Finding 1-1: The technical capabilities for maintaining the U.S. stockpile absent nuclear-explosion testing are better now than anticipated by the 2002 Report.
Finding 1-2: Future assessments of aging effects and other issues will require quantities and types of data that have not been provided by the surveillance program in recent years.
Finding 1-3: The committee judges that Life-Extension Programs (LEPs) have been, and continue to be, satisfactorily carried out to extend the lifetime of existing warheads without the need for nuclear-explosion tests. In addition to the original LEP approach of refurbishment, sufficient technical progress has been made since the 2002 Report that re-use or replacement of nuclear components can be considered as options for improving safety and security of the warheads.
Finding 1-4: Provided that sufficient resources and a national commitment to stockpile stewardship are in place, the committee judges that the United States has the technical capabilities to maintain a safe, secure, and reliable stockpile of nuclear weapons into the foreseeable future without nuclear-explosion testing. Sustaining these technical capabilities will require at least the following:
• A Strong Scientific and Engineering Base. There must be continued adherence to the principle that the ability to assess and certify weapons rests on technical understanding of weapons phenomena, data from past nuclear-explosion tests, computations, and data from past and ongoing experiments. Maintaining both a strategic computing capability and modern non-nuclear-explosion testing facilities (for hydrodynamic testing, radiography, material equation-of-state measurements, high explosives testing, and fusion testing) is essential for this purpose.
• A Vigorous Surveillance Program. An intensive surveillance program aimed at discovering warhead problems is crucial to the health of the stockpile.
• Adequate Ratio of Margin to Uncertainty. Performance margins that are sufficiently high, relative to uncertainties, are key ingredients of confidence in weapons performance.1
• Modernized Production Facilities. Most of the nuclear weapons production facilities are old (50 years in some cases) and are both difficult and costly to operate in accordance with modern standards of safety and security.
• A Competent and Capable Workforce. Nuclear weapons work (e.g., the SSP) is key to meeting a range of challenges in the broader national security landscape. Exploration of these broader areas (e.g., nonproliferation programs, render safe,
1 Some of today’s systems already have relatively high margin-to-uncertainty ratios; others are relatively low.
etc.) can provide opportunities for intellectual stimulation and professional development that will attract a diverse, capable workforce. It is equally important to ensure that the Department of Defense, particularly the Defense Threat Reduction Agency, the Navy’s Strategic Systems Project Office, and the Air Force’s Ballistic Missile Organization maintains a technically competent workforce (Congressional Commission, 2009; U.S. Secretary of Defense Task Force on DOD Nuclear Weapons Management, 2008; Defense Science Board, 2008).
Recommendation 1-1: To address each of the essential elements of stockpile stewardship listed in Finding 1-4, NNSA, working with the Administration and Congress as appropriate, should:
• Maintain a continuing dynamic of experiments linked with analysis. Both are essential to maintaining the capability to render judgments about stockpile issues.
• Maintain a vigorous surveillance program that is systematic; is statistically based where possible; and continuously reflects lessons learned from annual surveillance, LEPs, fixing problems, and science-based analysis. Nondestructive tools and experimentally validated computational analysis should be developed and applied to introduce more predictive capability into the surveillance system.
• As part of each LEP, explore options for achieving adequate margins through reuse or replacement scenarios in addition to refurbishment, to determine how best to meet military, technical, and policy objectives. Assess uncertainties associated with each scenario.
• Develop and implement a long-term production facility modernization plan. This should include maintaining a plutonium science and production capability, including the ability to produce various types of pits for weapons in the stockpile.
• Broaden the base of its nuclear expertise by involving nuclear-capable personnel in related national security projects (nuclear forensics, intelligence, threat reduction programs, basic science applications of stewardship activities, etc.).
Finding 1-5: To maintain a test readiness capability of 24-36 months as required by PDD-15, some test readiness capabilities must be explicitly maintained in addition to the Stockpile Stewardship Program. Test Readiness draws on SSP capabilities but requires a suitable test site, a set of specialized equipment and infrastructure, and a body of specialized knowledge. The pacing item in resuming nuclear explosive testing may be regulatory rather than technical.
