Warhead “Super-Fuze” Increases Targeting Capability Of US SSBN Force

The MC7400 AF&F unit on the new W76-1/Mk4A warhead contains a super-fuze that dramatically increases its hard target kill capability. Image: Sandia National Laboratories

By Hans M. Kristensen

Under the cover of an otherwise legitimate life-extension of the W76 warhead, the Navy has quietly added a new super-fuze to the warhead that dramatically increases the ability of the Navy to destroy hard targets in Russia and other adversaries.

In a new article in the Bulletin of the Atomic Scientists Matthew McKinzie from NRDC, Theodore A. Postol from MIT, and I describe the impact of the super-fuze on the targeting capability of the US SSBN force and how it might effect strategic stability.

The new super-fuze dramatically increases the capability of the W76 warhead to destroy hard targets, such as Russian ICBM silos.

We estimate that the super-fuze capability is now operational on all nuclear warheads deployed on the Navy’s Ohio-class ballistic missile submarines. The new fuze has also been installed on warheads on British SSBN.

“As a consequence, the US submarine force today is much more capable than it was previously against hardened targets such as Russian ICBM silos. A decade ago, only about 20 percent of US submarine warheads had hard-target kill capability; today they all do.”

The new article builds on previous work by Ted Postol and myself but with new analysis explaining how the super-fuze works.

In the article we conclude that the SSBN force, rather than simply being a stable retaliatory capability, with the new super-fuze increasingly will be seen as a front-line, first-strike weapon that is likely to further fuel trigger-happy, worst-case planning in other nuclear-armed states.

Read full article here: Hans M. Kristensen, Matthew McKinzie, Theodore A. Postol, “How US nuclear force modernization is undermining strategic stability: The burst-height compensating super-fuze,” Bulletin of the Atomic Scientists, March 1, 2017.

Previous writings about the super-fuze:

• Theodore A. Postol, “How the Obama Administration Learned to Stop Worrying and Love the Bomb,” The Nation, December 10, 2014.
• Hans M. Kristensen, “British Submarines to Receive Upgraded US Nuclear Warhead,” FAS Strategic Security Blog, April 1, 2011.
• Hans M. Kristensen, “Administration Increases Submarine Nuclear Warhead Production Plan,” FAS Strategic Security Blog, August 30, 2007.
• Hans M. Kristensen, “Small Fuze – Big Effect,” FAS Strategic Security Blog, March 14, 2017.

This publication was made possible by a grant from Carnegie Corporation of New York and Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author.