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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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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.”
H. S. Kim, S. I. Abdel-Khalik
Nuclear Technology | Volume 69 | Number 3 | June 1985 | Pages 268-278
Technical Paper | Nuclear Safety | doi.org/10.13182/NT85-A33610
Articles are hosted by Taylor and Francis Online.
Natural convection heat transfer in simulated core debris beds has been examined. The debris beds are simulated using electrically heated packed tube bundles arranged in either a square or staggered lattice with porosities varying between 0.31 and 0.95. The effects of bed height, heat generation rate, particle size, porosity, overlying liquid layer height, and top surface boundary condition on the downward and upward power fractions and Nusselt numbers have been determined. Flow patterns within the bed and overlying fluid region have been visualized using particle tracing techniques. Correlations for the downward and upward Nusselt numbers, NuB and NuT, as functions of the internal Rayleigh number have been developed. In all cases, the beds are bounded from below by a cooled isothermal surface. When the overlying fluid is bounded from above by a cooled solid isothermal surface, the Nusselt numbers are given by NuB = 0.424 Ra0.226 and NuT = 1.61 Ra0.220. When the upper surface of the overlying fluid is free, the downward Nusselt number is given by NuB = 0.503 Ra0.180. These correlations are valid for the ranges 102 ≤ Ra ≤ 107 and 0.1 ≤ η ≤1.0, where η is the ratio between the heights of the overlying fluid layer and the bed.