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ANS Student Conference 2025
April 3–5, 2025
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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.”
M. Segev
Nuclear Science and Engineering | Volume 91 | Number 2 | October 1985 | Pages 143-152
Technical Paper | doi.org/10.13182/NSE85-A27437
Articles are hosted by Taylor and Francis Online.
A deuterium-tritium neutron source is amplified when emitted into a body of material with appreciable (n,2n), (n,3n), and (n,f) cross sections. This amplification is described by a simple theory, approximating the strict integral transport description of the process. The distribution of neutrons in energy, from 14 MeV down to the (n,2n) threshold, is approximated by a generalized slowing down equation, which is similar in form to the infinite medium slowing down equation, and with average collision probabilities taking up the role of scattering fractions. Following a few collisions, the collision source spatial distribution resembles the fundamental mode flux distribution of a critical reactor. The average collision probability for such a source is, in diffusion theory, ∑tr/(∑tr + DB2), where B2 is the geometrical buckling of the system. This yields an expression of the form (αx+βx2)/(l + αx + βx2) for the average collision probability, where x is a representative optical thickness of the system. It has been shown by numerical means that this form for the average collision probability is generally true for centrally peaked sources in variously shaped bare bodies of any optical thickness.