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NRC proposes changes to its rules on nuclear materials
In response to Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission,” the NRC is proposing sweeping changes to its rules governing the use of nuclear materials that are widely used in industry, medicine, and research. The changes would amend NRC regulations for the licensing of nuclear byproduct material, some source material, and some special nuclear material.
As published in the May 18 Federal Register, the NRC is seeking public comment on this proposed rule and draft interim guidance until July 2.
Peter Grimm, Menashe Aboudy, Alex Galperin, Meir Segev
Nuclear Science and Engineering | Volume 122 | Number 3 | March 1996 | Pages 395-406
Technical Paper | doi.org/10.13182/NSE96-A24174
Articles are hosted by Taylor and Francis Online.
Preliminary to implementing a pin power reconstruction scheme in the nodal core calculations of the ELCOS system, the “main stream” methods and elements thereof were tested against fine-mesh calculations of a number of benchmark “small cores” consisting of uranium, controlled uranium, and mixed-oxide assemblies. Overall, the results do not clearly favor one of the methods. However, test details conduce us to prefer the 32-term expansion for corner-point fluxes over their determination by the separability assumption, and the 21-term expansion of the intranodal flux over the 13-term expansion. There is little difference whether the factorization of the pin power distribution into global and form factors is imposed on the group fluxes or on the power. Data transfers and matrix inversions connected with the many-term flux expansions slow down the nodal calculation. This condition may be alleviated in some cases by an approximation leading to fewer matrix inversions.