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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.
Shoji Watanabe, Kojiro Nishina
Nuclear Science and Engineering | Volume 86 | Number 3 | March 1984 | Pages 283-296
Technical Paper | doi.org/10.13182/NSE84-A17557
Articles are hosted by Taylor and Francis Online.
A stability analysis using a one-group model is presented for a coupled-core system. Positive prompt feedback of a γpj form is assumed, where pj is the fractional power variation of core j. Prompt power variations over a range of a few milliseconds after a disturbance are analyzed. The analysis combines Liapunov's method, prompt jump approximation, and the eigenfunction expansion of coupling region response flux. The last is treated as a pseudo-delayed neutron precursor. An asymptotic stability region is found for pj. For an asymmetric flux variation over a system of two coupled cores, either pI or pII can slightly exceed, by virtue of the coupling effect, the critical value (β/γ − 1) of a single-core case. Such a stability region is increased by additional inclusion of the coupling region fundamental mode in the treatment. The coupling region contributes to stability through its delayed response and coupling. An optimum core separation distance for stability is found.
