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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.
D. V. Gopinath, K. Santhanam
Nuclear Science and Engineering | Volume 43 | Number 2 | February 1971 | Pages 186-196
Technical Paper | doi.org/10.13182/NSE71-A21266
Articles are hosted by Taylor and Francis Online.
A semi-analytical technique for the solution of neutron and gamma-ray transport in one-dimensional finite systems is developed. The method is applicable to multivelocity, multiregion systems with arbitrary degree of anisotropy. The transport equation is written in the form of coupled integral equations separating the spatial and energy-angular transmissions. Legendre polynomial approximation in the direction cosine, and discrete ordinate representation in energy and spatial domain are used for radiation source and flux. The space and energy-angle transmission kernels are evaluated analytically and the integral equations are then solved by a fast-converging iterative technique. For a plane parallel beam of radiation incident on a slab, the virgin and the first collision flux are not amenable to polynomial expansion due to the singularities. For such a case, up to second collision, source is computed analytically and then recourse is taken to polynomial approximation. The computer code ASFIT written on the basis of the above formulation is briefly described. Convergence studies with the polynomial approximation, energy and spatial mesh width are described.