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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.”
Toshihiro Yamamoto, Yoshinori Miyoshi, Takehide Kiyosumi
Nuclear Science and Engineering | Volume 145 | Number 1 | September 2003 | Pages 132-144
Technical Paper | doi.org/10.13182/NSE03-A2369
Articles are hosted by Taylor and Francis Online.
Evaluated criticality benchmark data obtained at the Static Criticality Experiment Facility (STACY) account for a large percentage of low-enriched uranium (LEU) solution systems documented in the "International Handbook of Evaluated Criticality Safety Benchmark Experiments." These data are available for validation of computer codes and nuclear data used for criticality safety analyses of LEU solution systems. The calculated keff's for the water-reflected STACY criticality experiments have been overestimated with JENDL-3.2 by ~0.7%. These overestimations were kept in mind while making modifications of the fission spectrum and the fission cross section of 235U, and the (n,p) cross section of 14N in JENDL-3.3. Because of these modifications, the keff's calculated with JENDL-3.3 were largely improved. The contributions of these modifications in JENDL-3.3 with respect to JENDL-3.2 and ENDF/B-VI.5 were investigated by performing perturbation calculations. The overestimation of the elastic-scattering cross section of 56Fe in the mega-electron-volt range was one of the reasons for the keff overestimations for the STACY experiments with JENDL-3.2. The modification of 56Fe cross sections in JENDL-3.3 reduces keff's in the STACY experiments by 0.2%. The dependence of calculated keff's on uranium concentration still exists in JENDL-3.3. The overestimation of calculated keff's for the STACY experiments with JENDL-3.3 is not insignificant and is as much as 0.6%. These problems are to be resolved in a future evaluation of the cross-section library.