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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.
R. M. Versluis, A. J. Mockel
Nuclear Science and Engineering | Volume 58 | Number 1 | September 1975 | Pages 75-88
Technical Paper | doi.org/10.13182/NSE75-A26768
Articles are hosted by Taylor and Francis Online.
In this paper an improved degenerate kernel is obtained and subsequently used instead of the exact thermalization kernel for the calculation of thermal-neutron densities in a heterogeneous reactor lattice.The degenerate kernel is composed of a number of functions, some of which are obtained by conserving speed moments of the kernel while the remaining functions are chosen so as to reproduce scattering probabilities involving epithermal energies. The degenerate kernel satisfies the detailed balance strictly and, as opposed to conventional degenerate kernels, shows the desirable feature of improved accuracy when the number of terms in the degenerate kernel is increased.This degenerate kernel is employed to compute thermal-neutron spectra in cylindricized unit cells by solving the integral transport equation for the scalar neutron density. For this purpose the DESMOS code was developed. The results of these calculations are compared with the analogous THERMOS code results. DESMOS proves to be accurate and its speed of execution compares favorably with that of THERMOS.
