Dealing with a debacle: A better plan for US plutonium pit production

Bulletin, By Curtis T. Asplund, Frank von Hippel | April 27, 2023

For two decades, the Pentagon and Congress have been increasingly concerned that the United States does not have a reliable capability to produce plutonium “pits,” the cores of US thermonuclear warheads. In 2018, the agency responsible for the production and maintenance of US nuclear warheads, the National Nuclear Security Administration (NNSA), responded with a plan to build, on a crash basis, pit production lines in New Mexico and South Carolina at the same time, with a combined production capacity of 80 pits per year.

One of the production lines is in an advanced state of installation at the Los Alamos National Laboratory in New Mexico, the home of US pit-production expertise. The other is to be installed at the Department of Energy’s Savannah River Site (SRS) in South Carolina, where there is no pit-production expertise, in a massive building that the Department of Energy built for another purpose and was then forced to abandon because of huge cost overruns. South Carolina’s congressional delegation, led by Sen. Lindsey Graham, successfully prevailed on the Trump administration to repurpose this $6 billion building—once known as Mixed Oxide Fuel Fabrication Facility and intended to downblend surplus military plutonium for use as commercial reactor fuel—to plutonium pit production. History is repeating itself, however. The NNSA’s cost estimate for using the Savannah River facility to manufacture warhead pits has already risen from $3.6 billion in 2017 for an 80 pit-per-year production capacity to $11.1 billion for a 50 pit-per-year capacity in 2023.

The NNSA’s rationale for its ambitious pit production program is, to say the least, questionable. The agency proposes to first build 800 pits for new US intercontinental ballistic missile (ICBM) warheads, which would be needed only if the US decides to increase the number of warheads on each missile from one to three. Previous US administrations have considered such uploading destabilizing; silo-based ICBMs are targetable and increasing the number of warheads they each carry would make them more attractive targets. Loading the ICBMs with more warheads would also make compliance with the New START arms control agreement with Russia extremely difficult, should that agreement be extended in 2026.

After producing the ICBM warheads, the NNSA plans to replace all 1,900 US submarine-launched ballistic missile warheads with new warheads, equipped with what is known as insensitive high explosive, which is shock resistant and therefore less susceptible to accidental explosions that could disperse a warhead’s plutonium. No such accident has ever happened with ballistic missile warheads, and it is unclear how much this program would actually improve safety. The warheads in the Trident II missile used by US submarines are located near the missile’s third stage, which carries propellant that is as detonable as conventional explosive.

There is also another concern about the NNSA’s plans: The designs of new warheads in which new plutonium pits would be used may depart from designs that have been previously tested. This could result in demands to resume explosive testing, which would undermine the moratorium on nuclear testing that has been observed by all nuclear-weapon states (other than North Korea) since 1998.

Given these questionable production plans and the already out-of-control cost and schedule of the Savannah River pit production facility, and because the remaining life expectancy of the pits in current US warheads is at least 60 years and perhaps much longer, we propose that the Savannah River facility be put on hold and that the Los Alamos program be focused on demonstrating reliable production of 10 to 20 pits per year. Such a demonstration production line would establish that the United States has the capacity to produce pits and would reduce the time required to build additional production lines, if they are needed.

The NNSA should also renew research programs at the Livermore and Los Alamos Laboratories to study the aging of the already existing plutonium pits in the US arsenal and also the older pits from retired warheads. ……………………………………………………………………………….. more https://thebulletin.org/2023/04/dealing-with-a-debacle-a-better-plan-for-us-plutonium-pit-production/