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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.
Paul J. Turinsky, James J. Duderstadt
Nuclear Science and Engineering | Volume 45 | Number 2 | August 1971 | Pages 167-181
Technical Paper | doi.org/10.13182/NSE71-A20883
Articles are hosted by Taylor and Francis Online.
Several applications of the degenerate kernel technique (DKT) for treating the speed dependence in steady-state neutron thermalization calculations are studied both analytically and computationally. An iterative improvement technique is developed for fine thermal spectrum calculations. It is shown that the size of the degenerate kernel expansion (DKE) required to obtain consistent accuracy with a given number of discrete speed mesh points can be decoupled from the speed mesh structure by such a technique. This decoupling allows a more efficient numerical solution and hence a savings in computation time. The solution of the integral transport equation within the isotropic scattering approximation is also studied within the DKT framework. The DKT formalism allows a considerable reduction in the dimensionality of the numerical representation of this problem, hence implying reduced computation costs. Finally, the DKE has been employed within the invariant-imbedding transport formalism to calculate the reflection (R) and transmission (T) probabilities for thermal neutrons incident upon a slab. Once again the DKT leads to a very considerable reduction in computation time and storage when compared with multigroup approaches. Numerical methods for solving the invariant imbedding-DKT equations for R and T have been developed and computationally verified as both accurate and efficient.