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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. D. M. Garcia
Nuclear Science and Engineering | Volume 177 | Number 1 | May 2014 | Pages 35-51
Technical Paper | doi.org/10.13182/NSE13-45
Articles are hosted by Taylor and Francis Online.
The analytical discrete ordinates (ADO) method is used to develop an approximate, but accurate, solution to a one-dimensional model of neutral particle transport in ducts proposed originally by Prinja and Pomraning. The implementation of the ADO method is facilitated by a variable transformation that is used to rewrite the Prinja-Pomraning equation in a form very similar to that of the Bhatnagar-Gross-Krook model equation in rarefied gas dynamics. Techniques of linear algebra are used to find an analytical solution for the linear system that has to be solved for the superposition coefficients of the ADO method in the case of a semi-infinite duct. Numerical results for the reflection and transmission probabilities that illustrate the capability of the method are tabulated for semi-infinite and finite ducts of circular cross section and two types of particle incidence: isotropic incidence and incidence described by the Dirac delta distribution. It is concluded that the ADO method can achieve a desired precision in the reflection and transmission probabilities with a much lower quadrature order than previously used numerical implementations of the discrete ordinates method and consequently is much more efficient.
