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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.
Donald Bogart, Donald F. Shook, Daniel Fieno
Nuclear Science and Engineering | Volume 53 | Number 3 | March 1974 | Pages 285-303
Technical Paper | doi.org/10.13182/NSE74-A23354
Articles are hosted by Taylor and Francis Online.
Integral tests of evaluated ENDF/B high-energy cross sections have been made by comparing measured and calculated neutron leakage flux spectra from spheres of various materials. An Am-Be(α,n) source was used to provide fast neutrons at the center of the test spheres of beryllium, polyethylene, lead, niobium, molybdenum, tantalum, and tungsten. The absolute leakage flux spectra were measured in the energy range from 0.5 to 12 MeV using a calibrated NE-213 liquid scintillator neutron spectrometer. Absolute calculations of the spectra were made using Version-Ill ENDF/B cross sections and an Sn discrete-ordinates multigroup transport code., Generally excellent agreement was obtained for beryllium, polyethylene, lead, and molybdenum, and good agreement was observed for niobium although discrepancies were observed for some energy ranges. The poor comparative results obtained for tantalum and tungsten are attributed to unsatisfactory nonelastic cross sections. The experimental sphere leakage flux spectra are tabulated and serve as possible benchmarks for these elements against which reevaluated cross sections may be tested.