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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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.”
R. C. Lloyd, E. D. Clayton
Nuclear Science and Engineering | Volume 60 | Number 2 | June 1976 | Pages 143-146
Technical Paper | doi.org/10.13182/NSE76-A26870
Articles are hosted by Taylor and Francis Online.
A series of experiments was performed providing new criticality data on plutonium-uranium nitrate solutions in cylindrical and spherical geometry. For the experiments in cylindrical geometry, the plutonium content of the total uranium plus plutonium was ∼30 wt%; whereas, in the case of the water-reflected spheres, measurements were performed with both 15 and 30 wt% plutonium. The uranium in the mixture was slightly depleted, containing 0.66 wt% 235U. The plutonium concentration covered by these experiments ranged between 12.4 to 97.3 g Pu/ℓ (uranium plus plutonium concentrations between 30 to 310 g/ℓ. The 240Pu content of the plutonium was 5.6 wt% in the first case and 4. 7 wt% in the second. The experiments were analyzed using ENDF/B-III cross-section data, and criticality factors were computed in each case. Some comparative calculations also were made, showing the differences obtained with ENDF/B-II, ENDF/B-III, and GAMTEC cross sections. The KENO code, with ENDF/B-III cross sections, as well as the HFN code, provide conservative results on the criticality factors for these systems. The average value of the computed keff for the cylinders, using KENO, was 1.022, and for the spheres, 1.024 using HFN. Thus, using these methods and cross-section data, the computed critical masses and volumes would be expected to be smaller than those measured by ∼2% in terms of keff.