A civil-military panel approved designs for an upgrade of the W88 nuclear ballistic missile warhead carried aboard U.S. submarines, the National Nuclear Security Administration (NNSA) said Jan. 16.

Panel members, drawn from within and outside of the Department of Energy agency, approved system-level designs for the W88’s upgraded arming, fuzing, and firing (AF&F) subsystem on Dec. 14, an NNSA spokesperson in Washington told our sister publication Weapons Complex Morning Briefing.logo-nnsa-top

The AF&F system includes non-nuclear mechanical components and the conventional high explosives that would help trigger a nuclear chain reaction if the weapon is used. W88 warheads are deployed on Trident II D5 missiles loaded onto Ohio-class submarines.

The NNSA’s official name for this warhead upgrade is the W88 Alteration 370 program, which began in 2012. The agency plans to produce the first upgraded warhead in Dec.2019 and the last in 2024. According to Tuesday’s press release, the NNSA remains on target to hit those milestones.

There are roughly 400 W88 warheads in the U.S. arsenal, according to GlobalSecurity.org. The U.S. first deployed the weapon in 1988 and plans to spend more than $2.5 billion upgrading it over the life of the Alt 370 program, according to the 2018 Stockpile Stewardship and Management Plan the NNSA published in November. The program had about a $280-million budget in fiscal 2017.