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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.
M. L. Williams, M. Asgari
Nuclear Science and Engineering | Volume 121 | Number 2 | October 1995 | Pages 173-201
Technical Paper | doi.org/10.13182/NSE95-1
Articles are hosted by Taylor and Francis Online.
A procedure is presented to obtain a continuous-energy representation of the neutron spectrum using one-dimensional discrete ordinates calculations with a combination of multigroup (MG) and pointwise (PW) nuclear data. This provides the capability of determining the fine-structure energy distribution of the angular flux and flux moments within the resonance range as well as the smoother spectrum in the high- and thermal-energy ranges. A new method called a submoment expansion is developed to accurately calculate the Legendre moments of the elastic scatter source for the PW transport calculation, and the coupling between the MG and PW calculations is discussed in detail. The continuous-energy flux spectra can be utilized as problem-dependent weighting functions to process self-shielded MG cross sections for reactor physics and/or criticality safety analysis. This calculational method has been implemented in a new PW transport code called CENTRM that can be executed as a module in the AMPX and SCALE computer code packages. An example application using ENDF/B-VI cross-section data to analyze critical benchmarks is presented.