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Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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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.”
Nathan Siu, Ali Mosleh
Nuclear Technology | Volume 84 | Number 3 | March 1989 | Pages 265-281
Technical Paper | Probabilistic Safety Assessment and Risk Management / Nuclear Safety | doi.org/10.13182/NT89-A34210
Articles are hosted by Taylor and Francis Online.
Uncertainties in the estimation of parameters for common-cause failure models arise not only because of the small number of common-cause failure events but also because recorded events may not be relevant to the analysis of a particular plant. The data base for a plant-specific analysis may therefore be uncertain. A Bayesian methodology for treating data base uncertainties in the estimation of common-cause failure model parameters is developed and applied to a three-pump auxiliary feedwater system. Sensitivity analyses show that the results are not strongly sensitive to assumptions concerning prior distribution type and shape, but do depend somewhat on the degree of state-of-knowledge dependence between uncertain events. These analyses also show that ignoring the uncertainties in the data can lead to significant estimation errors. Finally, an approximate methodology for treating uncertain data is examined; this method provides reasonable estimates of the mean values of the common-cause failure model parameters, but underpredicts the uncertainty in these parameters.