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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.”
Young-Sik Cho, Young-Ouk Lee
Nuclear Science and Engineering | Volume 177 | Number 1 | May 2014 | Pages 90-96
Technical Paper | doi.org/10.13182/NSE12-96
Articles are hosted by Taylor and Francis Online.
Recent evaluations of neutron cross-section covariances in the resolved resonance region reveal the need for further research in this area. Major issues include declining uncertainties in multigroup representations and the proper treatment of scattering radius uncertainty. To address these issues, the present work develops a formalism and computer code based on a multilevel Breit-Wigner formula, extending the previous work based on the kernel approximation, using resonance parameter uncertainties from the Atlas of Neutron Resonances. Analytical expressions derived for average cross-section uncertainties in the arbitrary energy bin along with their sensitivities provide a fundamental tool for determining the cross-section uncertainties. The role of resonance-resonance and resonance-potential scattering correlations is studied. As a test case, we apply this approach to estimate (n,γ) and (n,el) covariances for the structural material 55Mn and compare the results with those from the previous kernel approximation.
