Interview with Thomas A. Tombrello - Caltech Oral Histories

Tombrello–178
without crossing anything that was trouble, although I realized that the streets perpendicular to
the ones I was on were totally blocked. It was an interesting experience.
But the committees moved along, and I’m going to telescope it all, because, you know,
the details don’t matter too much. The lab continued to evolve, and I kept evolving the
committee. The only thing that didn’t change was that I continued to chair both of them.
Associate directors that ran that directorate changed, and the nature of the committees changed.
At one point, the chemistry committee had to pick up nuclear chemistry, and you couldn’t really
do nuclear chemistry unless you dealt with the classified issues. The nuclear chemistry group
basically was the group that did what were called secondary diagnostics. I guess it’s no big
secret that a thermonuclear weapon is a primary fission weapon that then detonates the
secondary, which is the fusion weapon. I won’t go any further, because you can find all kinds of
crap on the Web, and I can’t even comment on the accuracy of the stuff on the Web about it. But
the secondary diagnostics mean you’re looking at radioactive materials from both the bomb itself
and from little markers you put in there to tell you what’s actually going on in this explosion. A
subset of the committee had to be cleared, and we separately wrote a report about that, which
then went through the declassification process and was incorporated into the main report. So that
was the beginning of the fact that the committee was going to deal with classified material. As
things continued, it got more and more important that the other 90 percent of the iceberg get
looked at. The committees had to be completely cleared for security. Eventually, it became
slightly embarrassing that I had been doing this for not quite twenty years, and so I stepped off
the stage.
ASPATURIAN: What year would this have been?
TOMBRELLO: 2006, 2007, somewhere in there. I still was on some other committees and got
pulled in on a lot of ad-hoc committees. Ad-hoc committees plus red teams. Red teams are an
interesting exercise. I’ve done that for JPL, and I’ve done it for Livermore. It’s usually when
you want to find out why something went wrong that you form these committees, and I believe
JPL calls them tiger teams. At Livermore they’re red teams—no political connotation. You’re
supposed to meet as an ad-hoc committee, come to a conclusion, and write a report, which is
handed to somebody farther up the line. In the summer of 2008, I was chair of a red team on
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