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Conference Spotlight
2025 ANS Winter Conference & Expo
November 8–12, 2025
Washington, DC|Washington Hilton
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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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Latest News
Japan gets new U for enrichment as global power and fuel plans grow
President Trump is in Japan today, with a visit with new Prime Minister Sanae Takaichi on the agenda. Takaichi, who took office just last week as Japan’s first female prime minister, has already spoken in favor of nuclear energy and of accelerating the restart of Japan’s long-shuttered power reactors, as Reuters and others have reported. Much of the uranium to power those reactors will be enriched at Japan’s lone enrichment facility—part of Japan Nuclear Fuel Ltd.’s Rokkasho fuel complex—which accepted its first delivery of fresh uranium hexafluoride (UF₆) in 11 years earlier this month.
Gerald P. Calame
Nuclear Science and Engineering | Volume 8 | Number 5 | November 1960 | Pages 400-404
Technical Paper | doi.org/10.13182/NSE60-A25820
Articles are hosted by Taylor and Francis Online.
The conventional calculation of power peaking near water gaps assumes an abrupt change in the neutron spectrum at a gap-core interface. The assumption can be seriously in error, and can result in discrepancies of 50% between calculated and experimental peaking values. In this paper, a position-dependent spectrum is obtained by the use of diffusion theory which, when used in peaking calculations, reduces the discrepancy between theory and experiment to the order of 5–10% or less. Recipes based on the position-dependent spectrum are obtained for the specification of position-dependent cross sections which may be used in standard diffusion theory codes. The use of these cross sections in the codes results in an estimate of power peaking factors which represents a considerable improvement over the results given by conventional calculations.
