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Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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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.”
V. Jagannathan, R. P. Jain, Vinod Kumar, H. C. Gupta, P. D. Krishnani
Nuclear Science and Engineering | Volume 104 | Number 3 | March 1990 | Pages 222-238
Technical Paper | doi.org/10.13182/NSE90-A23722
Articles are hosted by Taylor and Francis Online.
A diffusion iterative scheme has been developed to analyze the basic three-dimensional supercell problem encountered in pressurized heavy water reactors (PHWRs). Multigroup transport calculations are performed essentially in one dimension for the fuel cluster cell and the reactivity device (RD) supercell problems. Iterative diffusion calculations are done in one and two dimensions such that the net transport leakages into the fuel cluster or RD are reproduced. The few-group parameters of the fuel cluster or the boundary conditions on the RD surface are modified for this purpose. With these modifications, the three-dimensional supercell problem is treated by diffusion theory. The accuracy of the new scheme is demonstrated against the corresponding transport solutions in both one and three dimensions. A half-bundle-sized constant mesh is proposed for core diffusion analyses. Since the RDs in a PHWR are rather arbitrarily located, it is difficult to perturb the lattice parameters of controlled meshes properly when a constant mesh size is employed. A flux-related weighting scheme is devised to distribute the δ∑’s in meshes falling within the zone of influence of an RD. This core model is compared with a direct method where the supercell concept is avoided and RDs are simulated by internal boundary conditions directly in the core diffusion simulation. Analysis of certain low-power criticals provides the experimental validation of the calculational schemes.