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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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
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.
R. E. Chrien, H. I. Liou, M. J. Kenny, M. L. Stelts
Nuclear Science and Engineering | Volume 72 | Number 2 | November 1979 | Pages 202-215
Technical Paper | doi.org/10.13182/NSE79-A19464
Articles are hosted by Taylor and Francis Online.
The cross sections for neutron interactions with thorium targets were measured at several energies. Capture cross sections at 0.0253 eV and at 2 and 24.3 keV were measured by activation techniques. Transmission measurements were made from 10 to 100 eV, and capture cross sections were determined from 0.03 to 15 eV by recording discrete lines for the (n,γ) spectrum. The measured thermal cross section is 7.41 ± 0.08 b, at 2 keV the cross section is 1.96 ± 0.10 b, and at 24.3 keV it is 0.540 ± 0.014 b. These values are reported relative to an assumed 231Pa branching ratio of 38.5% for the 311-keV gamma ray, and they do not include the branching ratio error. The results are fitted to R-matrix parameters. The transmission and (n,γ) measurements lead to parameters that give a somewhat higher epithermal capture than previously expected in thorium. This result brings the differential data into better agreement with experiments on subcritical assemblies.