Replacement of Neutron Generators is Routine

At a town hall meeting this week in Oak Ridge, Tennessee, near the proposed location of the new “UPF” nuclear weapons facility at the Y-12 National Security Complex, the state’s junior senator, Bob Corker quipped:

It’s just about the fact that our nuclear arsenal is absolutely obsolete. I saw neutron generators, literally, out in New Mexico that will quit working in the year 2015, which means it renders the weaponry totally obsolete.

Whew. Stunning.

Neutron generators are “limited life components” (LLCs). The NNSA FY 2012 Congressional Budget Request has this to say: Many age-related changes affecting various nuclear warhead components are predictable and well understood. Limited life component exchanges are performed routinely to replace these components periodically throughout the lifetime of the weapon. Components such as power sources, neutron generators and tritium reservoirs deteriorate predictably and must be replaced before their deterioration adversely affects function or personnel safety. Page 50, emphasis added.

Changing out neutron generators in fact appears so routine that it seems the military changes them out in the field. A July 1995 Bulletin of the Atomic Scientists (p. 78) mentions “On April 11, [1995] Sandia delivered 36 recertified neutron generators to the Navy…” Emphasis added.

NNSA says under FY 2010 Accomplishments for Stockpile Systems: “Delivered all scheduled LLCs (GTS [gas transfer systems, meaning tritium] reservoirs and neutron generators (NG)) and alteration kits to the DoD and Pantex to maintain the nuclear weapons stockpile.” NNSA FY 2012 Congressional Budget Request (CBR), p. 61, emphasis added.

Also of interest on the same page: “Selected a common NG for the B61 and B83 that will reduce development, production, and maintenance costs.”

Neutron generators are testable, and the testing devices themselves are being improved. “FY 2010 Accomplishments Stockpile Readiness Nonnuclear Readiness… Deployed Neutron Generator (NG) Testers, which assures neutron generator test capability by modernizing testers as required to support NG production and shelf-life programs.” NNSA FY 2012 Congressional Budget Request, p. 135.

A MC4380 Neutron Generator for the W76-1
Neutron Generator, Sandia Lab News, March 2011

In the current Life Extension Program W76-1’s are being outfitted with new-design neutron generators (the MC4380). Corker is seeing neutron generators in New Mexico because Sandia produces them and loads tritium into the neutron target tubes that are a critical part of neutron generators. Production of neutron generators is being both improved and expanded.

This from Sandia Labs “Labs Accomplishments:”

During FY10, Sandia shipped more than twice as many neutron generator assemblies (NGAs) to its NNSA and military customers than in any previous year. This totaled 850 NGAs and 340 packaging requirement kits. Record completion rates were achieved in four different production areas within the neutron generator supply chain, in concert with a shift to a common neutron generator subassembly that improved production efficiency. Sandia established a balanced supply chain capacity approach to help meet future NG directive schedule challenges with a diverse neutron generator product mix supporting numerous weapon systems., p. 5

Neutron generators themselves are being continuously improved, for example:

In the early 1990s Sandia undertook to design a replacement neutron generator for the W76 nuclear warhead on the Mark 4 reentry body of the Navy’s Trident I system. There were several compelling reasons for doing so, including the need to increase the component’s design margins, simplify its manufacturability, augment its resistance to new profiles of hostile environments, and increase its life span.

In 1999 the MC4380 Neutron Generator and its MC4378 Timer, MC4705 Voltage Bar, MC4148 Rod, MC4437 Current Stack, and MC4277 Neutron Tube were qualified for use in the Navy’s W76 weapon system. This culminated a multi-year development effort which included the transfer of production capability from the Pinellas Plant to Sandia. This is the first weaponized neutron generator to employ a focused ion-beam neutron tube for higher reliability, the first produced at Sandia, and the first Sandia component with radiation hardness requirements to be qualified without underground testing.

The neutron generator business is very robust, and Corker’s claims of obsolescence are absurd.