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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.
P. I. Johansson, B. Holmqvist
Nuclear Science and Engineering | Volume 62 | Number 4 | April 1977 | Pages 695-708
Technical Paper | doi.org/10.13182/NSE77-A15210
Articles are hosted by Taylor and Francis Online.
The prompt fission neutron spectrum emitted by a sample of 235U irradiated with 0.53-MeV neutrons has been measured in the 0.6- to 15-MeV energy range by using time-of-flight (TOF) techniques. In the present work, a major effort was made to obtain an accurate experimental determination of the energy response and efficiency function of the neutron detector over the entire neutron energy range of interest. For this purpose, the TOF spectrometer was calibrated with respect to energy in the 0.5- to 21-MeV range by observing neutron groups from various nuclear reactions. The energy dependence of the neutron detector efficiency was determined by observing the angular distributions of the H(n,n)H process in the 1- to 15-MeV energy range. The overlapping 0.6- to 3-MeV energy range was covered by the T(p,n)3He reaction. The result of the fission neutron spectrum measurements has been used to find a suitable distribution function describing the data in the entire energy interval. The best description was obtained with the distribution N1(E) exp(–1.02E)sinh(2.32E)1/2.
