ONE of the nation’s most consistently challenging scientific and engineering endeavors is the National Nuclear Security Administration’s (NNSA’s) Stockpile Stewardship Program. This science-based effort, now in its 24th year, is dedicated to ensuring the safety, security, and effectiveness of the nation’s nuclear weapons. The program’s record of outstanding success has resulted from the capabilities provided by high-performance computing (HPC), one-of-a-kind experimental research facilities, and the expertise of dedicated stockpile stewards at the NNSA national security laboratories and production organizations.
One of stockpile stewardship’s most critical elements is the life-extension program (LEP), which extends the life of a warhead by 30 years through replacement or refurbishment of components essential to safety, security, or reliability. LEPs address issues that could lead to degradation of a weapon’s performance. Such issues are discovered through routine surveillance and annual stockpile assessments and are often due to aging effects as weapons remain in the stockpile long after their originally designed lifetimes.
As the feature article, Life-Extension Programs Require Outstanding Resources and Partnerships, describes, Lawrence Livermore is actively engaged in an LEP for refurbishing the W80-1 warhead carried on the U.S. Air Force Air-Launched Cruise Missile (ALCM). The resulting W80-4 warhead will be deployed in the ALCM’s replacement, the Long-Range Standoff (LRSO) missile. The W80-4 is the first U.S. warhead LEP for use with a new Department of Defense (DOD) carrier since nuclear testing ended in 1992. As a result, an important aspect of the LEP is adapting the refurbished warhead to the LRSO missile. An added complexity is that the missile is still being designed, requiring close cooperation between Lawrence Livermore and the Air Force, as well as the two contractors vying to build the LRSO. In that respect, success requires maintaining strong partnerships with the DOD, Sandia National Laboratories (our LEP partner), and NNSA.
The W80-4 LEP effort requires the full array of NNSA’s computational, experimental, and manufacturing capabilities to meet all the prototyping, proof-of-concept testing, and certification requirements. The LEP takes advantage of Livermore’s HPC resources to produce simulations that provide a computational surrogate for nuclear testing by modeling nuclear weapon systems with extraordinary temporal and spatial resolution.
Experiments at Livermore and other NNSA facilities play an essential role in providing the data needed to improve computational models used in LEPs. For example, National Ignition Facility (NIF) experiments offer valuable data for validating LEP design options prior to implementation. The largest and most energetic laser in the world, NIF is NNSA’s preeminent high-energy-density stockpile stewardship experimental facility. Livermore’s world-class experimental facilities also include the High Explosives Applications Facility (HEAF) as well as high explosives synthesis and testing facilities at our remote Site 300. Other resources at Site 300 that support LEP activities include the Contained Firing Facility, the largest indoor firing chamber in the nation.
Livermore materials scientists are mindful that some NNSA manufacturing processes are five decades old, and sustaining these legacy processes for producing LEP components presents an increasing challenge. Livermore scientists search for new processes to manufacture replacements that are less expensive, more environmentally friendly, simpler to certify, and can meet ambitious production schedules. We are working with NNSA production facilities such as the Kansas City National Security Campus to explore the potential of advanced manufacturing technologies to meet modern requirements.
While work continues on the W80-4 at a rapid pace, we anticipate resuming the W78 replacement program, which was paused five years ago to accelerate the W80-4 LEP. Clearly, Livermore stockpile stewards will be fully occupied for the next several years ensuring we meet the goals of both the W80-4 LEP and W78 replacement program. We look forward to working closely with Sandia, DOD, and the NNSA production organizations over the next decade as the W80-4 warhead and the W78 replacement warhead take shape.