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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.
J. T. Mihalczo
Nuclear Science and Engineering | Volume 49 | Number 4 | December 1972 | Pages 489-504
Technical Paper | doi.org/10.13182/NSE72-A22568
Articles are hosted by Taylor and Francis Online.
Cylinders and cylindrical annuli of uranium metal (93.15 wt% 235U), with diameters varying from 7 to 15 in., were assembled to delayed criticality with graphite reflectors varying in thickness up to 18 in. or with an effectively infinite thickness polyethylene on all outer surfaces. In one series of measurements a polyethylene reflector was also placed adjacent to only one flat surface of the cylinders. The multiplication factor calculated by both Sn transport and Monte Carlo methods, with various sets of cross sections agreed very well with the experimental values. As a result of the high order of Sn and the large number of spatial intervals required, the computing time for the transport theory calculations was a factor of 10 larger than that required for the Monte Carlo calculations with standard deviations of 1%.
