B61 computer simulation. Image credit: Sandia National Laboratory

Growing up in Albuquerque, New Mexico during the Cold War meant that I had a lot of friends whose parents worked at Sandia National Labs (SNL) doing “nuclear bomb things”, or whatever vague description they’d get out of their parents about what was paying the bills. Things are somewhat more transparent these days, of course. For example, without revealing anything classified, the lab and the NNSA regularly provide updates on various LEPs; this year, SNL revealed some specifics regarding their refurbishment work on the B61 mod 7 and 11.

Over the past year or so, the B61 has been a topic of interest for several reasons. For one thing, the B61 was a prominent star in the 2010 Nuclear Posture Review, which mentioned plans for “a full-scope B61 LEP study and follow-on activities”, as well as the intention to make the F-35 Joint Strike Fighter capable of carrying it.

The B61 also features significantly in the NNSA’s FY 2011 budget, as Kingston Reif explains over at the Nukes of Hazard blog. Reif draws a number of conclusions, particularly that the proposed LEP study will be “major”, and will be designed to streamline the different B61 mods into the B61 mod 12; if you want to get down in the weeds about the B61 mod 12 LEP and some of the background involved, check out Jeffrey’s post from 2008.

Regarding SNL’s role in B61 refurbishment, we can always count on John Fleck of the Albuquerque Journal to get some good tidbits. Recently, he interviewed Dr. Paul Hommert, the director of SNL. The interview itself doesn’t reveal all that much; it’s Fleck’s follow-up on his blog that should get some good wonk discussion going.

Fleck points out that in his July 15, 2010 testimony before the Senate Armed Services committee, Hommert said:

[W]e find ourselves in a state of urgency, with a demanding schedule and expansive product requirements. The primary driver for the schedule of the B61 LEP is the fact that critical nonnuclear components are exhibiting age-related performance degradation. For example, the radar in the B61, which includes the now infamous vacuum tubes, must be replaced. In addition, both the neutron generator and a battery component are fast approaching obsolescence and must be replaced. A secondary driver for the schedule is the deployment of the F35 Joint Strike Fighter, which requires a new digital interface for the B61. Replacing the three aging components and adding the new digital interface represent the absolute minimum approach to this LEP. However, it is my judgment that we need to approach this LEP with a resolute commitment to replace old nonnuclear components and field a nuclear weapon system that employs modern technologies to improve safety and security and to extend service life.

(Bold emphasis mine.)

Fleck then shares with us what SNL’s former Vice President of Technical Support,Bob Peurifoy, told him via email, on the record:

Regarding radars: The B61 Mod 7 used to use a vacuum tube radar. As of my last interaction with Sandia, that vacuum tube radar was showing no aging problems. Something must have changed. During the Mod 7 production run, vacuum tubes became scarce, and I believe the B61 Mod 7 adapted the B83 solid state radar. As I recall, the solid state radar was not age-stable, and at least one retrofit was necessary.

Neutron generators contain tritium. Tritium undergoes radioactive decay, with a half-life of about 12.5 years. It has been necessary, therefore, to replace neutron generators periodically during scheduled maintenance. This is not something new and used to be planned for. No sense of urgency there.

Regarding a ‘battery component’: when I left Sandia, thermal batteries, by all accelerated aging tests, had an infinite life. Hommert’s use of the term “battery component” may refer to an RTG used in the B61 Mod 3 and 4. The RTG used plutonium-238 as a heat source. Its anticipated life was about 25 years. This has been known since 1979. Again, I don’t understand the use of “sense of urgency.”

Being skeptical of the design labs’ management integrity, I’m suspicious that the real reason for the “urgency” is budget-related.

So, this all leads to the question: how “urgent” are the problems that Hommert lists? Obviously, Peurifoy thinks that Hommert is overstating the case as part of a bid for, shall we say, “nuclear pork”. Were these problems there all along and weren’t remedied, so they actually are urgent, or is Peurifoy on the right track here?

Let’s do some brainstorming. What do you think?