In Radiation Safety History
On July 23, 1956 an overexposure occurred at the Materials Testing Reactor
(MTR) at Idaho Falls, Idaho. During a scheduled refueling outage, six
employees were working on the reactor top adjacent to the reactor tank
opening, while two men were present as observers and advisors. All were
exposed to radiation when a highly radioactive reactor component was
placed in a position where it was not adequately shielded because of
lowered water level in the reactor tank. The moving of the component
and the coincident lowering of the water level were done to facilitate
insertion and removal of experiments in the reactor.
The eight employees received radiation exposures, ranging from 2.5 rem
to 21.5 rem.