Word: pilings
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Dates: during 1940-1949
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These radiations are not peculiar to atomic bombs. They are also produced by the controlled chain reaction in a uranium pile or atomic power plant. The reaction itself generates powerful gamma rays and floods of neutrons. The uranium disintegrates, leaving a residue of highly active fission products. The neutrons, wandering through the pile, the cooling system and the concrete shield, stir up radioactivity. The pile may become "poisoned," and everything from it, or in contact with it, must be shunned like death...
Several approaches were guessable. A small plutonium pile might serve as a source of heat to drive some conventional engine, using steam or other fluid as a heat-transfer agent. More radical, and probably more interesting to imaginative technicians, would be a motor using atomic energy direct. This would be possible if "fissionable material" could be made to "explode slowly" like the propellent material in a bazooka projectile. The products of the slow explosion would have to stream out in one direction, giving a powerful, sustained push in the opposite direction. The obstacles blocking either approach were admittedly enormous. "Even...
Inclosed in graphite blocks inside the pile, aluminum cans of various chemicals were being exposed to neutrons, which transmuted some of their atoms into radioactive isotopes. To extract such a can, the pile must be shut down by remote control lest a beam of neutrons follow through the aperture and wipe out the operators...
Enclosed in a white-and-green building the shielded pile looked like a mighty concrete block. A red light warned that it was working. Behind the massive walls, a blizzard of darting neutrons was smashing atomic nuclei, creating hundreds of radioactive isotopes so "hot" that invisible specks of them could kill. All around were vigilant Geiger counters ready to raise the alarm if too much radiation leaked. But the only sound was the hum of the ventilating system carrying deadly gases up the stack...
Then the scientist nodded to TIME's correspondent. "Turn the switch." The switch looked like a valve on a gas stove, it turned easily. Control rods (probably of cadmium) clanged into place. They soaked up the vital neutrons faster than they were produced from the uranium. The pile stopped...