Recommendation 1-2: To maintain a test readiness posture of 24-36 months, NNSA should:
• Preserve the Nevada Test Site’s ability to host a nuclear-explosion test;
• Support the containment capability unique to underground nuclear-explosion testing;
• Maintain seismic data necessary to meet U.S. obligations under the Threshold Test Ban Treaty should testing resume;
• Maintain the radiochemistry laboratory infrastructure and drill-back capability;
• Support fast readout requirements and prompt diagnostic equipment;
• Maintain a library that includes testing methods, containment rack designs, procedures, processes; and other relevant information;
• Maintain nuclear-certifiable emplacement cranes;
• Maintain field-test neutron generators;
• Establish a process for obtaining waivers from health and environmental regulations if required, but, given the frequency with which laws change, do not seek such waivers in advance.
NNSA should include all of these elements within the SSP and evaluate their status as part of the annual assessment of the fulfillment of safeguards recommended in Chapter 3 of this report.
Finding 2-1: U.S. National Technical Means provide monitoring capability that is superior to that of the CTBTO, but the use of U.S. NTM for diplomatic purposes may be constrained due to its largely classified nature.
Finding 2-2: The International Monitoring System provides valuable data to the United States, both as an augmentation to the U.S. NTM and as a common baseline for international assessment and discussion of potential violations when the United States does not wish to share NTM data.
Recommendation 2-1: The United States should support both the completion of the IMS and its operations, training, and maintenance, whether or not the CTBT enters into force.
Finding 2-3: Independent of the CTBT, the national security interests of the United States and its allies require the seismic monitoring of foreign nuclear-explosion tests.
Finding 2-4: Technical capabilities for seismic monitoring have improved substantially in the past decade, allowing much more sensitive detection, identification, and location of nuclear events. More work is needed to better quantify regional monitoring identification thresholds, particularly in regions where seismic waves are strongly attenuated.
Recommendation 2-2: AFTAC should study the extent to which detection thresholds could be improved by making fuller use of the authenticated data from the IMS as well as targeted use of calibrated non-IMS seismic stations to help characterize special events of high concern.
Recommendation 2-3: To meet its national security needs, the United States should continue to enhance and sustain its NTM seismic monitoring capabilities.
Finding 2-5: One of the major advances in monitoring in the last 10 years is that most of the IMS seismic stations are operating now, and most of those have been certified for data quality (including calibration) and integrity (with respect to tampering and data authenticity). The threshold levels for IMS seismic detection are now well below 1 kt worldwide for fully coupled explosions.
Finding 2-6: Seismic technologies for nuclear monitoring have the potential to improve event detection, location, and identification substantially over the next years to decades.
Recommendation 2-4: The United States should renew and sustain investment in seismic R&D efforts to reap the rewards of new methodologies, source models, Earth models,
and data streams to enhance underground nuclear explosion monitoring, regardless of the status of CTBT ratification.
Finding 2-7: Closer collaboration among the U.S. monitoring, NTM, national laboratory, and academic communities would help the United States keep up with new developments and technologies for seismic nuclear-explosion test monitoring.
Finding 2-8: AFTAC has demonstrated notable achievements over the past decade, including major enhancements in all aspects of radionuclide monitoring.
Recommendation 2-5: The United States should continue to actively support radionuclide collection, including R&D activities to better discriminate nuclear-test signature radionuclides from background, thus improving the ability to detect well-contained and lower-yield nuclear-explosion tests.
Finding 2-9: In the past 10 years, the IMS radionuclide network has gone from being essentially non-existent to a nearly fully functional and robust network with new technology that has surpassed most expectations.
Finding 2-10: The IMS has made significant improvements in data processing.
Finding 2-11: Ongoing measurement and understanding of global backgrounds of radionuclides relevant to nuclear-explosion monitoring are critical for improving radionuclide detection.
Recommendation 2-6: The United States should support research needed to understand the global background of radionuclides.
