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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.
S. A. Dupree, J. E. Morel
Nuclear Science and Engineering | Volume 78 | Number 3 | July 1981 | Pages 284-293
Technical Paper | doi.org/10.13182/NSE81-A20305
Articles are hosted by Taylor and Francis Online.
Adjoint transport calculations provide an efficient means for determining the response of various targets to external sources of radiation. In the present paper, the fission response of a small, cylindrically symmetric target to a plane-incident beam of neutrons is determined through three techniques: (a) a discrete summation using EQN quadratures, (b) a discrete summation using Lobatto quadratures, and (c) an exact integral of a spherical harmonic interpolation of EQN angular fluxes. To calculate the fission response of the sample target to a reasonable degree of accuracy, the first method requires the use of quadratures of order at least S16, while the second method requires only S8. The general utility of the third method is hampered by a rapid increase in complexity with increasing quadrature order; however, for the present example, in which a low-order quadrature solution provides reasonably accurate scalar fluxes, interpolation of S2 angular fluxes yielded a response of comparable accuracy to the S8 Lobatto solution.