The Chicago pile, also called cp-1, was the first self sustaining, controlled nuclear chain reactor. It was a giant step forward in the development of nuclear energy, and was taken by a group of European scientists who had come to the us when world war ll broke out.
Forty nine scientists, led by enrico Fermi, were present on a converted squash court at the university of chicago’s abandoned stagg field on December 2 1942, when the world’s first nuclear reactor went critical.
After the reactor has sustained the chain reaction for 28 minutes the operators pushed in a cadmium control rod called zip, which absorbed neutrons, and ended the chain reaction.
In 1943, cp-1 was dismantled, and moved to a less-populated site.