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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.
R. L. Macklin, J. Halperin
Nuclear Science and Engineering | Volume 64 | Number 4 | December 1977 | Pages 849-858
Technical Paper | doi.org/10.13182/NSE77-A14500
Articles are hosted by Taylor and Francis Online.
Neutron capture by isotopically purified 232Th was measured at the Oak Ridge Electron Linear Accelerator. The pulse-height weighting method was used with small liquid scintillators to measure the prompt gamma-ray energy release following neutron capture. Resonance parameters were derived up to 10 keV. The average radiative width was (19.8 ± 0.2 statistical ± 0.4 systematic) meV for 50 resonances in the 2.6- to 4.0-keV interval. Strength functions 104S0 = 0.365 ± 0.024, 104 S1 = 1.078 ± 0.057, 104S2 > 0.842 ± 0.084, and y/D0 = 0.0198/(13.24 ± 0.71) were found to fit the average cross section well (to 105 keV) when allowance was made for p-wave inelastic competition above the ∼50-keV threshold. While the values stated gave the best fit (from 2.6 to 105 keV) when all four were allowed to vary, it is likely that “acceptable” fits could be forced for other values. Recent evaluations of the cross section range from 8 to 50% higher than results reported here.
