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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.”
J. T. Wajima, H. Yamamoto, H. Kikuchi, T. Ohnishi, S. Kobayashi
Nuclear Science and Engineering | Volume 31 | Number 1 | January 1968 | Pages 19-31
Technical Paper | doi.org/10.13182/NSE68-A18004
Articles are hosted by Taylor and Francis Online.
The microparameters including the thermal-neutron disadvantage factor, DF, the epi- to sub-Cd neutron capture ratio in 238U, ρ28, the epi- to sub-Cd fission ratio in 235U, δ25, and the ratio of the epi-Cd 238U fission to the sub-Cd 235U fission, δ28, were measured in the Ozenji Critical Facility for a seven-rod clustered nuclear superheat fuel element. The factors f, p, and ϵ were derived therefrom and the effect of 235U epithermal fissions on the neutron multiplication factor was observed to be 1.5% Δk/k. Flooding changed the individual factors f, p, and ϵ by amounts corresponding to −6.8% Δk/k, +4.7% Δk/k, and −2.9% Δk/k, respectively, yielding an overall change of −5.1% Δk/k. The maximum discrepancies between measurement and calculation are 1 to 3% for DF, ρ28 , δ25, and δ28; 0.3% Δk/k for f, p, and ϵ; and 0.4% Δk/k for the infinite multiplication factor. The calculation of the effects of flooding on f, p, ϵ, and the infinite multiplication factor agrees with the experiment to within 0.3 to 0.4% Δk/k. When performing the cell calculations, care was taken to determine how to cylinderize the unit cell to perform the one-dimensional calculations with the THERMOS code, how to select the value of the L factor to be used in the JUPITER code (modified MUFT) and how to incorporate the heterogeneous effect of fast fissions.
