Accelerating upgrades for the nuclear warhead slated to fly in the next decade on a new air-launched cruise missile would consume the single largest portion of the budget increase proposed for National Nuclear Security Administration (NNSA) nuclear weapons programs in 2019, according to a detailed budget document released Friday.

For fiscal 2019, the semiautonomous Department of Energy nuclear-weapon agency requested more than $650 million for its W80-4 life-extension program: quadruple what the program receives on an annualized basis under the fifth continuing resolution of the current budget year. That would also represent a quarter of the total increase proposed for the NNSA Weapons Activities account in the fiscal year that begins Oct. 1.NNSA logo

The spending spike for the W80-4 life-extension program, which began in 2014 and is slated to wrap up by Sept. 30, 2031, would if granted take up more than a third of the increased funding the NNSA requested in 2019 for Directed Stockpile Work: agency programs within Weapons Activities that deal directly with nuclear warhead production.

The main 2019 product of the increased W80-4 funding would be a W80-4 LEP Weapon Design and Cost Report to help the agency nail down — sometime between the next fiscal year and 2022 — the final cost and schedule of the warhead upgrade, the budget justification says.

The Pentagon is set to choose between new air-launched cruise-missile designs from Lockheed Martin [LMT] and Raytheon [RTN] in the early 2020s, with an eye toward fielding the new weapon with its refurbished warhead later that decade. The Pentagon’s name for the program is Long-Range Standoff Weapon.

The proposed 2019 funding bump for W80-4 warhead work at the NNSA would, according to the Trump administration Nuclear Posture Review released Feb. 2, align DoE warhead refurbishment with the Pentagon contractors’ missile development.

For 2019 Directed Stockpile Work overall, the DoE branch requested more than $4.5 billion: about a 40-percent increase from the current appropriation.

The NNSA released its 2019 detailed budget justification almost two weeks after the White House rolled out its latest proposed budget.

In total, the White House seeks about $15 billion for the agency: roughly a 16-percent increase from the 2018 appropriation, and about 8 percent more even than the $1-billion year-over-year boost the Trump administration sought for the agency in 2018.

Meanwhile, the detailed budget justification included substantially no new details about the NNSA’s plans to develop two new low-yield sea-launched nuclear warheads called for in the Nuclear Posture Review.

On Wednesday at the ExchangeMonitor’s annual Nuclear Deterrence Summit, then-acting NNSA Administrator Steven Erhart — who was replaced Thursday by full-time Administrator Lisa Gordon-Hagerty — said the first of the two warheads addressed in the NPR would be a dialed-down version of the W76 that now flies on Trident II D-5 ballistic missiles carried aboard Ohio-class submarines.

Erhart said the NNSA could decrease the W76’s yield by removing the secondary stage from the thermonuclear warhead. Former NNSA Administrator Linton Brooks, who spoke at the Deterrence Summit on Thursday, estimated such a modification might cost tens of millions of dollars.

The 2019 budget justification did not provide any details about modifying the W76, or even acknowledge this was the agency’s plan.

“The 2018 Nuclear Posture Review states that the United States will modify a small quantity of existing SLBM [submarine-launched ballistic missile] warheads to provide a low-yield option in the near-term,” the NNSA stated in the budget justification. “As the Nuclear Weapons Council translates policy into military requirements, the Administration will work with Congress for appropriate authorizations and appropriations to develop options that support the modification.”

The justification’s paragraph about modifying existing submarine-launched warheads was written under the heading “W76-1 Life Extension Program,” which summarized the final stages of the NNSA’s ongoing program to upgrade the existing version of the warhead for 30 more years of service. The warhead was first deployed to the Navy in 1978. Counting preliminary design and study work, the current W76 life extension began in 2000 and is set to wrap up in fiscal 2019.

Meanwhile, the 670-plus-page budget justification released Friday sheds very little light on NNSA plans for future plutonium pit production. The Pentagon says it needs NNSA to produce 80 of these nuclear-weapon cores a year beginning in 2030. Last year, the NNSA said it will make 30 a year at the Los Alamos National Laboratory, but that it might make some or all of the remaining 50 annually at the Savannah River Site in Aiken, S.C.

The budget justification released Friday says only that the NNSA wants an unspecified amount of funding in 2019 for “[o]ther project costs associated with pre-conceptual design efforts supporting the selection of a single preferred alternative for plutonium pit production beyond 30 war reserve pits per year.”

Officials are exploring whether DoE could convert the Mixed Oxide Fuel Fabrication Facility under construction at Savannah River into a pit plant. The facility is being built to dispose of surplus U.S. weapon-grade plutonium under an arms-control pact finalized with Russia in 2010, but the NNSA has proposed other ways of getting rid of the material.

Pit production is slated to ramp up in stages, albeit rapidly, beginning next decade at the Los Alamos National Laboratory. The northern New Mexico lab is scheduled to produce 10 pits a year in 2024, 20 a year in 2025, and 30 a year in 2026, Kelly Cummins, NNSA associate assistant deputy administrator, said Thursday at the Deterrence Summit.

As always, Congress must approve the president’s funding request. The House Appropriations energy and water development subcommittee, which has first crack at drafting DOE’s budget each year, had not scheduled a hearing on the agency’s 2019 request at deadline Friday for Nuclear Security & Deterrence Monitor.