[fr0sty]

This accident? https://en.wikipedia.org/wiki/SL-1

"Stationary Low-Power Reactor Number One, also known as SL-1 or the Argonne Low Power Reactor (ALPR), was a United States Army experimental nuclear reactor in the western United States at the National Reactor Testing Station (NRTS), later the Idaho National Laboratory, west of Idaho Falls, Idaho. It experienced a steam explosion on the night of January 3, 1961, killing all three of its young military operators, and pinning one of them to the ceiling of the facility with a reactor vessel plug. The event is the only reactor accident in U.S. history that resulted in immediate fatalities.