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The mission of the Decommissioning and Environmental Sciences (DES) Division is to promote the development and use of those skills and technologies associated with the use of nuclear energy and the optimal management and stewardship of the environment, sustainable development, decommissioning, remediation, reutilization, and long-term surveillance and maintenance of nuclear-related installations, and sites. The target audience for this effort is the membership of the Division, the Society, and the public at large.
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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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.
U. Hansen, E. Teuchert
Nuclear Science and Engineering | Volume 44 | Number 1 | April 1971 | Pages 12-17
Technical Paper | doi.org/10.13182/NSE44-12
Articles are hosted by Taylor and Francis Online.
The heterogeneity due to lumping the fuel in coated particles affects the thermal-neutron spectrum. A calculational model is discussed which, apart from some simplifying assumptions about the statistical distribution, allows a rigorous computation of effective cross sections for all nuclides of the heterogeneous medium. It is based on an exact computation of the neutron-penetration probability through coating and kernel. The model is incorporated in a THERMOS code providing a double heterogeneous cell calculation that can be repeated automatically at different time steps in the depletion code system MAFIA-V.S.O.P. A discussion of the effects of the coated-particle structure is given by a comparison of calculations for heterogeneous and homogeneous fuel zones in pebble bed reactor elements. This is performed for enriched UO2 fuel and for a ThO2-PuO2 mixture in the grains. Depending on the energy-dependent total sigmas in the kernels, the changes of the cross sections range from 0.1 up to 45%. The influence on the spectrum-averaged sigmas of the nuclides in the fresh UO2 fuel is lower than 1%. For the emerging 240Pu it increases up to 3.3% during irradiation. For the ThO2-PuO2 fuel, the averaged sigmas of the isotopes vary from 0.5 to 5.7% depending on the state of irradiation. Correspondingly, there is an influence on the plutonium isotopic composition, on breeding ratios, and on the tilt of keff during burnup which will be discussed in detail.
