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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.
W. Reed Johnson, Daniel H. Risher, James E. Rogers, William L. Thompson
Nuclear Science and Engineering | Volume 43 | Number 1 | January 1971 | Pages 32-41
Technical Paper | doi.org/10.13182/NSE71-A21243
Articles are hosted by Taylor and Francis Online.
Well-collimated beams of thermal-neutron-capture gamma rays from titanium and nickel, having average energies of about 6 and 8 MeV, respectively, were used to measure narrow-beam and total gamma-ray dose attenuation. Slab shields of lead, iron, and concrete were investigated for normal and oblique beam incidence. Total dose measurements were made by traversing an exposure-responsive detector through a plane behind and parallel to the shield. Monte Carlo and moments-method calculations were used to compare analytical and experimental total dose results. Good agreement was found for iron and concrete shields, but experimental results for the lead shield were higher than those predicted by the moments method by a factor of ∼1.2 for 6 MeV and ∼1.5 for 8 MeV. The reason for this disagreement is believed to be primarily bremsstrah-lung produced by energetic secondary electrons slowing down in lead.