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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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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.
W. C. Redman, M. M. Bretscher
Nuclear Science and Engineering | Volume 27 | Number 1 | January 1967 | Pages 34-44
Technical Paper | doi.org/10.13182/NSE67-A18040
Articles are hosted by Taylor and Francis Online.
An experimental method for the determination of the spectral average of the capture-to-fission ratio ᾱ for materials inserted in a low-flux reactor is described. The procedure involves a comparison of reactor response to oscillated samples of a fissile material, an absorber, and a spontaneous fission neutron source, plus an experimental determination of fission rate for the fissile material and capture rate for the absorber. In addition, it is necessary that the neutron source be calibrated. These experimental results, combined with a knowledge of the number of neutrons per fission for the fissile material, yield a value of the quantity 1 + ᾱ. This method has been tested in Hi-C Core 10, a critical assembly of 3%-enriched-U02 fuel pins, moderated and reflected by light water, in a lattice spacing which yields a H-to-238U atom ratio of 2:91. The oscillator and absolute counting data yield a value of 0.217 for the central capture-to-fission ratio of 235U, with a standard deviation of ± 0.015. This agrees well with values derived from a combination of measured 235U fission cadmium ratios and calculated thermal and epithermal values for a.
