ALEXANDRIA, Va. — The National Nuclear Security Administration (NNSA) made post-Cold War history in its 2021 budget request this week, requesting funds to develop a new sea-based nuclear warhead designated Mk7 W93 — a weapon designed to be rapidly upgradeable and serviced outside of the Pantex Plant in Amarillo, Texas.
This will be the first new warhead design in decades – specifically, the first since the Cold War that is not a refurbished model of a weapon already in the field.
The planned W93 warhead, which will use a brand new Mk7 re-entry vehicle, could also contribute technology to the parallel development of a new sea-based warhead for the United Kingdom, senior Department of Defense officials said this week.
The weapon would begin life as a submarine launched ballistic-missile warhead, and — as a design based on a device previously tested at yield underground in Nevada — would not require explosive testing to be certified for use by the Pentagon, Charles Verdon, deputy administrator for defense programs at National Nuclear Security Administration (NNSA) headquarters in Washington, said this week.
Verdon discussed some details about the weapon at the ExchangeMonitor’s annual Nuclear Deterrence Summit, held here Tuesday through Thursday.
Other W93 details, however, were scarce at deadline Friday for Nuclear Security & Deterrence Monitor. The NNSA plans “concept and Assessment Refinement activities” for the warhead in 2021, according to a budget in brief issued by the Energy Department this week. Early W93 work could include “[r]esearch and development efforts for critical national capabilities, such as fuses and aero shells,” the head of U.S. Strategic Command said Thursday in congressional testimony.
More W93 details could be forthcoming in the NNSA’s detailed 2021 budget justification, which was not available at deadline.
At the Deterrence Summit this week, the directors of both DOE nuclear weapons design laboratories, the Los Alamos National Laboratory in New Mexico and the Lawrence Livermore National Laboratory in California, declined to say which of their shops would design and develop the warhead.
Asked which of the two facilities would handle the W93, if Congress approves it, Lawrence Livermore Director William Goldsmith said, “good question.”
Los Alamos Director Thomas Mason was similarly evasive.
“There’s always competition,” Mason said from the same dais as Goldstein, where he and his counterpart spoke alongside Sandia National Laboratories Deputy Director Dori Ellis during a panel discussion.
Mason later joked that Los Alamos, which designed the Navy’s current W76-1, W76-2, and W88 submarine-launched ballistic missile warheads, was the “Los Alamos Naval Laboratory.” He also told NS&D Monitor, in a brief interview from the conference floor, that it was his job to make sure Los Alamos wins any competition to design the W93.
Los Alamos is the design agency for the NNSA’s current ongoing nuclear weapon refurbishments — the B61-12 gravity bomb and the W88 Alt-370 submarine ballistic missile warhead. Livermore is the design agency for the two major refurbishments planned after that — the W80-4 cruise missile warhead and the W87-1 intercontinental ballistic missile warhead.
W93 was until recently known as Next Navy Warhead in the NNSA’s declassified plans. Before the Next Navy Warhead, the NNSA called W93 the Interoperable Warhead-2. The agency’s fiscal 2020 Stockpile Stewardship and Management Plan shows a notional 2034 first production date for W93, a notional cost of $14 billion to complete the entire warhead program, and early feasibility studies starting in the current 2020 federal budget year.
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 submarines. The first of 12 Columbia boats is slated to go on patrol in 2031.
Later, according to a source familiar with the proposal for the weapon, W93 could be adapted for other sea-based weapons.
In addition, this person said, the proposed W93 notionally could be serviced by the military at Pentagon-controlled locations. Usually, nuclear weapons coming off deployment for maintenance head to Pantex. Creating an alternative to the plant could potentially shorten the weapon-servicing supply chain.
Meanwhile, the No. 2 official at the Pentagon’s acquisition shop, and the commander of Strategic Command, each said Thursday that W93 could help the United Kingdom develop its own next-generation submarine-launched, ballistic-missile warhead.
W93 will “support a parallel Replacement Warhead Program in the United Kingdom whose nuclear deterrent plays an absolutely vital role in NATO’s overall defense posture,” STRATCOM chief Adm. Charles Richard said in testimony prepared for a Thursday hearing of the Senate Armed Services Committee.
“I think it’s wonderful that the U.K. is working on a new warhead at the same time, and I think we will have discussions and be able to share technologies, but these will be two independent, development systems,” Alan Shaffer, the Pentagon’s deputy undersecretary of defense for acquisition and sustainment, said in a question-and-answer session at the Nuclear Deterrence Summit on Thursday.
The United Kingdom has a purely sea-based nuclear arsenal, comprising nuclear-powered ballistic-missile submarines. The entire U.K. nuclear-weapon program closely mirrors the sea-based leg of the U.S. arsenal, including the Lockheed Martin-built Trident missiles carried by both countries’ boats.
According to The Washington-based Federation of American Scientists, which tracks global nuclear weapons programs, the U.K.’s Trident Holbrook nuclear warhead is “thought to be” a modified, U.S.-designed W76 warhead. W76 is the smaller of the U.S. Navy’s two submarine-launched, ballistic-missile warheads. The W88 is the larger of the pair.
