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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.”
Karen Dawn Colins
Nuclear Technology | Volume 209 | Number 4 | April 2023 | Pages 582-594
Technical Paper | doi.org/10.1080/00295450.2022.2131953
Articles are hosted by Taylor and Francis Online.
From the published results of experiments investigating the effects of delayed hydride cracking (DHC) on spent fuel Zircaloy cladding integrity, relevant data have been extracted and re-analyzed, taking advantage of inferential statistics and an information-theoretic model selection criterion. Statistical tolerance intervals, the method of maximum likelihood estimation, and the Akaike information criterion, corrected for small sample size, were applied to a small sample of measured values of the threshold stress-intensity factor . The purpose was to create a well-grounded probability density function for use in a mathematical model correlating random variates of with important conditions for the initiation of crack growth by DHC, specifically, cladding hoop stress and the depth and shape of surface flaws. A selection criterion purposely designed for small sample sizes and the robust nature of inferential statistics were ideally suited for the intended reevaluation. The fidelity of the mathematical model was protected by the exclusion of any simplifying approximations, e.g., substitution of constants or single-valued descriptive statistics for variables. The probabilistic effect of the random variable was thereby precisely mapped onto the linearly correlated variable, threshold cladding hoop stress, as a function of surface flaw depth and shape. Contour plots of the results constitute significant improvements over previous quantitative single-point estimates of the effects of DHC on spent fuel Zircaloy cladding integrity.