Finding 2-12: In at least 50 percent of nuclear-explosion tests near 1 kt or larger, even those carried out by experienced testers, xenon noble gases may be detectable offsite above the detection limits of the IMS (0.1 to 0.2 mBq/m3) from prompt venting of nuclear-explosion tests; also, long-term seepage of appreciable noble gases would be expected that could be detectable, both offsite and onsite.
Finding 2-13: The IMS detection threshold for in-water explosions is 10 tons (0.01 kt) or below worldwide and below 1 ton (<0.001 kt) throughout the majority of the world’s oceans.
Finding 2-14: As of 2010, two of the six hydroacoustic stations of the IMS were damaged and became non-operational after installation and certification; one will be restored.
Recommendation 2-7: The U.S. should assess the need for data from the damaged hydroacoustic stations and, if appropriate, work with the CTBTO to restore these stations to operational capability.
Finding 2-15: Infrasound detection is a valuable approach for monitoring atmospheric nuclear explosions.
Finding 2-16: Integration of infrasound with seismic data and analysis will provide better detection, location, and identification of explosions.
Finding 2-17: Sustainment of the U.S. satellite monitoring capability to detect any nuclear explosion in the atmosphere or space, whatever its origin, will continue to be in the interest of the United States and its allies, regardless of whether the CTBT enters into force.
Recommendation 2-8: Enhanced satellite nuclear detonation detection systems should be deployed in upgrades to GPS (GPS Block IIF and Block III) and the follow-on to DSP, the Space-Based Infrared System (SBIRS). Provision for adequate ground-based data processing is also essential. Decisions regarding whether and at what level to maintain the satellite nuclear detonation detection capability should be made as part of high-level national security policy and acquisition assessments.
Finding 2-18: Although the IMS is operating effectively, meeting the needs of CTBT entry into force will require more staff and easing of budgetary constraints.
Recommendation 2-9: The United States and others should ensure that priorities and funds are sufficient for IMS to meet ongoing needs, including after entry into force.
Finding 2-19: A technical exercise that tests the advantages of incorporating auxiliary seismic station data into the CTBTO’s automated system would be useful to demonstrate the feasibility of this proposed improvement.
Finding 2-20: Location accuracy of events identified with waveform signals (seismic, hydroacoustic or infrasound) can be improved technically by better calibration to reduce the size of error ellipses and to improve detection and location accuracy. A technical review that evaluates calibration efforts, such as station tuning, phase labeling, and location accuracy, could identify ways to improve absolute location accuracy.
Finding 2-21: The CTBTO benefits from systematic, sustained interaction with the broader scientific communities involved in areas relevant to its mission.
Finding 2-22: A CTBTO on-site inspection (OSI) would have a high likelihood of detecting evidence of a nuclear explosion with yield greater than about 0.1 kilotons, provided that the event could be located with sufficient precision in advance and that the OSI was conducted without hindrance.
Finding 2-23: There are many opportunities for confidence-building measures to support nuclear explosion monitoring, particularly through engaging scientists and engineers in cooperative efforts.
Recommendation 2-10: The United States should pursue bilateral (and, to the extent justified and politically feasible, limited multilateral) programs of scientific cooperation for purposes of confidence building in support of monitoring nuclear explosions. These programs should be periodically reviewed for effectiveness and for appropriate controls on information.
Finding 2-24: Test-site transparency agreements can provide a mechanism for mitigating concerns about very-low-yield testing (yields up to about 1 ton).
Finding 3-1: A decreasing fraction of the budget for the nuclear weapons program is available for the actual technical work that must be accomplished to sustain the U.S. deterrent.
Finding 3-2: A strong national commitment to recruiting and sustaining a high-quality workforce; recapitalizing aging infrastructure and force structure; and strengthening the science, engineering, and technology base is essential to sustaining a safe, secure, and reliable stockpile, as well as necessary explosion-monitoring capability for the United States.
Recommendation 3-1: The Administration, in concert with Congress, should formulate and implement a comprehensive plan that provides a clear vision and strategy for maintaining the nation’s nuclear deterrence capabilities and competencies, as recommended in the 2010 Nuclear Posture Review and related studies.
