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Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
G. Kistner and J. T. Mihalczo
Nuclear Science and Engineering | Volume 35 | Number 1 | January 1969 | Pages 27-44
Technical Paper | doi.org/10.13182/NSE69-A21112
Articles are hosted by Taylor and Francis Online.
A series of static critical experiments has been performed on an accurate mockup of the SORA Reactor. SORA is a proposed NaK cooled, repetitively pulsed fast reactor which would be used as a high-intensity neutron source for time-of-flight experiments. The reactivity of this reactor is varied by a movable reflector. Those parameters which are related to the kinetics of the reactor have been investigated thoroughly in the critical experiments. They have been measured for both beryllium and iron reflectors of several sizes and for various core and fixed reflector configurations. The total reactivity of the movable reflectors varied from $3.7 for a 11.0-cm-wide iron reflector to $12 for a 26.2-cm-wide beryllium reflector. The reactivity of the movable reflector as a function of its position has been shown to have a parabolic dependence on position characterized by the parameter αx, which varied from 4 to 9.9¢/cm2. The prompt-neutron time decay is described by a fast decay constant which varied between 0.30 and 0.55/µ sec and a slow decay constant which varied between 0.05 and 0.10/µ sec. The critical mass for the various experiments was between 50.3 and 57.3 kg of uranium enriched to 93.2 wt% 235U. Using space-independent neutron kinetics with one delayed-neutron group, it has been shown that with a 24-cm-high × 7-cm-thick × 21-cm-wide beryllium reflector the assembly will produce 100 pulses/sec ∼50-µsec wide at half-maximum power with a peak-to-average power ratio of ∼180.