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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.
G. E. Hansen
Nuclear Science and Engineering | Volume 8 | Number 6 | December 1960 | Pages 709-719
Technical Paper | doi.org/10.13182/NSE60-3
Articles are hosted by Taylor and Francis Online.
The probability distribution in time at which the neutron population is a slightly supercritical system attains a prescribed level is considered for the case where a source injects well under one neutron per neutron lifetime. For the case of ramp insertion of reactivity it is shown that the energy released in the consequent burst of fissions may in some cases (e.g., unmoderated enriched uranium systems) exceed by over a factor of one hundred the energy release predicted by the reactor kinetics equations.
