The W93 submarine-launched ballistic missile warhead, the first in decades that is not a refurbishment of a weapon already sailing the seas, will be in line for a big budget increase if Congress goes along with the Biden administration’s fiscal year 2023 budget request.

W93, led by the Los Alamos National Laboratory, would see its budget more than triple to over $240 million in fiscal 2023 from more than $70 million in fiscal year 2022, according a small budget-summary document known as a statistical table

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Proportionally and by raw dollars, that is the single largest requested increase for any single nuclear-weapon system in the National Nuclear Security Administration’s (NNSA) Stockpile Major Modernization portfolio: the part of the budget that pays for refurbs of deployed weapons and, in W93’s case, development of new ones. 

W93 will be based on a nuclear-explosive design tested underground at full yield at the Nevada National Security Site before the U.S. moratorium on full-up nuclear explosive tests began in 1992. It will also use a Mark VII warhead to be developed by the U.S. Navy and will be the basis for key parts of the United Kingdom’s next submarine-launched ballistic missile warhead.

The U.K.’s nuclear arsenal includes only submarine-launched ballistic missiles. The current version, the Holbrook, is a modified version of the U.S. W76 warhead: one of two, along with the W88, that the U.S. now fields. The Kingdom last year announced it would increase its warhead cap on the submarines to 260 from the previous target of 180.

In its most recent Stockpile Stewardship and Management Plan, the NNSA said it would produce the first proof-of-concept W93 in 2034 or 2036. That so-called first-production unit is a test article that will be scrutinized by weapons experts to prove the design is war-ready and suitable for mass assembly at the Pantex Plant in Amarillo, Texas.