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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.
Toshikazu Takeda, Hironobu Unesaki, Toshihisa Yamamoto, Katsuya Kinjo, Toshio Sanda
Nuclear Science and Engineering | Volume 101 | Number 2 | February 1989 | Pages 179-184
Technical Paper | doi.org/10.13182/NSE89-A23606
Articles are hosted by Taylor and Francis Online.
Neutron streaming in a fast breeder reactor fuel subassembly caused by the double heterogeneity of the pin structure and the wrapper tube structure is estimated by double heterogeneous modeling. The neutron streaming is decomposed into three components: the pin-cell heterogeneity, the wrapper tube heterogeneity, and the homogenized fuel/wrapper tube subassembly effect. The streaming effect is evaluated based on the Benoist diffusion coefficient. The total streaming effect caused by the double heterogeneity structure of a fuel subassembly is found to be about −0.2% Δk/kk′ for keff, which is almost twice that obtained from the conventional pin-cell model of about −0.1% Δk/kk′.
