The Department of Energy’s National Nuclear Security Administration (NNSA) completed the first production unit of the W76/Mk4B reentry body for the Navy’s submarine-launched ballistic missile warhead, the agency said Wednesday.
The first unit was produced nearly three months ahead of schedule, according to an email from NNSA. The Mk4B reentry body, developed in coordination with the Navy, is designed to protect the W76 warhead during atmospheric reentry, or the process of an object entering the atmosphere at extreme speeds. The Mk4B will also replace the earlier Mk4A variant.
“NNSA is making good on our commitment to accelerate production for the nation’s nuclear deterrent and delivering the first W76/Mk4B to the Navy ahead of schedule,” NNSA Administrator Brandon Williams said in a statement. “As a former nuclear submarine officer, I have a special appreciation for the sea leg of our triad, which is essential to our assured second-strike capability. Enhancing the reliability of the W76’s reentry body will help ensure the reliability of the deterrent and strengthen America’s national security more broadly.”
The W76 warhead is deployed aboard the Navy’s Trident II D5 submarine-launched ballistic missile as a component of the nation’s nuclear triad.
NNSA said the accelerated schedule was enabled by coordination across the nuclear security enterprise, including the Pantex Plant, the Kansas City National Security Campus, Sandia National Laboratories and Los Alamos National Laboratory.
The Pantex Plant leveraged a previous readiness determination conducted for the W76-1 program, while Kansas City completed key non-nuclear components ahead of deadline. Sandia and Los Alamos issued qualification evaluation releases to support the accelerated timeline, NNSA said.
NNSA Deputy Administrator for Defense Programs David Beck described the milestone as evidence of the agency’s ability to meet “critical national security needs.”
Future sea-based modernization programs include the W88 Alteration 376, the W93 warhead and the W80-5 warhead for the planned nuclear-armed sea-launched cruise missile, all expected to reach first production in the early-to-mid 2030s.