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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.”
C. Vaglio-Gaudard, A. Santamarina, D. Bernard, G. Noguère, J. M. Ruggieri, J. F. Vidal, A. Lyoussi
Nuclear Science and Engineering | Volume 166 | Number 3 | November 2010 | Pages 267-275
Technical Paper | doi.org/10.13182/NSE09-103
Articles are hosted by Taylor and Francis Online.
The 56Fe international covariance matrices recommend variances for capture, elastic, and inelastic cross sections. Analysis shows that these matrices are often inconsistent and unrealistic. A new covariance matrix was established on the basis of feedback from the interpretation of two integral benchmarks representative of Generation III and Generation IV reflectors. Flux attenuation in the reflector at various energies demonstrates good agreement between calculation and experiment. The RDN code based on a nonlinear regression method using an iterative technique (limited to the first Gauss-Newton iteration in this study) was used to reestimate 56Fe cross sections and to deduce the a posteriori covariance matrix associated with the JEFF3.1.1 library. The results highlight that the 56Fe cross-section levels in the JEFF3.1.1 library are satisfactory. The new covariance matrix can then be used as a reference to calculate uncertainty propagation.
