New Hot Laboratory Facilities which support three major research programs directed by the Los Alamos Scientific Laboratory of the University of California are described. For the Nuclear Rocket Propulsion Program, a hot cell addition to the Radio Chemistry Building at Los Alamos will be completed early in 1963, and construction is expected to start soon on the hot cell addition to the Maintenance, Assembly and Disassembly Building at the Nuclear Rocket Development Station in Nevada. Integral hot laboratories are designed in the facilities for the Ultra High Temperature Reactor Experiment and the Fast Reactor Core Test at Los Alamos. (auth)

Abstract: Two nuclear accidents involving a plutonium sphere just subcritical in size occurred at the Los Alamos Laboratory, LA-1 in 1945 and LA-2 in 1946. Because remote control devices were deemed unreliable at the time, the tamper material (tungsten carbide bricks in LA-1 and beryllium hemispheres in LA-2) was added by hand with the operator standing next to the assembly. In each case the critical size of the assembly was accidentally exceeded and the resultant exponentially increasing chain reaction emitted a burst of neutrons and gamma rays. Ten persons were exposed to the radiation bursts which were largely composed of neutrons. The doses ranged from fatal in the case of the two operators, to small in the case of some survivors. The two operators died within weeks as a result of acute radiation injury. Only six of the eight survivors were available for follow-up study ten or more years after the accident. Four of these six survivors are now dead, but the two living survivors are in excellent health with no clinical or laboratory evidence of late radiation injury. Two of the deceased died of acute myelogenous leukemia, another died at age 83 of refractory anemia, and the fourth of …

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