Department Seal The Stockpile Stewardship Program
Fact Sheet released by the Bureau of Arms Control,
U.S. Department of State, Washington, DC, October 8, 1999

Since the cessation of nuclear underground testing, the Department of Energy has developed the science-based Stockpile Stewardship Program to ensure the safety, security and reliability of the nation's stockpile.

This approach, combined with experimental validation and non-nuclear testing, differs from the design-test-certify approach used prior to 1992. It aims to achieve a comprehensive, science-based understanding of nuclear weapon systems. The U.S. relies on science-based understanding to reduce the risk that a significant fraction of the stockpile could fail.

The $4.5-billion-per-year budget for the Stockpile Stewardship is significantly less than the historical cost of nuclear weapons activities prior to 1992. And even if nuclear testing were resumed, DOE could not safely reduce planned science-based simulations and non-nuclear tests by any significant amount. The resumption of testing, therefore, would most likely require a significant increase in expenditures -- new facilities at NTS, as well as a significantly increased manufacturing complex would be required to resume testing.

No Testing Is Needed At This Time

The stockpile is well-tested, and nuclear testing was principally used in the development of new warheads and to validate solutions to known problems. Over 50 years' experience in stockpile monitoring provides a basis for addressing potential issues.

Current surveillance data provide no indication of problems that would require a nuclear test. Near and long-term problems are being addressed. Three annual certifications of stockpile safety and reliability have been completed and a fourth is almost complete. Each annual certification of the stockpile has resulted in a formal statement that the nation's nuclear stockpile is safe and reliable and no testing is needed at this time.

Experienced staff using experimental facilities, modeling complex nuclear explosive processes using the new super computers and archived nuclear test data have allowed the DOE to successfully address each stockpile issue since the cessation of nuclear testing in September 1992. Further advances in nonnuclear experimental capability and computational modeling will allow us to meet the challenge posed by the aging of the stockpile and retirement of experienced designers. Enhanced surveillance tools under development are providing improved methods to both detect and predict aging problems.

By using existing analytical and experimental tools and essential competitive peer review by the two physics design laboratories, several issues and challenges were addressed since September 1992 without nuclear testing. These include the B61-11, W87 service life extension program, and several potential warhead issues, identified through surveillance, which were determined to not impact performance.

Stockpile Stewardship in Action

The Stockpile Stewardship program has yielded concrete results in many different areas:

The Stockpile:

  • Certified the stockpile for 3 consecutive years and assessed that nuclear testing is not necessary to resolve weapons issues. The fourth annual certification process is nearly complete.

  • B61-11 Bomb Modification. Development of earth-penetrating capability incorporating modern safety features to replace outdated B53 bomb by modifying an existing weapon type. Status: Completed.

  • W87 Life Extension Program. Peacekeeper Warhead - updated and modernized using hydrodynamic tests, laser studies, innovative flight test diagnostics and laboratory peer review along with complex modeling and simulation capabilities. This provides high confidence in changes without nuclear testing. Status: In production.

  • W76 and W80 Life Extension. Weapons in stockpile beyond design life will be modernized as necessary to remain viable. Design labs are evaluating all parts of the weapon - explosives, plastics, metals, structural/dynamic capabilities, surety features, gas transfer systems, physics issues and surveillance requirements. They will obtain baseline data, use modern scientific and computational capabilities coming on line to certify weapons for use after modernization is completed. Status: In design phase.
Restoring Manufacturing Capabilities:
  • Tritium production: DOE made the decision to use TVA reactors as primary source of tritium production with accelerator option as back-up technology. Irradiation of tritium producing components begins in 2003.

  • Pit manufacturing:
    • FY 1998 -- LANL fabricated prototype development pits, the first since the closure of the Rocky Flats Plant in 1989.

    • FY 2001 -- the first pit qualified for stockpile use expected.

    • FY 2007 -- LANL preparing for limited capability to manufacture replacement pits for those destroyed during surveillance activities.
Right-sizing and Modernization of the Manufacturing Complex:

The weapons complex continues to meet the day-to-day requirements of the stockpile. Size of the manufacturing complex is being reduced -- updated capabilities are being added to meet current and projected manufacturing requirements.

  • Kansas City plant has begun qualified production of tritium reservoirs meeting new production requirements for the W76, W80 and W88 warheads.

  • Sandia is to begin production of neutron generators projected to deliver about 300 units in FY2000.

  • rY-12 Plant has resumed uranium processing in support of the W 87 Life Extension Program.


