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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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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.
S. A. Hasnain, D. Okrent
Nuclear Science and Engineering | Volume 9 | Number 3 | March 1961 | Pages 314-322
Technical Paper | doi.org/10.13182/NSE61-A25882
Articles are hosted by Taylor and Francis Online.
The performance of some blanket designs is studied using economically optimized cycling based on a simple economics model. For an 800-liter core fast reactor having a 45-cm radial blanket and an average core power of 1-Mw per liter, it appears that the outermost blanket elements make enough plutonium to pay for the cost of their fabrication and processing, unless the core power density falls well below the expected value. A cyclic motion of elements in the inward radial direction has little effect on the economics if optimum cycling is followed. Moving the blanket elements may have engineering advantages however, such as a uniform buildup and burnup, and less variation in power locally with time. A paste blanket with radial inward motion and axial mixing has a similar behavior. Inclusion of moderating material in a fast reactor blanket is not promising for a high-power density reactor using optimum cycling, but it may prove valuable if blanket fluxes get very low or the residence times of the blanket elements are limited.