Chicago Pile-3

Chicago Pile-3 was the world's first heavy water reactor. It was built in 1943 near Palos Hills, Illinois, on the former and original site of Argonne National Laboratory. It first went critical on 15 May 1944, was used in the experimental physics work of the Metallurgical Laboratory for the Manhattan Project, and was deactivated in 1954.

CP-3 was initially fueled with natural uranium and used heavy water as a neutron moderator. In January 1950, the reactor was dismantled due to suspicion of corrosion of the aluminum cladding that surrounded the control rods. The reactor was rebuilt and redesignated CP-3′ . It was restarted in May 1950 and operated until 1954. The reactor was authorized to operate up to 300 kilowatts. The two versions of the reactor were used to study physics, separate fission products, recover tritium from irradiated lithium, and study radionuclide metabolism in laboratory animals.

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