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Division Spotlight
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
DOE extends Centrus’s HALEU production contract by one year
Centrus Energy has announced that it has secured a contract extension from the Department of Energy to continue—for one year—its ongoing high-assay low-enriched uranium (HALEU) production at the American Centrifuge Plant in Piketon, Ohio, at an annual rate of 900 kilograms of HALEU UF6. According to Centrus, the extension is valued at about $110 million through June 30, 2026.
Hisashi Hishida, Tamotsu Sekiya
Nuclear Science and Engineering | Volume 47 | Number 3 | March 1972 | Pages 319-328
Technical Paper | doi.org/10.13182/NSE72-A22418
Articles are hosted by Taylor and Francis Online.
A heterogeneous method of calculating time-dependent reactor core characteristics, such as the time variation in thermal-neutron flux distribution and the reactivity change during fuel and poison burnup, is derived. The lattice consists of an infinite number of similar square zones closely connected to one another. In each zone, identical fuel rods are arranged in a regular lattice with a burnable poison rod of the same geometric dimensions as a fuel rod at the center. Some numerical examples, utilizing the equations derived finally, give the time variation in poison concentration and k∞(t) for a zone showing the heterogeneity effect associated with a burnable poison rod. Since the machine time required to compute the time variation of such core characteristics through fuel life of 11,000 EFPH as shown in the examples is <25 sec on the IBM 360/75 per case, the method may be applied to the preliminary survey calculation for the time-dependent heterogeneous core characteristics of a square lattice including burnable poison rods as well as to more general time-dependent problems related to such lattices.