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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.”
E. E. Lewis, G. Palmiotti
Nuclear Science and Engineering | Volume 130 | Number 2 | October 1998 | Pages 181-193
Technical Paper | doi.org/10.13182/NSE98-A1999
Articles are hosted by Taylor and Francis Online.
Red-black algorithms for solving response matrix equations in one- and two-dimensional diffusion theory are examined. The definition of the partial currents in terms of the scalar flux and net currents is altered to introduce an acceleration parameter that modifies the values of the response matrix elements while leaving the flux and net current solutions unchanged. The acceleration parameter is selected for response matrices derived analytically for slab geometry and from the variational nodal method for both slab and x-y geometries to minimize the spectral radius of the red-black iteration matrix for homogeneous media. The optimal value is shown to be independent of the mesh spacing in the fine mesh limit and to be a function only of c, the scattering-to-total cross section ratio. The method is then generalized to treat multiregion problems by formulating an approximate expression for the optimum acceleration parameter and demonstrated for a series of benchmark diffusion problems.