The Department of Energy made post Cold War-history in its 2021 budget request, which seeks funds to develop a new sea-based nuclear warhead designated Mk7 W93 — a new warhead designed to be rapidly upgradeable, and serviced outside of the civilian agency’s Pantex Plant in Amarillo, Texas. 

It will be the first new warhead design in decades: the only one since the Cold War that is not a refurbished model of a weapon already in the field.

The W93 was most recently known as the Next Navy Warhead in the DoE’s declassified plans, and as the Interoperable Warhead-2, prior to that. The fiscal year 2020 year Stockpile Stewardship and Management Plan published by DoE’s semi-autonomous National Nuclear Security Administration’s (NNSA) shows a notional 2034 first production date for W93, with early feasibility studies starting now, in fiscal 2020.

The weapon would be based on a design already test fired underground at the Nevada National Security Site before yield tests ended in the 1990s, according to someone with knowledge of the proposal for the weapon. It would initially be suitable for use on submarine-launched intercontinental ballistic missiles, but could potentially be tweaked for use on other sea-based weapons, this person said.

To begin, W93 would tip the eventual successor to the Navy’s Trident II D5 submarine-launched ballistic missile, which would be carried through the 2080s by the next-generation Columbia-class ballsitic missile submarines. The first Columbia is slated to go on patrol in 2031. The United Kingdom’s nuclear weapons are also delivered via Trident missiles.

The 2020 Stockpile Stewardship and Management Plan notionally calculated the NNSA’s share of development at an inflation-adjusted $14 billion.