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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.”
Ding She, Ang Zhu, Kan Wang
Nuclear Science and Engineering | Volume 175 | Number 3 | November 2013 | Pages 259-265
Technical Paper | doi.org/10.13182/NSE12-48
Articles are hosted by Taylor and Francis Online.
Burnup calculations consider the time dependence of the material composition or isotope inventory, which has important influence on the neutronic properties of a nuclear reactor. An essential part of burnup calculations is to solve the burnup equations, which can be approximately treated as a first-order linear system and can be solved by means of matrix exponential methods. However, because of the large decay constants of short-lived nuclides, the coefficient matrix of the burnup equations has a large norm and a vast range of spectra. Consequently, it is quite difficult to directly compute the matrix exponential using conventional methods such as the truncated Taylor expansion and the Pade approximation. Recently, the Chebyshev rational approximation method (CRAM), which is based on rational functions on the complex plane, has shown the capability to deal with this problem. In this paper an alternative method based on the generalized Laguerre polynomials is proposed to compute the exponential of the burnup matrix. Against CRAM, the Laguerre polynomial approximation method (LPAM) has simple recursions for obtaining the coefficients in any order, and all the computations are real arithmetic. A point burnup case and a pin-cell burnup case are calculated for validation, and results show that LPAM is promising for burnup calculations.