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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.
Donald C. Coonfield, Grover Tuck, Harold E. Clark, Bruce B. Ernst
Nuclear Science and Engineering | Volume 39 | Number 3 | March 1970 | Pages 320-328
Technical Paper | doi.org/10.13182/NSE70-A19993
Articles are hosted by Taylor and Francis Online.
Critical masses have been determined by experiment and by calculation for enriched-uranium-metal spherical shells moderated internally with a sphere of mild steel of radius 8.01 cm. The shells were reflected with various thicknesses of mild steel followed by an effectively infinite amount of oil. The points representing critical mass as a function of the thickness of the steel reflector are not related by a smooth curve. The irregularity appears to be most severe for a 3-cm-thick steel reflector and is due to the resonance in the neutron elastic-scattering cross section of iron.