  • Enhanced Surveillance Program -- developing technologies, methods, fundamental understanding of material properties and weapons science to better detect and predict the effects of aging on reliability and safety. Studies confirm that stockpile high explosives are stable, enabling reuse of W87 high explosives.

  • Sub-critical experiments -- to understand weapons physics, properties of aging plutonium, pit production qualification and pit certification:
    • Sub-critical program supports nuclear test readiness as directed by the President as a safeguard to the CTBT;
    • FY 1999 -- three sub-critical experiments conducted, for a total of 7 since 1997;
    • FY 2000 -- two sub-critical experiments planned.

  • Weapon-component and system testing to assess all aspects of a nuclear weapon.
Advanced Capabilities to Ensure Future Assessment, Certification of Aging Stockpile:

Facilities under construction will provide advanced experimental capabilities essential for future stockpile assessments and to validate advanced computer simulation codes. Examples:

  • National Ignition Facility (NIF) will generate temperatures and pressures approaching those inside a detonating nuclear weapon, to validate computer based predictions, and demonstrate how aged or changed materials in weapons could behave under these unique conditions.

  • Dual-Axis Radiographic Hydrotest Facility (DARHT) will examine an imploding pit model from two different directions.
    • Experiments on first axis of DARHT began in FY 1999;
    • Second axis under construction to be completed in FY 2002.
Advanced Computer Modeling and Simulation (ASCI):

High performance computational modeling and numerical simulation are essential for integration of theory, data from past nuclear tests, and new experimental results. Advanced application codes, computing platforms, various tools and techniques are being developed and integrated into ongoing stockpile computational activities:

  • Blue Pacific (Lawrence Livermore National Laboratory) -- Achieved world-record 1.2-trillion floating point operations per second (teraOPS).

  • Blue Mountain (Los Alamos National Laboratory) -- Delivered 3 teraOPS machine as the most recent step on the path to our long range goal of balanced systems capable of 100 teraOPS.

Annual Certification of the Stockpile

The annual review takes a snapshot of all aspects of the Stockpile Stewardship Program. This annual process involves DoD agencies through established joint working groups, and independent, expert review chartered by the Commander, United States Strategic Command.

Based on in-depth review, the nuclear weapons laboratory Directors provide a technical assessment of the safety and reliability of each weapon type in the stockpile, and state whether nuclear testing is required.

This assessment includes analysis of nuclear weapon safety and security, and performance changes that would affect military effectiveness. The effort uses all available sources of information on each weapon type that comes from the Stewardship Program, including data from non-nuclear hydro-dynamic tests, subcritical experiments, materials evaluation, enhanced surveillance activities, supercomputer calculations, and stockpile surveillance efforts. With data generated throughout the year, the laboratories assimilate all information related to a particular weapon type and prepare an assessment of the condition of the stockpile.

Meeting Changing Requirements

The Stockpile Stewardship Program is providing valuable tools today and will continue to yield results in development and certification efforts to meet changing requirements. The following examples further illustrate initiatives in facilitating life extension and modifications to the stockpile.

B61-11 Modification

By applying high speed computers and existing experimental capabilities (lasers and pulse power), DOE successfully delivered a modified B61-11 to meet military requirements.

The B61-11 development effort demonstrated a full range of Stockpile Stewardship capabilities. The program to develop the B61-11 with earth penetrating capabilities was accomplished in a minimum amount of time to allow replacement of the aging B53 warhead with a weapon having modern safety features. The effort included the design of an external case that protects the B61-7 bomb from the severe impact associated with earth penetration and still allow the bomb to work in its intended fashion.

The certification effort took advantage of Accelerated Strategic Computing Initiative (ASCI) capabilities by running models of the B61-11 on the new massively-parallel computer. This allowed analysis of the forces and environments experienced by an earth penetrating weapon and greatly assisted in the design and certification process necessary to put this modified weapon in the active inventory.

W87 Life Extension Program (LEP)

New flight test technologies, advanced simulation techniques, and experimental capabilities provided the basis for development and certification of the W87 "MX" warhead.

Another Stockpile Stewardship success is the life-extension and modernization of the W87 warhead used on the Air Force's Peacekeeper missile, and for the potential use in a single reentry vehicle configuration on the Minuteman missile if Peacekeeper is retired.

The W87 design was updated and modernized using modeling and simulation capabilities with data from previous nuclear tests of the W87 warhead. The use of hydrodynamic tests, laser experiments, and computer simulations allowed the designers of the life-extension options for the W87 to have high confidence in the changes without conducting underground nuclear tests.

