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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.
Y. Harima, S. Tanaka
Nuclear Science and Engineering | Volume 90 | Number 2 | June 1985 | Pages 165-173
Technical Paper | doi.org/10.13182/NSE85-A17674
Articles are hosted by Taylor and Francis Online.
Exposure buildup factors for plane isotropic, point isotropic, and plane normal sources have been calculated using a discrete ordinates direct integration code, PALLAS-PL, SP-Br, in infinite and finite water shields in the 0.06- to 0.1-MeV range. The values of the attenuation kernel, Be-µr, are greater than unity at distances up to a few mean-free-paths in an infinite medium. The maximum value of Be-µr depends on the incident energy, and this effect reaches a maximum for a 0.08-MeV source. The implication that the dose rate with a shield is greater than without a shield should be noticed. Results of this study show, however, that the large degree of scattering in a low-z material, such as water, produces this effect. Buildup factors, energy spectra, and angular distributions were analyzed for three source geometries in the comparisons of scattered gamma-ray transport in infinite and finite water shields.