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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.
Alan V. Jones
Nuclear Science and Engineering | Volume 105 | Number 2 | June 1990 | Pages 105-122
Technical Paper | doi.org/10.13182/NSE90-A23741
Articles are hosted by Taylor and Francis Online.
One of the more severe scenarios for a single subassembly accident in a liquid-metal fast breeder reactor is the formation of a bottled-up pool of fuel and steel in the assembly and its subsequent lateral discharge into a neighbor through a breach in the can wall. Most of the calculations and experiments to investigate this scenario have assumed that the discharge is single phase. Recent experimental evidence from SCARABEE suggests that the discharge is more likely to be two phase. A series of SIMMER calculations has been performed to examine the major features of a two-phase fuel discharge into a rod bundle. Flashing is found to reduce the mass flux of the discharge; the vapor so generated then accelerates the liquid in the discharge, resulting in higher melt velocities and generally deeper penetration of the discharge into the bundle before plugging occurs as compared with the singlephase case.