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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.”
S. N. Purohit
Nuclear Science and Engineering | Volume 9 | Number 3 | March 1961 | Pages 305-313
Technical Paper | doi.org/10.13182/NSE61-A25881
Articles are hosted by Taylor and Francis Online.
The time-dependent energy spectra, for times greater than the slowing-down time, were generated in a monatomic heavy gas with the help of a multigroup formalism. These spectra were obtained for the infinite as well as finite media of beryllium and graphite. The behavior of asymptotic energy spectra during the last stage of neutron thermalization and diffusion periods was studied. The thermalization time constant for the establishment of the final Maxwellian velocity distribution of neutrons, in a monatomic heavy gas, was estimated to be equal to (1.176ξΣs0υ0)−1. Total thermalization times for neutrons in beryllium and graphite were found to be equal to 114 and 238 µsec, respectively. Using the energy-dependent transport mean free path, the diffusion cooling coefficient for beryllium was calculated to be equal to 0.890 cm2 For graphite, under the constant diffusion coefficient assumption, the diffusion cooling coefficient was determined to be equal to 1.922 cm2.
