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Why was Chicago Pile-1 important in the history of nuclear power?

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Labeled diagram showing the process of a nuclear power plant with a pressurized-water reactor. Water circulates through the reactor core, heats to produce steam in a steam generator, which drives a turbine connected to an electric generator. Steam is then cooled in a condenser using water from a cooling tower, which releases nonradioactive water vapor. Control rods, pumps, and transmission lines are also indicated. — nuclear power Schematic diagram of a nuclear power plant using a pressurized-water reactor.

Chicago Pile-1 (CP-1) was a landmark in the history of nuclear power because it achieved the world's first self-sustaining nuclear chain reaction on December 2, 1942.12

Constructed by a team led by Enrico Fermi under the football stands at the University of Chicago, this experimental reactor proved that the controlled release of atomic energy was feasible. Its success was critical to the Manhattan Project, as it demonstrated the fundamental principles necessary for two primary wartime goals: the development of atomic bomb designs and the production of plutonium.23

By validating the use of graphite as a moderator for uranium fuel, CP-1 provided the essential proof of concept that paved the way for the construction of larger, high-power production reactors and the eventual evolution of nuclear technology for both military and civilian energy applications.23