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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.
N. N. Kaushal, B. K. Malaviya, M. Becker, E.T. Burns, E. R. Gaerttner
Nuclear Science and Engineering | Volume 49 | Number 3 | November 1972 | Pages 330-348
Technical Paper | doi.org/10.13182/NSE72-A22546
Articles are hosted by Taylor and Francis Online.
Fast neutron spectra in a cuboidal assembly of uranium depleted in the 235U isotope have been measured for the purpose of providing integral checks on cross-section data pertinent to fast reactor development. Spectral measurements have been made at three different radial distances and several different angles, and cover an energy range from 10 keV to 10 MeV. The experimental spectra are compared with Sn transport calculations involving ENDF/B-I, ENDF/B-II, KEDAK (from Karlsruhe) files, and a multigroup set from Argonne National Laboratory and conclusions are drawn as to the adequacy of these data for predicting measured spectra. Extensive use is made of the continuous slowing down theory to pinpoint specific areas of uncertainty in the cross-section data. From a comparison of the experimental spectra with the calculations, it is concluded that the neutron capture cross-section data in the 238U ENDF/B files should be lowered by about 10% in the range 10 to 40 keV. Additionally, the slowing down effectiveness of inelastic scattering in the range 40 to 500 keV should be lowered by about 25%. Discrepancies among various data files are also observed in the inelastic slowing down effectiveness in the range 1 to 2 MeV.
