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Division Spotlight
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.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
Standards Program
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.”
Tsuyoshi Misawa, Seiji Shiroya, Keiji Kanda
Nuclear Technology | Volume 83 | Number 2 | November 1988 | Pages 162-170
Technical Paper | Fission Reactor | doi.org/10.13182/NT88-A34157
Articles are hosted by Taylor and Francis Online.
A criticality safety study on a light water moderated and reflected coupled core loaded with highly enriched uranium fuel was performed in the Kyoto University Critical Assembly. The critical mass and neutron flux distribution were measured systematically as a function of the separation distance between the two cores, varying the H/235U atomic ratio (i.e., the moderator-to-fuel volume ratio). These data were analyzed with the SRAC code system to assess the capability of diffusion theory to analyze the coupled-core system. It was found that the critical mass of the coupled core showed the minimum when the two cores were separated by a certain distance depending on the neutron spectrum in the core region. The neutron flux peak value at the water gap region reached the maximum when the separation distance was 5 to 6 cm. The results calculated with the diffusion code installed in the SRAC system agreed well with the experimental data.
