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The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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.”
Rodolfo M. Ferrer, Joel D. Rhodes III
Nuclear Science and Engineering | Volume 182 | Number 2 | February 2016 | Pages 151-165
Technical Paper | doi.org/10.13182/NSE15-6
Articles are hosted by Taylor and Francis Online.
A linear source (LS) approximation scheme is presented for the two-dimensional method of characteristics (MOC). The LS approximation relies on the computation of track-based spatial moments over source regions to obtain the LS expansion coefficients. The proposed LS scheme improves the solution accuracy relative to the constant or flat source (FS) approximation. The LS scheme is capable of treating arbitrarily shaped source regions under isotopic or anisotropic scattering assumptions. The LS scheme is also compatible with standard coarse-mesh finite difference acceleration. Numerical tests presented for the C5G7 mixed oxide benchmark show that for comparable accuracy with respect to the reference solution, the LS approximation can reduce the run time by a factor of 4 and the memory requirements by a factor of 10 relative to the FS scheme. This is because the LS scheme permits the use of a much coarser grid than the FS scheme. Numerical tests presented for simple cold critical core configurations with anisotropic scattering confirm the advantage of using the LS scheme.
