The Pantex Plant assembled the “first production capability unit” of the W88 Alt-370 submarine-launched warhead, a precursor to the first production unit intended to prove the entire warhead design is ready for mass production, the Pantex Plant said.

The phrase “first production capability unit” did not appear in official National Nuclear Security Administration (NNSA) documents until this March, when the term debuted in the agency’s 2021 budget request. The agency’s recent Stockpile Steward and Management Plan, an annual declassified summary of ongoing NNSA nuclear modernization work, also did not include the term “first production capability unit,” nor did the NNSA’s 2020 budget request. 

A spokesperson for the Bechtel National-led plant operator Consolidated Nuclear Security (CNS) did not immediately reply to a request for comment about when Pantex completed the first production capability unit. 

W88 Alt-370’s true first production unit — a fully assembled, and potentially deployable warhead that will be disassembled to verify the design is sound and ready for mass production — was delayed to fiscal year 2021 from fiscal year 2019 after the NNSA announced in 2019 that the agency had to replace capacitors intended for use in “three major components” of the weapon.

Capacitors store electrical charges and can be used in detonators and neutron generators, among other things.

B61-12, the upgraded version of the oldest deployed U.S. weapon, was also delayed because of the unsuitable commercial capacitors, which NNSA is replacing with custom units that can last decades more in the field. B61-12’s first production unit slipped from 2020 to 2022, the NNSA said.

Meanwhile, CNS said in its press release on Monday that assembling the “first production capability unit” of the W88 Alt-370 allows the Amarillo, Texas, plant’s “staff to exercise processes to ensure readiness for rate production” of the weapon. W88 is the larger of the Navy’s two submarine-launched, ballistic missile warheads, both of which tip Trident II-D5 missiles carried by Ohio-class submarines.

The NNSA and the Pentagon estimate the W88 Alt-370 will cost about $4 billion over roughly 10 years, including up to $3 billion in NNSA expenses. The NNSA has roughly 350 W88 warheads, the Washington-based, arms-control-advocating nonprofit, Federation of American Scientists, estimates.

Meanwhile, Pantex remains in reduced mission critical operations in an attempt to slow the spread of COVID-19 through the nation’s primary nuclear weapons service hub. CNS told any employee who could telework to do so, but people involved with hands-on nuclear-weapons work are still reporting for the plant’s usual three shifts.

Pantex, like other NNSA sites, has reported cases of COVID-19, the viral disease caused by the novel coronavirus that broke out in Wuhan, China, in 2019. Typically, each confirmed case of COVID-19 sends many more people into preventative quarantine.