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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.”
S. R. Bierman, E. D. Clayton, L. E. Hansen
Nuclear Science and Engineering | Volume 50 | Number 2 | February 1973 | Pages 115-126
Technical Paper | doi.org/10.13182/NSE73-2
Articles are hosted by Taylor and Francis Online.
Data are presented from critical experiments with mixed PuO2-UO2 fuels containing 30.0, 14.62, and 7.89 wt% Pu and having H/X (H:Pu + U) atomic ratios of 47.4, 30.6, and 51.8, respectively. In addition to the experimental results, which can be used directly as integral benchmark checkpoints, derived critical sizes are presented for homogeneous mixtures, at theoretical density, of 239PuO2-U(0.71)O2-water in slab, spherical, and cylindrical geometries at the three experimental H/X atomic ratios. These types of data provide the bases for establishing criticality safety control limits.Critical thicknesses of 10.80 ± 0.11, 11.56 ± 0.09, and 14.83 ± 0.60 cm were determined, respectively, for slabs of the 30.0, 14.62, and 7.89 wt% Pu-enriched fuels infinite in two dimensions and fully reflected with 15 cm of Plexiglas. Values of keff within 8 mk of unity were calculated for these three critical systems using either the diffusion theory code, HFN, or the transport theory code, DTF-IV, with the original GAMTEC-II cross-section data previously used at the Critical Mass Laboratory in correlating plutonium critical experiments with theory. Similar calculations with ENDF/B-II cross-section data yielded keff values within 12 mk of unity for these three one-dimensional slab assemblies. Except for the more highly moderated 8 wt% Pu-enriched fuel (H/Pu = 659), calculations with ENDF/B-II data resulted in higher keff values for the critical assemblies than did like calculations using the original GAMTEC-II cross-section library. In the case of the 8 wt% Pu enriched fuel, the computed values for were essentially the same for either of the cross-section sets used.