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Conference Spotlight
2025 ANS Winter Conference & Expo
November 8–12, 2025
Washington, DC|Washington Hilton
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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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.
C. B. Mills
Nuclear Science and Engineering | Volume 13 | Number 4 | August 1962 | Pages 301-305
Technical Paper | doi.org/10.13182/NSE62-A26172
Articles are hosted by Taylor and Francis Online.
The complete spatial separation of moderator and uranium fuel bearing regions are shown by experiment to result in critical reactors with low critical mass and relatively uniform fissioning density. Studies of several of these experiments to establish the accuracy of a numerical method of calculation (SNG) for this class of problems show good correspondence between theory and experiment. This method is then used for a useful survey of critical mass and U235 atomic density as a function of geometry for the best moderators, D2O and Be.
