The Ames Project was a research and development project that was part of the larger Manhattan Project to build the first atomic bombs during World War II. It was founded by Frank Spedding from Iowa State College in Ames, Iowa as an offshoot of the Metallurgical Laboratory at the University of Chicago devoted to chemistry and metallurgy, but became a separate project in its own right. The Ames Project developed the Ames Process, a method for preparing pure uranium metal that the Manhattan Project needed for its atomic bombs and nuclear reactors. Between 1942 and 1945, it produced over of uranium metal. It also developed methods of preparing and casting thorium, cerium and beryllium. In October 1945 Iowa State College received the Army-Navy "E" Award for Excellence in Production, an award usually only given to industrial organizations. In 1947 it became the Ames Laboratory, a national laboratory under the Atomic Energy Commission.
Background The discovery of the neutron by James Chadwick in 1932, followed by that of nuclear fission by German chemists Otto Hahn and Fritz Strassmann in 1938, and its theoretical explanation (and naming) by Lise Meitner and Otto Frisch soon after, opened up the possibility of a controlled nuclear chain reaction with uranium. On 20 December 1941, soon after the Japanese attack on Pearl Harbor that brought the United States into World War II, the Nobel Prize-winning physicist Arthur H. Compton was placed in charge of the plutonium project, the objective of which was to produce reactors to convert uranium into plutonium, to find ways to chemically separate plutonium from the uranium, and ultimately to design and build an atomic bomb. This became the Manhattan Project. Although a successful reactor had not yet been built, the scientists had already produced several different but promising design concepts.
Compton established the project's Metallurgical Laboratory at the University of Chicago in February 1942. Its mission was to build nuclear reactors to create plutonium that would be used in atomic bombs. For advice on assembling the laboratory's Chemistry Division, Compton, a physicist, turned to Herbert McCoy, who had considerable experience with isotopes and radioactive elements. McCoy recommended Frank Spedding from Iowa State College in Ames, Iowa, as an expert on the rare-earth elements, which were chemically similar to the actinide series that included uranium and plutonium. Compton asked Spedding to become the head of the Metallurgical Laboratory's Chemistry Division.
Owing to a lack of space at the University of Chicago, Spedding proposed to organize part of the Chemistry Division at Iowa State College, where he had colleagues who were willing to help. It was agreed that Spedding would spend half of each week in Ames, and half in Chicago. The intention was that staff at Ames would eventually move to Chicago when space became available, but this never happened. The success of the Ames Project ensured that it became a separate laboratory within the Manhattan Project.
Organization Spedding started by recruiting two fellow scientists at Iowa State College to become his associate directors; Harley A. Wilhelm, an expert in spectrochemistry and metallurgy, as the head of the Ames Project's Metallurgy Division, and Iral B. Johns as the head of the Plutonium Division. Under them were eight section chiefs. The Ames Project grew to over 90 scientific staff. The total number of staff eventually exceeded 500. Senior staff would meet on Sunday mornings to review the previous week's work and set goals for the week ahead, a process that came to be called "Speddinars". At first Spedding had to depart for Chicago soon after each meeting, but in early 1943 he was succeeded as head of the chemistry division at the Metallurgical Laboratory by James Franck, allowing Spedding to spend more time at Ames. He remained an associate director at the Metallurgical Laboratory.
Spedding was fortunate in having the full support of Charles E. Friley, the president of Iowa State College, even though the nature of the work could not at first be disclosed to him while security checks were being undertaken. Once these were completed, Friley brought in Harold V. Gaskill, the dean of science, as the Ames Project's administrator. The United States Army Corps of Engineers took control of the Manhattan Project in June 1942, and the Ames Project in late 1942.
Uranium Ames Process The first item on the agenda was to find uranium for the nuclear reactor that Enrico Fermi was proposing to build. Uranium ore was readily available. Some of high-grade ore from the Belgian Congo was in storage in a warehouse at Port Richmond on Staten Island. About per annum was being mined at the Eldorado Mine at Port Radium on the Great Bear Lake near the Arctic Circle in Canada's Northwest Territories. The Eldorado company also operated a refinery at Port Hope, Ontario, where Canadian and Belgian ore was refined. The Manhattan Project's estimated requirements for 1942 were , of which Compton required just for his proposed nuclear reactor.
The major problem was impurities in the uranium oxide, which could act as neutron poisons and prevent a nuclear chain reaction. Due to the presence of impurities, references published before 1942 typically listed its melting point at around when pure uranium metal actually melts at . Peter P. Alexander, at Metal Hydrides Incorporated, gave in 1938 the first indications that the melting point of uranium was "as low as and even somewhat lower".
The most effective way to purify uranium oxide in a laboratory was to take advantage of the fact that uranium nitrate is soluble in ether. Scaling this process up for industrial production was a dangerous proposition; ether was explosive, and a factory using large quantities was likely to blow up or burn down. Compton and Spedding turned to Mallinckrodt in St. Louis, Missouri, which had experience with ether. Spedding went over the details with Mallinckrodt's chemical engineers, Henry V. Farr and John R. Ruhoff, on 17 April 1942. Within a few months, sixty tons of highly pure uranium oxide was produced.
