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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.
C. Lajeunesse, W. E. Moore, M. L. Yeater
Nuclear Science and Engineering | Volume 47 | Number 3 | March 1972 | Pages 349-364
Technical Paper | doi.org/10.13182/NSE72-A22420
Articles are hosted by Taylor and Francis Online.
The double-differential scattering cross section of polycrystalline natural uranium carbide (UC) has been measured for incident energies of 0.092, 0.135, and 0.159 eV. Inelastic scattering peaks corresponding to excitation energies of 0.013 and 0.045 eV were observed and are shown to belong to acoustic and optical modes of the UC lattice. A model has been developed using a normal mode analysis based on the Born and Von Kármán approximation, including noncentral forces and considering up to third-nearest neighbors. A theoretical scattering law has been derived based on this analysis. Resolution and multiple scattering effects have been calculated using a new Monte Carlo approach. After the application of these corrections, the double differential cross sections derived from the theoretical scattering law agree with the measurements. The variation of the specific heat with temperature is accurately predicted by the model. The total cross section was also measured for the energy range 0.006 to 3.5 eV. The Bragg peaks due to coherent scattering were resolved up to 0.05 eV. The total cross section calculated from our noncentral force model compares well with this measurement.