The W80, designed by Los Alamos, was deployed in air-launched and sea-launched cruise issiles. Approximately 350 nuclear SLCMs were produced, and all remain in storage. NRDC also estimated that the W80-1 stockpile included a total of 1,400 warheads remain in stockpile associated with the 900 ALCMs that are in storage with their warheads removed. NRDC estimated that a total of about 400 W80s were deployed to arm ACMs.
A nuclear weapon system consists of a delivery vehicle, a nuclear warhead, and those components (facilities, support equipment, procedures, and personnel) required for its operation. The surface launched Tomahawk Land Attack Missile-Nuclear (TLAM-N) weapon system on board a ship included a BGM-109A-l cruise missile with a W80-0 nuclear warhead, deck mounted armored box launchers, a weapon control system, and a mission planning system.
High explosives comprise the major hazard associated with accidents involving nuclear weapons. The Tomahawk nuclear warhead contains a new type called "insensitive" high explosive, which is designed to resist detonation from energy sources other than the source intended to fire the weapon.
In a nuclear weapon accident involving high explosives, there is some possibility of a detonation of the explosive -- either a single explosion or several small explosions. The breakup of a nuclear weapon due to impact or a small explosion could result in the local scattering of small pieces of high explosive. In this condition, explosives are more unstable and may detonate.
If a nuclear weapon is involved in the flame of a fuel fire, the high explosive may ignite, burn, and detonate. In a fire, the high explosive may also melt, flow out of the weapon, and resolidify. In this state, the explosive may be sensitive to shock and detonate. When unconfined outside the weapon, high explosives may also burn, producing toxic gases and leaving a toxic residue.
The ignition or detonation of the high explosive in a nuclear weapon involved in a fire can be prevented if the explosive's temperature is kept below certain degrees. To protect the TLAM-N and the W80-0 nuclear warhead, the armored box launcher includes fire suppression systems that automatically activate at temperatures considerably below the high explosive ignition or detonation temperature.
To prevent a nuclear weapon in an accident from producing a nuclear yield, strong-link safety devices and weak-link components are installed to work together to achieve nuclear detonation safety. The strong-link safety devices make the warhead incapable of a nuclear explosion by maintaining their integrity in an accident environment until key weak-link components fail and provide permanent protection. To prevent unauthorized launching of a missile, a coded order conveying nuclear release authority must be received and authenticated by a two-man control team and verified by the commanding officer. To prevent an inadvertent launch of a missile, critical electrical cables from the armored box launcher are not connected to the missile until launch procedures are initiated. To help ensure adequate shipboard security, TLAM-N is protected by an intrusion detection alarm system that indicates an intrusion, both visually and audibly, at a continuously manned station capable of dispatching a security team.
The search for nuclear weapon system safety is a continuous process, beginning early in development and continuing through-out the life cycle of the system. The TLAM-N system initial safety study, completed in 1982, evaluated the proposed operational concept and design safety features. The preoperational safety study for the surface launched TLAM-N, completed by the Navy in 1984, included preparation of system safety rules and a determination that the system met the four DOD safety standards.
These safety study reports and other classified documents showed the TLAM-N W80-0 nuclear warhead to be one of the safest, most modern designs in the nuclear weapon inventory. Further, TLAM-N safety features and procedural safeguards, intended to bring the system into compliance with DOD safety standards, if implemented properly, should reduce the danger of a nuclear weapon accident to a minimum.
W80-3 Life Extension Program
Based on a decision by the DoD to reduce the number of W80 weapons [ie, inactivation of the AGM-129A Advanced Cruise Missile], the technical drivers for conducting the Life Extension Program [LEP] were relieved. The W80-3 LEP was cancelled by the Nuclear Weapons Council (NWC) on 10 May 2006. At the time of cancellation, the program had completed 33.7 percent (cumulative) of the approved activities. The W80-3 LEP program stopped LEP activity and prepared for full shutdown in FY 2007. Although the W80-3 LEP was cancelled, two weapon LEPs (B61 and W76) continued on a success-oriented refurbishment schedule to meet DoD requirements.
The W80 LEP was to extend the life of the W80 for an additional 20 years. Previous activities included qualification and certification activities to ensure refurbished warheads meet all required military characteristics; replacing the neutron generator, trajectory sensing signal generator, gas transfer system, and other associated components.
The Nuclear Weapons Council (NWC) approved the refurbishment of the W80 in the beginning of FY 2001. W80 refurbishment was scheduled to begin in FY'06. The Block 1 refurbishment of the warhead (about one third of the warheads in the stockpile) will focus on replacing the current gas transfer system with an Acorn design, new neutron generators, redesign of the warhead electrical system, addition of improved surety features and replacement of other associated components. The need to perform refurbishment work is driven by several factors including: age related effects that must be addressed to ensure the continued performance of the warhead, minimizing weapon movements between DoD and DOE, and infrastructure and capacities issues within the weapons complex. The FPU of the Block 1 design will be available in the second quarter of FY 2006, and Block 1 production is scheduled for completion in FY 2010. During the Block 1 production, a decision will be made to either continue Block 1 retrofits on the entire W80 stockpile, change to a Block 2 retrofit that could include enhanced surety options, or stop the retrofit altogether. The Block 2 effort, if approved by the NWC, would have continued from FY 2011 to FY 2017 to refurbish the remaining W80 warheads.
The W80 (ALCM) will need replacement of its neutron generators. This provided an opportunity to improve surety features and introduce a new gas transfer system.
