April 18, 2024

A key component of the US nuclear deterrent has reached a major milestone as production of the first upgraded W88 Alt 370 nuclear warhead is completed. Developed by Sandia National Laboratories, the Kansas City National Security Campus, the Y-12 National Security Complex, Los Alamos National Laboratory, and Pantex, the upgraded warhead gets an improved arming mechanism, or “brain”, as part of the program to extend its service life.

Since its deployment in 1989, the 475-kiloton-yield W88 fusion warhead has been a critical component of the US Trident II nuclear missile submarine fleet. Representing a vital third of the American nuclear defense triad, this Cold War relic has surpassed three decades in service and is urgently demanding refurbishment and modernization.

Much of the updating effort involves replacing materials that have deteriorated over the years, including the nuclear elements, the explosives needed to implode the fission detonator, and the polymer foam that holds the hydrogen isotopes that fuels the main explosion. In addition, many of the components need upgrading to keep pace with multiple advances.

A key system is the Arming, Fuzing, and Firing (AF&F) system that Dolores Sanchez, senior manager of the W88 Alteration 370 for Sandia, describes as the “brains of the warhead.” In fact, it’s much more than that. The AF&F is the difference between the W88 being a nuclear weapon and a radioactive lump of iron.

The AF&F assembly is the system that receives and confirms the GO code from the US President, then reconfigures the bomb’s mechanism so it’s possible for it to nuclear detonate and unlocks the firing system. However, the warhead still remains inert until the missile it sits atop is launched. The AF&F then confirms that the launch was authorized and analyzes factors like acceleration and time of flight to make sure the warhead isn’t fully armed until it’s a safe distance away from the submarine and on course to its target.

According to Sandia, the first production unit of the W88 Alt 370 was assembled by Kansas City National Security Campus in May and was then sent to Pantex for insertion of explosives and final assembly in early July before being shipped to the US Navy. Along with the AF&F assembly, the upgrade included radar, communication, guidance and other safety and security components.

The upgrade included inert versions of the warhead being used for tests, including flight, impact, vibration, drop, extreme temperature, and massive electrical impulse tests.

Source: Sandia National Laboratories