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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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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.
M. M. R. Williams
Nuclear Science and Engineering | Volume 19 | Number 2 | June 1964 | Pages 221-229
Technical Paper | doi.org/10.13182/NSE64-A28913
Articles are hosted by Taylor and Francis Online.
By associating the absorption cross section with the Laplace transform variable in the time domain, it is shown how Corngold's asymptotic solution for slowing down can be applied directly to the problem of a pulse of neutrons slowing down in an infinite medium. In this way, the effect of chemical binding and thermal motion on the slowing-down time, dispersion and spectrum shape have been determined. Some new results for these quantities have been obtained, and the limitations of the asymptotic method have been pointed out. A first-order correction to the slowing-down time has been deduced for a finite medium large enough to be characterized by a DB2 term.
