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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.”
K. L. Thomsen
Nuclear Science and Engineering | Volume 119 | Number 3 | March 1995 | Pages 167-174
Technical Paper | doi.org/10.13182/NSE95-A24082
Articles are hosted by Taylor and Francis Online.
The coupled collision probability and interface-current equations in the flat-flux, isotropic approximation are implemented in a light water reactor (LWR) lattice code that is under development. By using traditional Gaussian elimination of the subregion fluxes of the cells, the interface-current equations are turned into a nodal form. In the transformed flux and current equations, expressed in terms of response matrix theory, the coefficients become multiple-flight probabilities, which obey analogous conservation and reciprocity relations as the first-flight probabilities. The convergence of the iterative solution for the interface currents is accelerated by successive overrelaxation (SOR) and global rebalancing techniques. The improvement of the convergence rate is investigated in a series of test calculations. The optimal strategy is found to be alternation between one SOR iteration and three to four free iterations while the rebalancing should be limited to two initial iterations in normal LWR cases.