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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.
Kirk A. Mathews
Nuclear Science and Engineering | Volume 98 | Number 1 | January 1988 | Pages 41-50
Technical Paper | doi.org/10.13182/NSE98-01-41
Articles are hosted by Taylor and Francis Online.
A new neutron transport method, called discrete elements (LN), is derived and compared to discrete ordinates methods, theoretically and by numerical experimentation.The discrete elements method is based on discretizing the Boltzmann equation over a set of elements of angle. The zeroth and first angular moments of the directional flux, over each element, are estimated by numerical quadrature and yield a flux-weighted average streaming direction for the element. Data for this estimation are fluxes infixed directions calculated as in SN. The spatial quadrature then propagates the element flux in this “steered” direction, strongly ameliorating ray effect. The discrete elements method is shown to be more cost-effective than discrete ordinates, in terms of accuracy versus execution time and storage, for the cases tested. In a two-dimensional test case, a vacuum duct in a shield, the LN method is more consistently convergent toward a Monte Carlo benchmark solution.
