ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
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!
Latest Magazine Issues
Oct 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
November 2025
Nuclear Technology
Fusion Science and Technology
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.
Charles N. Kelber, Philip Kier
Nuclear Science and Engineering | Volume 8 | Number 1 | July 1960 | Pages 1-11
Technical Paper | doi.org/10.13182/NSE8-1-1
Articles are hosted by Taylor and Francis Online.
Few-group analysis is applied to a variety of D2O-U235 critical assemblies. Use of relatively simple prescriptions for obtaining group constants is sufficient to give good values of the reactivity over a wide range of concentrations of U235 in D2O. Among these simple prescriptions is one which attempts to take into account the spatial variation in the neutron spectrum in reflected systems. Use of this prescription improves the calculated reactivity by about 5% over that obtained with only a single thermal neutron spectrum characteristic of the core.
