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P-9 Project
The P-9 Project was the codename given during World War II to the Manhattan Project's heavy water production program. The Cominco plant at Trail, British Columbia, was upgraded to produce heavy water, and three plants were constructed by DuPont in the United States, at the Morgantown Ordnance Works, near Morgantown, West Virginia; at the Wabash River Ordnance Works, near Dana and Newport, Indiana; and at the Alabama Ordnance Works, near Childersburg and Sylacauga, Alabama. The American plants became operational in 1943, and were closed in 1945. The Canadian plant at Trail continued in operation until 1956. Three nuclear reactors were built using the heavy water produced by the P-9 Project: Chicago Pile 3 at Argonne, and ZEEP and NRX at the Chalk River Laboratories in Canada.
==Origins==
Heavy water is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium, also known as heavy hydrogen, rather than the common hydrogen-1 isotope that makes up most of the hydrogen in ordinary water. Deuterium was discovered by Harold Urey in 1931 and he was later able to concentrate it in water. His mentor Gilbert Newton Lewis isolated the first sample of pure heavy water by electrolysis in 1933.
Although a scientific curiosity from the start, considerable interest in heavy water was aroused in 1939 when Hans von Halban and Lew Kowarski suggested that heavy water could be used as a neutron moderator in a nuclear reactor using natural uranium. They had carried out experiments on uranium using ordinary water, but had found that the hydrogen atoms absorbed neutrons, thus preventing the desired chain reaction. The problem with using heavy water was that it was scarce, and scientists could not readily acquire the quantities required by a reactor. At Columbia University in the United States, Enrico Fermi and Leó Szilárd attempted to use graphite as a moderator instead. This turned out to be possible, but the graphite had to be very pure, as impurities, particularly boron, tended to absorb neutrons. On 2 December 1942, Fermi's team initiated the first artificial self-sustaining nuclear chain reaction in an experimental reactor known as Chicago Pile-1.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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