nuclear community shrinks and the interest level declines.”

Despite Gates’ actions, other reports pointed to ongoing problems. On June 19, a partially declassified internal “blue ribbon” investigation, triggered by the earlier Minot incident, revealed that “most sites” for the deployment of nuclear weapons in Europe have failed to meet U.S. security requirements.

In addition to the erroneous shipment of fuses to Taiwan, a June 19 article in the Financial Times reports that hundreds of missile components have apparently gone missing from U.S. stockpiles. According to the article, anonymous government officials have claimed that the number of components unaccounted for is “more than 1,000.”

This has prompted renewed criticism of the Bush administration from lawmakers who had supported Gates’ firings of Moseley and Wynne. In a June 20 letter to Gates, Sens. Bob Casey (D-Pa.) and John Kerry (D-Mass.), both members of the Senate Foreign Relations Committee, demanded an explanation for how 1,000 sensitive nuclear missile components could have simply vanished from U.S. stockpiles. “While George Bush and John McCain were preoccupied with the misguided war in Iraq, they lost sight of the real danger—terrorists getting their hands on the world’s most dangerous weapons,” said Kerry in a press release.



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