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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.
W. L. Filippone, S. P. Monahan, S. Woolf, J. C. Garth
Nuclear Science and Engineering | Volume 105 | Number 1 | May 1990 | Pages 52-58
Technical Paper | doi.org/10.13182/NSE90-A19212
Articles are hosted by Taylor and Francis Online.
The Sn method for solving the Spencer-Lewis equation for electron transport has been extended to treat three-dimensional multiregion problems. The flux continuity condition, which holds when the flux is expressed as a function of path length for single material region problems, is generalized for multiregion problems by reexpressing the flux as a function of energy. Expressing the fluxes in terms of fixed energy increments, independent of material, rather than fixed path length increments, results in a set of Sn/diamond-difference equations that are nearly identical in form to conventional Sn/diamond-difference equations. The Sn method is then applied to calculate electron energy deposition due to 200-keV electron beams incident on problem geometries typical of silicon and gallium-arsenide semiconductor microelectronic devices. The energy deposition results were found to compare well with results of ACCEPT Monte Carlo calculations. Computer run times required for the Sn calculations were found to be lower than that required for Monte Carlo by factors ranging from 30 to 50.
