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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.
E. Rich, Gilles Noguere, C. De Saint Jean, A. Tudora
Nuclear Science and Engineering | Volume 162 | Number 1 | May 2009 | Pages 76-86
Technical Paper | doi.org/10.13182/NSE162-76
Articles are hosted by Taylor and Francis Online.
For the modeling of the neutron cross sections, three energy ranges can be distinguished. The resolved resonance range can be interpreted in terms of single-level, multilevel, Reich-Moore, or R-matrix parameters. The unresolved resonance range (URR) is described with the average R-matrix and Hauser-Feshbach formalisms. For the high energies ("continuum"), optical model parameters are used in association with statistical and preequilibrium models. One of the main challenges of such a work is to study the consistency of the average parameters obtained by these different calculations. With the ESTIMA and SPRT methods, we provide a set of parameters for partial s-waves and p-waves (strength functions Sl and effective potential scattering radius R'). However, accurate analysis of the URR domain needs more information than parameters R' and Sl associated with orbital moments l = 0 and l = 1. Using links between the average R-matrix formalism and the optical model calculations, we propose a generalization of the SPRT method for l > 1 and a new description of the URR domain in terms of Sl and RlJ.