To support this modernization, the use of flight tests and miniaturized instrumentation technology allowed realistic measurement of the actual environments experienced by the W87 weapon. The added use of engineering proof-testing in thermal, shock, and vibration environments with the W87 helped validate the design.

The use of laboratory peer review throughout these activities allowed for independent review of the design and development activities using independent models and calculations to validate the work of the design labs.

This program involved the production complex including weapons disassembly and assembly at Pantex, uranium enrichment and secondary fabrication at Y-12 and nonnuclear component production and certification at Kansas City.

W76 and W80 Life Extension

Future life extension programs are relying on Stockpile Stewardship experimental and computational capabilities to obtain baseline weapon data, analyze and validate performance, and ensure conformance to military requirements. As the W76 and W80 warheads approach their anticipated design life, modifications to extend their lifetime are being studied and assessed so that these warheads continue to be viable in the nation's nuclear deterrent forces.

In late fall of 1998, DOE and DoD began to identify feasible life extension options and the costs associated with modernizing these weapons. The effort includes the analysis of all aspects of each weapon design including revalidation of the Military Characteristics and Stockpile-to-Target Sequence for these weapons to assure that all requirements and environments are still valid.

The design laboratories are evaluating all aspects of the weapon including an assessment of the explosives, plastics, metals, structural/dynamic capabilities, surety features, gas transfer systems, physics issues, and surveillance requirements.

The laboratories will rely heavily on the current tools of Stockpile Stewardship to provide analysis of the performance of changes to these stockpiled weapons. The scientific and computational capabilities in the stewardship program will be used by the design laboratories to certify that the weapons still meet the DoD military requirements even after the life-extension and modernization features are incorporated into these weapons. This effort will be accomplished without reliance on nuclear testing.

Developing Advanced Capabilities: An Example

The National Ignition Facility (NIF), under construction at the Lawrence Livermore National Laboratory, is a key element of the Stockpile Stewardship Program. When complete, NIF will be the world's most powerful laser, with 50 times more energy than any existing laser.

NIF will produce, for the first time in a laboratory setting, conditions of matter close to those that exist inside detonating nuclear weapons. This ability can be used directly for physics experiments to increase understanding of the performance of nuclear weapons and to validate and benchmark nuclear weapons simulation codes. These capabilities are needed to maintain a safe, secure, and reliable weapons stockpile.

The underlying science of the NIF remains sound. The technology of the laser has been demonstrated.

The sheer size and complexity of the laser assembly and integration in a clean-room environment has led to a decision to change from in-house assembly to contracting out to the best in industry. This change is largely responsible for the positive cost and schedule impacts.

Recent events do not change the fact that NIF will make a major contribution to our national security and has great potential for scientific discovery.

Reinvigorating the National Laboratories

The Stockpile Stewardship Program is reinvigorating the laboratories through a strategy of providing a clear focus on the stockpile, maintaining programmatic integration, achieving technical excellence, and by sustaining the Nation's nuclear weapon stockpile.

The Stockpile Stewardship Program is focused on maintaining the safety, security and reliability of the stockpile. During the coming decade, several major weapon systems are scheduled for refurbishment. This has given the laboratories and plants a sense of purpose and challenge.

Integrating the major elements of the weapons complex, the three weapons laboratories, the Nevada Test Site, and the production complex, is promoting greater collaboration and participation.

By making major investments in facilities and capabilities, DOE is developing a research and development infrastructure that remains second-to-none. Examples include National Ignition Facility, Dual-Axis Radiographic Hydro Test facility, Los Alamos Neutron Scattering Center, Atlas, and the Accelerated Strategic Computing Initiative Supercomputers. Excellence in facilities and capabilities is a cornerstone in attracting and retaining the best technical personnel.

The Stockpile Management and Restructuring Initiative is "right-sizing" and modernizing the production complex to meet forecasted requirements for the 21st century.

Funding for the SSP

Since the cessation of underground nuclear testing at the end of FY 1992, the Department of Energy has spent a total of about $28 billion through FY 1999 to maintain high confidence in the safety, security, reliability and performance of the nation's enduring nuclear weapon stockpile.

Joint DOE/DOD program planning targets a funding level of about $4.5 billion annually through the current 5 year period.

This budget level supports implementation of the Stockpile Stewardship Plan, including:

  • Stockpile work to meet maintenance, refurbishment, and surveillance requirements detailed in the Nuclear Weapons Stockpile Plan;
  • Research to develop and maintain critical capabilities needed to continue certification of the stockpile in the long term;
  • Construction of experimental, computational, and infrastructure facilities to support stockpile and research objectives; and
  • Federal oversight of the programs through the DOE.
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