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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.
E. A. Mason, J. A. Larrimore
Nuclear Science and Engineering | Volume 9 | Number 3 | March 1961 | Pages 332-340
Technical Paper | doi.org/10.13182/NSE61-A25884
Articles are hosted by Taylor and Francis Online.
In reactors fueled with thorium, increasing specific power leads to reduction of fuel reactivity lifetime and conversion ratio because of the appreciable decay time and neutron absorption cross section of Pa233. A generalized study of these effects in thorium-U233 fueled reactors has been carried out using a simplified reactor model. It was found that the most important specific power effect on fuel reactivity is the holdup of Pa233, rather than its burnout to U234. Using conventional cost bases, the effect of specific power on the fuel costs for thorium fueled reactors has been shown to be small in the range of practical specific powers.