Following a production lot failure due to an initiation problem, during 1999 Sandia rapidly redesigned and validated the MC3323A thermal battery for the W80 Joint Test Assembly. Sandia used its in-house dry room operation to build, qualify, and ship 32 of the redesigned thermal batteries. Enser Corporation staff from Tampa worked alongside Sandia personnel to build the batteries and deliver them on time.
In March 2003 the DOE IG reported [Refurbishment of the W80 -- Weapon Type (DOEJIG-0590)] that an audit disclosed that it was unlikely that NNSA's W80 refurbishment project would meet scope, schedule, and cost milestones established in the W80 NNSA Project Plan. Further, key management controls to oversee the project were not in place or operating as intended.
The W80-3 Life Extension Program team developed a model-based qualification approach to qualify the W80 refurbished warhead. The W80 and the Accelerated Strategic Computing Initiative (ASCI) teams collaborated to evaluate the W80 warhead in abnormal environments. The analysts used Sierra-based ASCI codes to simulate the mechanical damage due to a dropped W80-1 warhead and the thermal response of the W80-1 warhead in a fire environment, as part of the FY02 ASCI Level 1 STS Abnormal milestone.
The Field Portable Gas Analyzer was designed, fabricated, and fielded to obtain internal dew point measurements on W80 warheads while in their stockpile locations. The results uncovered important desiccant properties that allowed a significant extension of the W80 desiccant end-of-life estimate. The budgetary impact of this project has been estimated to be in the tens of millions of dollars, primarily through relaxation of schedule and budget pressures on the W80 Stockpile Life Extension Program.
Plans for this life-extension program drew on the results of a W80 Dual Baseline study, an in-depth assessment of refurbishment options to be completed by Livermore, Los Alamos, and Sandia in FY 2001. The schedule called for the first production unit of the refurbished warheads in FY 2006. As refurbished W80 units enter the stockpile, Livermore will be responsible for continuing evaluations of their performance. Los Alamos will retain this responsibility for W80s not yet refurbished. In addition, pits from Livermore-designed weapons will now be thoroughly examined at facilities for handling special nuclear materials in Livermore's Superblock. These stockpile surveillance activities previously had been conducted at Los Alamos.
The W80 Stockpile Lifetime Extension Program (SLEP) an extensive qualification program to ensure that the W80 meets its operational and nuclear safety requirements in a wide range of environments. W80 refers to the current stockpile weapon system. The W80-3 refers to the upgraded system being developed for the Stockpile Lifetime Extension Program.
The electromagnetic qualification program includes testing a refurbished W80 under a variety of electromagnetic conditions. These include simulations of friendly and hostile radio frequency transmitters, electromagnetic pulse, nearby and direct-strike lightning, accidental contact with electrical power lines, and electrostatic discharge. The electromagnetic qualification program started by characterizing the behavior of the cruise missiles that carry the W80. It is important to characterize the payload bays and warhead interface cables of the Air Launched Cruise Missile (ALCM) and Advanced Cruise Missile (ACM) because the W80 spends time mounted in the cruise missiles for logistical operations and remains in the missile from carriage on a B-52 to launch and delivery.
For the W80 LEP, the NNSA accomplished Phase 6.4 activities including finalization of all design releases and start of Process Prove-In (PPI) activities. The Congressional funding decrease in FY 2006 required the program to be rebaselined; however, a May 2006 Nuclear Weapons Council (NWC) decision to cancel the LEP caused a large portion of the FY 2006 workload to be directed toward bringing the program to an orderly suspension.
This LEP will consider W80-based reuse, refurbishment, and replacement options for nuclear and nonnuclear components for the cruise missile to replace the Air Force’s aging air-launched cruise missile (ALCM). Key design requirements include use of the existing insensitive high explosive design; incorporation of modern components and safety features; maximum use of non-nuclear components developed for other LEPs; and exploration of enhanced surety options.
Even as the United States had foresworn the building of new nuclear weapons, the 2010 NPR provided the latitude and direction to consider the full range of LEPs including refurbishment, reuse, and replacement of the nuclear components. Through the LEPs and alterations (“ALTs"), NNSA extends the capability of weapons that have reached the end of what was anticipated to be their normal lifespan, or that have degraded parts to ensure their continued safety and effectiveness. NNSA accomplishes this objective by conducting extensive surveillance and modernizing, through LEPS, including replacing or repairing nuclear and non-nuclear components, while maintaining operational capability. These tasks require intensive human effort, backed up by DOE’s substantial computational capabilities. Consistent with the 2010 NPR, the United States does not develop new nuclear warheads.
Each year DOE’s NNSA sets forth its plans to maintain the stockpile in the annual Stockpile Stewardship and Management Plan. This plan is a comprehensive, interagency-coordinated plan for NNSA weapons activities that articulates the scope of work and required resources for the next 25 years. It covers in substantial depth the five-year period of the President’s budget request.
A concrete example of how the interdepartmental planning process worked was the decision to accelerate the schedule for the Long Range Stand Off (LRSO) cruise missile warhead. The decision to accelerate LRSO resulted from a detailed and deliberate interagency process that considered the future threat environment. Ultimately, DOE’s NNSA and DOD recommended this acceleration via the NWC and it was approved in the context of the President’s Budget Request for Fiscal Year (FY) 2016. While the Air Force was accelerating the design and development of the new cruise missile, DOE’s NNSA is accelerating the LEP for the W80-4 warhead for the LRSO from a First Production Unit (FPU) date in FY 2027 to FY 2025.
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