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ANS Student Conference 2025
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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.”
Jeremy Lloyd Conlin, James Paul Holloway
Nuclear Science and Engineering | Volume 169 | Number 2 | October 2011 | Pages 168-177
Technical Paper | doi.org/10.13182/NSE10-72
Articles are hosted by Taylor and Francis Online.
This paper introduces the explicitly restarted Arnoldi's method for calculating eigenvalues and eigenvectors in a Monte Carlo criticality calculation. Arnoldi's method is described along with the power method. The power method has been used for decades for Monte Carlo criticality calculations despite the availability of other algorithms with better convergence properties. The Monte Carlo application of the transport-fission operator of the Boltzmann transport equation is defined, and the Monte Carlo implementation of both Arnoldi's method and the power method are described. A brief discussion of eigenvalue and fission source convergence is given. Numerical simulations of one-demensional slab geometries are presented, demonstrating the convergence of both the eigenvalue and fission source (as measured by the Shannon entropy) for both Arnoldi's method and the power method. The results show that Arnoldi's method does not need to discard iterations like the power method because both the eigenvalue and fission source appear to converge immediately, even for problems with high dominance ratios.
