History - Chicago Met Lab

October of 1942 found General Groves in Chicago ready to force a showdown on pile design. Szilard was noisily complaining that decisions had to be made so that design could move to procurement and construction. Compton's delay reflected uncertainty of the superiority of the helium pile and awareness that, engineering studies could not be definitive until the precise value of "k" had been established. Some scientists at the Met Lab urged that a full production pile be built immediately, while others advocated a multi-step process, perhaps beginning with an externally cooled reactor as proposed by Enrico Fermi.

The situation was tailor-made for a man with Groves' temperament. On October 5, 1942, Groves exhorted the Met Lab to decide on final pile design within a week. Even wrong decisions were better than no decisions, Groves claimed, and since time was more valuable than money, more than one approach should be pursued if no single design stood out. While Groves did not mandate a specific decision, his imposed deadline forced the Met Lab scientists to reach a consensus.

As expected, Compton decided on compromise. Fermi would study the fundamentals of pile operation on a small experimental unit to be completed and in operation by the end of the year. Hopefully he would be able to determine the precise value of "k" and make a significant advance in pile engineering. An intermediate pile with external cooling would be built at Argonne and operated until June 1, 1943, when it would be dismantled for plutonium extraction. The helium-cooled Mae West, designed to produce 100 grams of plutonium a day, would be built and operating by March 1944. Studies on liquid-cooled reactors would continue, including Szilard's work with liquid metals.

While the Met Lab labored to make headway on pile design, Glenn Seaborg and his co-workers tried to gain enough information about transuranium chemistry to insure that plutonium produced could be successfully extracted from the irradiated uranium. Using lanthanum fluoride as a carrier, Seaborg isolated a weighable sample of plutonium in August of 1942. At the same time, Isadore Perlman and William J. Knox explored the peroxide method of extraction; John E. Willard studied various materials to determine which best absorbed plutonium; Theodore T. Magel and Daniel K. Koshland researched solvent-extraction processes; and Harrison S. Brown and Orville F. Hill performed experiments into volatility reactions. Basic research on plutonium's chemistry continued as did work on radiation and fission products.

Seaborg's discovery and subsequent isolation of plutonium were major events in the history of chemistry, but, like Fermi's achievement, it remained to be seen whether they could be translated into a production process useful to the bomb effort. In fact, Seaborg's challenge seemed even more daunting, for while "piles" had to be scaled up ten to twenty times, a plutonium separation plant would involve a scale-up of the laboratory experiment on the order of a billion-fold.

Collaboration with DuPont's Charles M. Cooper and his staff on plutonium separation facilities began even before Seaborg succeeded in isolating a sample of plutonium. Seaborg was reluctant to drop any of the approaches then under consideration, and Cooper agreed. The two decided to pursue all four methods of plutonium separation but put first priority on the lanthanum fluoride process Seaborg had already developed. Cooper's staff ran into problems with the lanthanum fluoride method in late 1942, but by then Seaborg had become interested in phosphate carriers. Work led by Stanley G. Thompson found that bismuth phosphate retained over ninety-eight percent plutonium in a precipitate. With bismuth phosphate as a backup for the lanthanum fluoride, Cooper moved forward on a semi-works near Stagg Field at the University of Chicago.

Compton's original plans to build the experimental pile and chemical separation plant on the University of Chicago campus changed during the fall of 1942. The S-1 Executive Committee concurred that it would be safer to put Fermi's pile at Argonne and build the semi-works (pilot plant) and separation facilities at Oak Ridge than to place these experiments in a populous area. On October 3rd, DuPont agreed to design and build the chemical separation plant. Groves tried to entice further DuPont participation at Oak Ridge by having the firm prepare an appraisal of the pile project and by placing three DuPont staff members on the Lewis Committee. Because DuPont was sensitive about its public image (the company was still smarting from charges that it profiteered during World War I), Groves ultimately obtained the services of the giant chemical company for the sum of one dollar over actual costs. In addition, DuPont vowed to stay out of the bomb business after the war and offered all patents to the United States government.

Groves had done well in convincing DuPont to join the Manhattan Project. DuPont's proven administrative structure assured excellent coordination (Crawford Greenwalt was given the responsibility of coordinating all DuPont and Met Lab planning), and Groves and Compton welcomed the company's demand that it be put in full charge of the Oak Ridge plutonium project. DuPont had a strong organization and had studied every aspect of the Met Lab's program thoroughly before accepting the assignment. While deeply involved in the overall war effort, DuPont expected to be able to divert personnel and other resources from explosives work in time to throw its full weight into the Oak Ridge project.

Manhattan Project History

Manhattan Engineer District - The Beginning

Metallurgical Laboratory (Met Lab)

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