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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.
A. N. Verma, Balesh Verma, Feroz Ahmed, L. S. Kothari
Nuclear Science and Engineering | Volume 72 | Number 2 | November 1979 | Pages 160-174
Technical Paper | doi.org/10.13182/NSE79-A19461
Articles are hosted by Taylor and Francis Online.
To study the anisotropy in scattering of thermal neutrons in beryllium, we have calculated elastic as well as inelastic differential cross sections. Anisotropy in elastic scattering is studied by replacing the δ function by a Gaussian function of suitable width. To study the anisotropy in inelastic scattering, we have calculated one-phonon coherent inelastic differential cross sections. The differential cross sections for the one- and two-phonon processes have also been calculated in the incoherent approximation. We have also expanded the angle dependence of cross section in terms of the Legendre polynomials. Using the above differential cross sections, the intensity of scattered neutrons in various angular directions has been calculated, and the results have been compared with the corresponding observed results of Aizawa et al. Calculated results are found in good agreement with the corresponding observed results. We have investigated the effect of anisotropy in scattering on steady-state angular spectra inside small beryllium assemblies. The calculated results have been compared with the observed results of Lake and Kallfelz and also with those obtained in the isotropic scattering approximation of Garg et al. It is found that the calculated spectra in the first angular direction (θ1 ≃ 28 deg) at various distances from the source plane are in better agreement with the corresponding observed results in the entire energy range than those obtained in the isotropic scattering approximation.
