The Manhattan Project: Making the Atomic Bomb

Decision on Chemical Extraction

While the Met Lab physicists chafed under DuPont domination, a smoother and quieter relationship existed between the chemists and DuPont. Seaborg and Cooper continued to work well together, and enough progress was made in the semiworks for the lanthanum fluoride process in late 1942 that DuPont moved into the plant design stage and converted the semiworks for the bismuth phosphate method. DuPont pressed for a decision on plutonium extraction methods in late May. Greenewalt chose bismuth phosphate, though even Seaborg admitted he could find little to distinguish between the two. Greenewalt based his decision on the corrosiveness of lanthanum fluoride and on Seaborg's guarantee that he could extract at least fifty percent of the plutonium using bismuth phosphate. DuPont began constructing the chemical separation pilot plant at Oak Ridge, while Seaborg continued refining the bismuth phosphate method.

It was now Cooper's job to design the pile as well as the plutonium extraction facilities at Clinton, both complicated engineering tasks made even more difficult by high levels of radiation produced by the process. Not only did Cooper have to oversee the design and fabrication of parts for yet another new Manhattan Project technology, he had to do so with an eye toward planning the Hanford facility. Safety was a major consideration because of the hazards of working with plutonium, which was highly radioactive. Uranium, a much less active element than plutonium, posed far fewer safety problems.

In July 1942 Compton setup a health division at the Met Lab and put Robert S. Stone in charge. Stone established emission standards and conducted experiments on radiation hazards, providing valuable planning information for the Oak Ridge and Hanford facilities.

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