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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.
G. S. Sidhu, W. E. Farley, L. F. Hansen, T. Komoto, B. Pohl, C. Wong
Nuclear Science and Engineering | Volume 66 | Number 3 | June 1978 | Pages 428-433
Technical Note | doi.org/10.13182/NSE78-A27226
Articles are hosted by Taylor and Francis Online.
We have remeasured the spectra for the neutron and secondary gamma rays due to a 14-MeV neutron source by replacing liquid nitrogen, used in our earlier work, with liquid air (LA) as the transport medium. The deuterium-tritium neutron source was located at the center of the sphere (129.3-cm radius) of LA (20.7 at. % O2 remainder N2). Scintillation detectors were located at a distance from the sphere. Using time-of-flight techniques, we obtained approximate neutron energy information by measuring the time-of-arrival of neutrons at the detectors. We also measured, in a 60-ns time window before the arrival of 14-MeV neutrons, the gamma-ray spectrum that results from nonelastic neutron interactions in LA. To compare the measured spectra with code calculations, we folded the detector efficiencies and experimental parameters into the calculated output of TARTNP, the coupled neutron-photon Monte Carlo transport code of Lawrence Livermore Laboratory. The calculated spectra for gamma rays and neutrons and the calculated radiation doses show good agreement with the measurements. The results of this work provide a benchmark point on a radiation dose versus range-in-air curve obtained by the TARTNP calculations.