page_title: Metallurgical Laboratory
section_title: Chicago Pile-3
hierarchical_section_title: Metallurgical Laboratory / Reactor development / Chicago Pile-3
caption_attribution_description: Courtesy &lt;a href="http://www.anl.gov/" rel="nofollow"&gt;Argonne National Laboratory.&lt;/a&gt; Neg. No. 1-40
context_page_description: The Metallurgical Laboratory was a scientific laboratory at the University of Chicago that was established in February 1942 to study and use the newly discovered chemical element plutonium. It researched plutonium's chemistry and metallurgy, designed the world's first nuclear reactors to produce it, and developed chemical processes to separate it from other elements. In August 1942 the lab's chemical section was the first to chemically separate a weighable sample of plutonium, and on 2 December 1942, the Met Lab produced the first controlled nuclear chain reaction, in the reactor Chicago Pile-1, which was constructed under the stands of the university's old football stadium, Stagg Field.
  The Metallurgical Laboratory was established as part of the Metallurgical Project, also known as the "Pile" or "X-10" Project, headed by Chicago professor Arthur H. Compton, a Nobel Prize laureate. In turn, this was part of the Manhattan Project – the Allied effort to develop the atomic bomb during World War II. The Metallurgical Laboratory was successively led by Richard L. Doan, Samuel K. Allison, Joyce C. Stearns and Farrington Daniels.
context_section_description: A second reactor, known as Chicago Pile-3, or CP-3, was built at the Argonne site in early 1944. This was the world's first reactor to use heavy water as a neutron moderator. It had been unavailable when CP-1 was built, but was now becoming available in quantity thanks to the Manhattan Project's P-9 Project. The reactor was a large aluminum tank, 6 feet (1.8 m) in diameter, which was filled with heavy water, which weighed about 6.5 short tons (5.9 t). The cover was pierced by regularly spaced holes through which 121 uranium rods sheathed in aluminum projected into the heavy water. The tank was surrounded by a graphite neutron reflector, which in turn was surrounded by a lead shield, and by concrete. Shielding on the top of the reactor consisted of layers of 1-foot (30 cm) square removable bricks composed of layers of iron and masonite. The heavy water was cooled with a water-cooled heat exchanger. As well as the control rods, there was an emergency mechanism for dumping the heavy water into a tank below. Construction began on 1 January 1944. The reactor went critical in May 1944, and was first operated at full power of 300 kW in July 1944.
  During the war Zinn allowed it to be run around the clock, and its design made it easy to conduct experiments. This included tests to investigate the properties of isotopes such as tritium and determine the neutron capture cross section of elements and compounds that might be used to construct future reactors, or occur in impurities. They were also used for trials of instrumentation, and in experiments to determine thermal stability of materials, and to train operators.
caption: Chicago Pile-3
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