This book, like the one I wrote about yesterday, is a horror story for engineers. Idaho Falls is about the SL-1, a prototype nuclear reactor in the desert in Idaho. Although it had been designed for a 3 MW thermal capacity, in early 1961 its output briefly reached something like 18 GW when the single main control rod was pulled too far out of the core. This power surge caused the reactor to explode, killing its three operators and necessitating an elaborate cleanup effort and a painful investigation.

Idaho Falls paints a terrifying picture of the SL-1. Apparently it was poorly designed (single primary control rod, no containment vessel) and also had deteriorated significantly over time: not only would the control rods stick sometimes, but also the proper placement for the rods kept changing as neutron-absorbing boron flaked off of the reactor. Furthermore, oversight was limited and operating procedures were poorly documented.

A large part of Idaho Falls focuses on the people involved; this adds human interest, but in the end there is no convincing evidence that personality issues were a direct contributor to the reactor explosion. There is, however, an excellent anecdote describing what may be the least funny practical joke of all time: an operator (one of the three who was later killed in the explosion) turned off a fan that cooled part of the reactor and watched his colleagues panic for a while before reaching behind a control panel and switching it back on.

I came across this book in an indirect way: last summer, while driving across the Lost River Desert on the way to Borah Peak, I saw an interesting collection of buildings. A sign pointed to the Idaho National Laboratory, which I’d barely even heard of. After getting home, I read up a bit on this lab and eventually found a reference to Idaho Falls. It’s a quick read that people interested in the very early nuclear age should enjoy.