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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. T. Santoro, R. G. Alsmiller, Jr., J. M. Barnes, G. T. Chapman, J. S. Tang
Nuclear Science and Engineering | Volume 80 | Number 4 | April 1982 | Pages 586-602
Technical Paper | doi.org/10.13182/NSE82-A18972
Articles are hosted by Taylor and Francis Online.
Integral experiments that measure the streaming of ∼14-MeV neutrons through a 0.30-m-diam iron duct (length-to-diameter ratio ∼ 3) imbedded in a concrete shield have been carried out at the Oak Ridge National Laboratory. Calculated and measured neutron and gamma-ray energy spectra are compared at 16 detector locations on and off the cylindrical axis of the duct. The measured spectra were obtained using an NE-213 liquid scintillator detector with pulse-shape discrimination to simultaneously resolve neutron and gamma-ray events. The calculated spectra were obtained using a computer code network that incorporates two radiation transport methods: discrete ordinates (with P3 multigroup cross sections) and Monte Carlo (with continuous point cross sections). The two radiation transport methodologies are required to properly account for neutrons that single scatter from the duct to the detector. The calculated and measured outgoing neutron energy spectra above 850 keV agree within 5 to 50% depending on detector location and neutron energy. The calculated and measured gamma-ray spectra above 750 ke V are also in favorable agreement, ∼5 to 50%, depending on detector location and gamma-ray energy.