Finding 3-3: The current contract system for the nuclear weapons laboratories has not produced a more innovative, efficient, and cost-effective approach to carrying out the tasks of the nuclear weapons program. Rather, there is evidence that the present system acts as a significant barrier to many of the objectives delineated in this report.
Recommendation 3-2: The DOE/NNSA should re-evaluate the current contract system for carrying out the tasks of the nuclear weapons program. At a minimum, any new approach should:
• Reduce the number of requirements in directives and simultaneously transform those requirements to performance goals (prescribing what must be done, not how to do it).
• Shift the balance of incentives in contracts for the weapons laboratories to emphasize successful implementation of the technical mission.
Finding 3-4: Technical improvements needed for monitoring the CTBT (and other treaties) would benefit greatly from better access to skilled personnel and computational and experimental facilities at the national labs. This access is needed by agencies with CTBT monitoring and verification responsibilities.
Recommendation 3-3: Provisions of a recently-agreed-to governance charter should be implemented to enable better access to skilled personnel and capabilities at the national labs by agencies other than DOE/NNSA. Such access will directly benefit research and technology development aimed at improving CTBT (and other treaty) monitoring and verification.
Finding 3-5: Air Force Research Laboratory (AFRL) funding for nuclear explosion-monitoring R&D is significantly lower than in past decades, whereas the monitoring task has become far more complicated.
Recommendation 3-4: For the United States to monitor effectively for the possibility of nuclear-test explosions, the U.S. Government should fund a robust R&D program to maintain ongoing operational capabilities and to support achievable improvements.
Finding 3-6: Continued enhancement of the USAEDS is necessary to monitor the CTBT. Research and development of advanced monitoring capabilities are needed, including research and training at universities of the next generation of scientists and engineers.
Recommendation 3-5: A sustained, predictable program of investment in nuclear-explosion monitoring R&D should be coordinated among the responsible U.S. agencies. This program should specifically include investments in university research and training programs focused on technical disciplines critical for treaty monitoring.
Finding 3-7: Year-to-year funding for the Ground-Based Nuclear Explosion Monitoring (GNEM) R&D program has decreased in recent years. The decline of funding for university research is jeopardizing R&D and training of the next generation of researchers.
Recommendation 3-6: The DOE/NNSA Ground-Based Nuclear Explosion Monitoring (GNEM) Program merits sustained, predictable funding, including funding for university investments through a competitive, peer-reviewed process.
Finding 3-8: Planned enhancements to the U.S. satellite nuclear detonation detection capability are necessary to adequately monitor the CTBT. Even without the CTBT, these enhancements to the USNDS capability are important to maintaining and improving the USAEDS.
Recommendation 3-7: The DOE/NNSA and the U.S. Air Force joint satellite-based monitoring program (USNDS) should continue planned enhancements needed to monitor the CTBT through 2020 and beyond. Advanced technology R&D should continue to enable future enhancements and anticipate surprise.
Finding 3-9: The current budget for the IMS allows operating its stations on a 24/7 basis; however, the stations are operating on a provisional basis, without weekend and emergency support contracts. The International Data Centre (IDC), now staffed for a limited number of hours each weekday, would have to move to 24/7 operation under CTBT entry into force.
Recommendation 3-8: The United States should support the CTBTO in its annual assessed and voluntary contributions to ensure that the IMS is fully installed and, with the IDC, is ready to meet CTBT entry-into-force obligations, including support for operating costs and long-term maintenance and repair of monitoring stations.
Finding 3-10: The OSI capability of the CTBTO lags behind the readiness of the IMS; however, steps have been taken, such as the 2008 Integrated Field Exercise, which have improved OSI capabilities significantly.
Recommendation 3-9: The United States should support the CTBTO OSI work by participating fully in all of its aspects, including training and field exercises.
Finding 3-11: Without agile production capabilities, it is not possible to promptly correct deficiencies revealed by surveillance or to remanufacture components or weapons when required.
Recommendation 3-10: The U.S. CTBT safeguards should include the maintenance of adequate production and non-nuclear-explosion testing facilities.
