CP-1 and CP-2

Following the successful chain reaction experiment on December 2, 1942, Met Lab scientists continued further experiments on the CP-1 reactor. At the end of February 1943, CP-1 was dismantled so that the materials forming the reactor could be moved to Site A, a secure location in Cook County’s Argonne Forest Preserve twenty miles southwest of Chicago. There the reactor was reconstructed in a more cubical form, with a larger quantity of uranium and increased concrete shielding against radiation.

Renamed CP-2, the new reactor began operation in March 1943 and became the focus of important experimental work by Enrico Fermi, Herbert Anderson, Leona Woods Marshall, and other Met Lab scientists who commuted from Hyde Park to Site A on a regular basis. On the University of Chicago campus, the space beneath West Stand of Stagg Field was reconfigured and transformed into a modern laboratory for Met Lab work.