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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.
L. Green, J. A. Mitchell
Nuclear Science and Engineering | Volume 54 | Number 1 | May 1974 | Pages 18-27
Technical Paper | doi.org/10.13182/NSE74-A23389
Articles are hosted by Taylor and Francis Online.
Neutron scattering cross sections have been measured for 233U and 232Th, using rolled metal samples, in a moderated spectrum from a 5-mg 252Cf source. The scattered neutrons were detected by two 3He detectors in an annular geometry. The experimental data were corrected for thermal and epithermal fissions, epi-thermal scattering, air scattering, room background, and self-absorption. The self-absorption corrections for the four 233U targets, covering a wide range in thickness, were obtained from Monte Carlo calculations. Absorption corrections for the two 233Th targets were avoided by using standards having the same absorption thicknesses. The results obtained were 12.30 ± 0.70 b for 233U and 12.78 ± 0.30 b for 232Th relative to vanadium with an assumed scattering cross section of 5.02 ± 0.10 b. The corresponding values for the ENDF/B-III file are 14.06 and 11.92 b, respectively.