The only uranium metal available commercially was produced by the Westinghouse Electric and Manufacturing Company, using a photochemical process. Uranium oxide was reacted with potassium fluoride in large vats on the roof of Westinghouse's plant in Bloomfield, New Jersey. This produced ingots the size of a quarter that were sold for around $20 per gram. But Edward Creutz, the head of the Metallurgical Laboratory's group responsible for fabricating the uranium, wanted a metal sphere the size of an orange for his experiments. With Westinghouse's process, it would have cost $200,000 and taken a year to produce. The hydride or "hydramet" process, developed by Alexander used calcium hydride as the reducing agent for the conversion of uranium ore to metal. By this means the Metal Hydrides plant in Beverly, Massachusetts, managed to produce a few pounds of uranium metal. Unfortunately, the calcium hydride contained unacceptable amounts of boron, a neutron poison, making the metal unsuitable for use in a reactor. Some months would pass before Clement J. Rodden from the National Bureau of Standards and Union Carbide figured out a means to produce sufficiently pure calcium hydride.
Spedding and Wilhelm began looking for ways to create the uranium metal. At the time, it was produced in the form of a powder, and was highly pyrophoric. It could be pressed and sintered and stored in cans, but to be useful, it needed to be melted and cast. Casting presented difficulty because uranium corroded crucibles of beryllium, magnesia and graphite. To produce uranium metal, they tried reducing uranium oxide with hydrogen, but this did not work. While most of the neighboring elements on the periodic table can be reduced to form pure metal and slag, uranium did not behave this way. In June 1942 they then tried reducing the uranium with carbon in a hydrogen atmosphere, with only moderate success. They then tried aluminum, magnesium and calcium, all of which were unsuccessful. The following month the Ames team found that molten uranium could be cast in a graphite container. Although graphite was known to react with uranium, this could be managed because the carbide formed only where the two touched.
Around this time, someone from the Manhattan Project's Berkeley Radiation Laboratory brought a cube of uranium tetrafluoride—the uranium compound being used in the calutrons—to the Metallurgical Laboratory to discuss the possibility of using it rather than uranium oxide in the reactor. Spedding began wondering whether it would be possible to produce uranium metal from this salt, bypassing the problems with oxygen. He took the cube back to Ames, and asked Wilhelm to investigate. The task was assigned to an associate, Wayne H. Keller. He investigated a process (now known as the Ames process) originally developed by J. C. Goggins and others at the University of New Hampshire in 1926. This involved mixing uranium tetrachloride (from which Eugène-Melchior Péligot first prepared pure uranium by reduction with potassium in 1841:fr:s:Page:Comptes rendus hebdomadaires des séances de l’Académie des sciences, tome 013, 1841.djvu/429) and calcium metal in a calcium oxide-lined steel pressure vessel (known as a "bomb") and heating it. Keller was able to reproduce Goggin's results on 3 August 1942, creating a button of very pure uranium metal. The process was then scaled up. By September, bombs were being prepared in steel pipes long, lined with lime to prevent corrosion, and containing up to of uranium tetrafluoride. C. F. Gray took these ingots and cast them into a billet of pure uranium.
Production On 24 September 1942, Wilhelm took the ingot to Spedding at the Metallurgical Laboratory in Chicago and presented it to Compton, whose first reaction was of disbelief. He thought it must be hollow. Spedding had the ingot cut open. It was not hollow. A few days later, the Metallurgical Laboratory's director, Richard L. Doan, went to Ames, where he drew up an Office of Scientific Research and Development (OSRD) contract for the Ames Project to produce of pure uranium metal a day. This would be a pilot plant, with the process eventually being transferred to industry. The OSRD contract was superseded by a Manhattan Project contract in November 1942. The initial contract was for $50,000. By 31 December 1945, the face value of contracts let to the Ames Project totaled $6.907 million; but the work was carried out for $4 million.
Wilhelm found an old wooden building on the southeastern edge of the campus. It had been a home economics building until 1926, and then had served as a women's gymnasium until a new one was built in 1941; by 1942 it was mainly used for storage. The building was handed over to the Ames Project, and the wooden floor replaced with a concrete one, much to the disappointment of the university architect, who had been trying for some years to get the place torn down. The building officially became known as the Physical Chemistry Annex; local people called it "Little Ankeny", after the nearby town of Ankeny, Iowa, where there was an ordnance plant. Looking for machine tools, Wilhelm found a machine shop for sale in Ames. The owner, Bill Maitland, had once made gardening tools, but could no longer obtain the metal he needed due to wartime rationing. Wilhelm bought it for $8,000. The Metallurgical Laboratory supplied two large 40-kilowatt reduction furnaces.