This table summarizes the chronology of the Hanford project, the plant that produced the plutonium for the first nuclear bomb. In April, 1942, Eugene Wigner arrived in Chicago and set out to design this plant. At the time, no one had even demonstrated that a chain reaction was possible. Little was known about nuclear cross sections or just about anything else. Wigner, on instinct, decided to use water as the coolant. He went straight to 250 MWt when no zero MWt plant existed. In five months, his five man team using adding machines and slide rules completed the design.

Only toward the end of that period was the first chain reaction demonstrated using a pile of graphite blocks in a squash court. In February 1943, Wigner convinced the Army to go with his water cooled plant and then scaled the design up another factor of two. About the same time Hanford, WA was chosen as the location, the locals evicted, and in August of 1943 construction started. A year later the plant went critical and in October, 1944 started producing plutonium. In 2.5 years, Wigner went from literally zero to 500 MWt. Wigner was furious that it took this long, blaming “too much money”.