Finding 3-12: There is currently no mechanism that would enable Congress to assess whether the U.S. CTBT safeguards were being fulfilled after entry into force.
Recommendation 3-11: Under the CTBT, the Administration should prepare an annual evaluation of the ongoing effectiveness of safeguards and formally transmit it to Congress.
Finding 4-1: The Nuclear Weapon States have been able to maintain their nuclear weapons programs under a nuclear-explosion-test moratorium and are likely to be able to make nuclear weapons modifications that fall within the design range of their test experience without resorting to nuclear-explosion testing.
Finding 4-2: Hydronuclear tests would be of limited value in maintaining the United States nuclear weapon stockpile in comparison with the advanced tools of the Stockpile Stewardship Program.
Finding 4-3: Based on Russia’s extensive history of hydronuclear testing, such tests could be of some benefit to Russia in maintaining or modernizing its nuclear stockpile. However, it is unlikely that hydronuclear tests would enable Russia to develop new strategic capabilities outside of its nuclear-explosion test experience.
Finding 4-4: An evader determined to avoid detection would test at levels the evader believes would have a low probability of detection.
Finding 4-5: Mine masking is a less credible evasion scenario than it was at the time of the 2002 Report because of improvements in monitoring capabilities.
Finding 4-6: With the inclusion of regional monitoring, improved understanding of backgrounds, and proper calibration of stations, an evasive tester in Asia, Europe, North Africa, or North America would need to restrict device yield to levels below 1 kiloton (even if the explosion were fully decoupled) to ensure no more than a 10 percent probability of detection for IMS and open monitoring networks.
Finding 4-7: For IMS and open monitoring networks, methods of evasion based on decoupling and mine masking are credible only for device yields below a few kilotons worldwide and at most a few hundred tons at well-monitored locations.
Finding 4-8: The States most capable of carrying out evasive nuclear-explosion testing successfully are Russia and China. Countries with less nuclear-explosion testing experience would face serious costs, practical difficulties in implementation, and uncertainties in how effectively a test could be concealed. In any case, such testing is unlikely to require the United States to return to nuclear-explosion testing.
Finding 4-9: Better technical understanding of the decoupling process in various types of geologies would likely improve the capability to detect evasive nuclear-explosion testing.
Recommendation 4-1: If the possibility of evasive nuclear-explosion testing through cavity decoupling continues to be a concern, the United States should:
• Apply modern computational and experimental methods to understand the decoupling process in various geologies;
• Identify areas such as geologic salt domes advantageous for decoupling and consider the need for additional monitoring; and
• Identify indicators that a country is using—or may be planning to use—decoupling as an evasion strategy.
Finding 4-10: Threats could arise from clandestine nuclear weapons activity. For instance, a country with no testing experience and a modest industrial base could confidently build and deploy a single-stage, unboosted nuclear weapon without any testing, if it had access to sufficient quantities of fissile material. These advances could be made whether or not the CTBT were in force. However, it is highly likely that the United States could counter these threats without returning to nuclear-explosion testing and thus could respond equally well whether or not the CTBT were in force.
Finding 4-11: The value of low-yield evasive underground testing to a particular country depends on that country’s nuclear-explosion test experience and/or design sophistication.
• Nuclear Weapon States could use low-yield evasive testing to partially validate design codes and modernize their arsenals.
• Countries with lesser test experience could build confidence with weapons physics experiments or develop and certify inefficient, unboosted fission weapons that might pose a regional threat.
Because such tests may be undetectable, these advances could be made whether or not the CTBT were in force.
Finding 4-12: Russia and China are unlikely to be able to deploy new types of strategic nuclear weapons that fall outside of the design range of their nuclear-explosion test experience without several multi-kiloton tests to build confidence in their performance. Such multi-kiloton tests would likely be detectable (even with evasion measures) by appropriately resourced U.S. national technical means and a completed IMS network.
Finding 4-13: Other States intent on acquiring and deploying modern, two-stage thermonuclear weapons would not be able to have confidence in their performance without multi-kiloton testing. Such tests would likely be detectable (even with evasion measures) by appropriately resourced U.S. national technical means and a completed IMS network.
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