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Time Periods

1890s-1939:
Atomic Discoveries

1939-1942:
Early
Government Support

1942:
Difficult
Choices

1942-1944:
The Uranium
Path to
the Bomb

1942-1944:
The Plutonium
Path to
the Bomb

1942-1945:
Bringing It All Together

1945:
Dawn of the
Atomic Era

1945-present:
Postscript --
The Nuclear Age


"Met Lab" alumni at the University of Chicago -- Fermi is on the far left of the front row; Zinn is on Fermi's left; Anderson is on the far right of the front row; and Szilard is over Anderson's right shoulder.MORE PILES AND PLUTONIUM
(1942)
Events > Difficult Choices, 1942

At the University of Chicago, meanwhile, Arthur Compton had consolidated most fission research at his new Metallurgical Laboratory(Met Lab).  Compton decided to combine all pile research by stages.  He continued to fund Enrico Fermi's pile research at Columbia University, while Fermi began preparations to move his work to Chicago.  Funding continued as well for the theoretical work of Eugene Wigner at Princeton and of J. Robert Oppenheimer at the University of California, Berkeley.  Compton also appointed Leo Szilard head of materials acquisition and arranged for Glenn T. Seaborg to move his plutonium work from Berkeley to Chicago in April 1942.  

CP-1 construction, November 24, 1942; visible are portions of layers #27, #28, and #29.At the Met Lab, Compton secured materials and space wherever he could find it.  On a racket court under the west grandstand at Stagg Field, Samuel K. Allison began building the graphite and uranium pile that would become CP-1.  Although it was recognized that heavy water would provide a moderator superior to graphite, the only available supply was a small amount that the British had smuggled out of France.  In a decision typical of the new climate of urgency, Compton decided to forge ahead with graphite, a decision made easier by Fermi's increasingly satisfactory results at Columbia and Allison's even better results in Chicago.  In light of recent calculations that cast doubt on the MAUD report's negative assessment of plutonium production, Compton hoped that Allison's pile would provide plutonium that could be used as material for a weapon.  

By May 1942, Bush decided that production planning could wait no longer.  He instructed James Conant to meet with the S-1 section leaders and make recommendations on all approaches to the bomb regardless of cost.  Analyzing the status of the four processes then under consideration for producing fissionable materials for a bomb -- the gaseous diffusion, centrifuge, and electromagnetic uranium isotope separation methods and the plutonium producing pile — the committee decided on May 23 to recommend that all four be pushed as fast as possible to the pilot plant stage and to full production planning.  This decisionS-1 Committee, Bohemian Grove, September 13, 1942. reflected the inability of the committee to distinguish a clear front-runner and its consequent unwillingness to abandon any method.  With the war conceivably hanging in the balance, there was no time either for extended experimentation or for undoing a bad decision.  In the absence of any one clearly best path toward the bomb and with adequate funding and resources, work would proceed on all possible paths simultaneously.

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Sources and notes for this page.

The text for this page was adapted from, and portions were taken directly from the Office of History and Heritage Resources publication: F. G. Gosling, The Manhattan Project: Making the Atomic Bomb (DOE/MA-0001; Washington: History Division, Department of Energy, January 1999), 10-11.  The terms "atomic pile" and "nuclear reactor" refer to the same thing.  The term "pile" was more common during early atomic research, and it was gradually replaced by "reactor" in the later years of the Manhattan Project and afterwards.  In this web site, the phrase "pile (reactor)" is used to refer to early, experimental piles, and "reactor (pile)" is used to refer to later production reactors, which had more elaborate controls and in general more closely resembled post-war reactors.  Much as the term "pile" gradually gave way to "reactor," "atomic" was gradually replaced by "nuclear."  Click here for more information on the photograph of "Met Lab Alumni."  The photograph of the construction of CP-1 is courtesy the Argonne National Laboratory; it is reprinted in Rachel Fermi and Esther Samra, Picturing the Bomb: Photographs from the Secret World of the Manhattan Project (New York: Harry N. Abrams, Inc., Publishers, 1995), 103.  Click here for more information on the photograph of the S-1 (Uranium) Committee.

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