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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. P. Poenitz, L. R. Fawcett, Jr., D. L. Smith
Nuclear Science and Engineering | Volume 78 | Number 3 | July 1981 | Pages 239-247
Technical Paper | doi.org/10.13182/NSE81-1
Articles are hosted by Taylor and Francis Online.
The capture cross section of 238U was measured using the activation technique and 235U(n, f) and 197Au(n, γ) as reference cross sections. Capture events were measured by detection of two prominent gamma-ray transitions in the decay of the 239U daughter nuclide, 239Np, employing a high-resolution Ge(Li) detector. The system was calibrated with the absolutely calibrated alpha-particle emitter, 243Am, which decays to 239Np. Cross-section measurements were carried out at thermal neutron energy and in the neutron energy range from 30 keV to 3 MeV. Emphasis in the higher keV range was on absolute values between 0.14 keV and 1 MeV where the 238U(n, γ) cross section and its ratio to 235U(n, f) are not very sensitive to energy scale uncertainties, and the 238U(n, f) cross section is small. Background from fission products was found to restrict the accuracy of the measured data at energies 1.5 MeV.
