23 September 1983 - An operator error during a fuel plate reconfiguration in an experimental test reactor led to an excursion of 3×1017 fissions at the RA-2 facility. The operator absorbed 20 Gy of gamma and 17 Gy of neutron radiation which killed him two days later. Another 17 people outside of the reactor room absorbed doses ranging from 350 mGy to less than 10 mGy.