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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. T. Santoro, J. M. Barnes,R. G. Alsmiller, Jr.,J. D. Drischler
Nuclear Science and Engineering | Volume 92 | Number 4 | April 1986 | Pages 584-595
Technical Notes | doi.org/10.13182/NSE86-A18614
Articles are hosted by Taylor and Francis Online.
Measured and calculated neutron and gamma-ray energy spectra from ∼14-MeV neutrons streaming through a stainless steel duct having a length-to-diameter ratio of 4.6 are compared. The 1.45-m-long duct is imbedded in a concrete block. The spectra were measured with an NE-213 liquid scintillator as a function of detector location relative to the mouth of the duct. The calculated data were obtained using the Monte Carlo code MCNP and the discrete ordinates code DOT 4.3. The calculations were performed using a two-dimensional cylindrical model of the experiment with symmetry about the duct axis. The measured and calculated neutron and gamma-ray spectra are compared at two distances from the mouth of the duct and at detector locations on and off the duct axis. The neutron spectra calculated with MCNP agree with the measured data within ∼5 to 50% at all detector locations. The data calculated using the discrete ordinates method are in good agreement with the experiment for the cases where the detector is on axis but are in poor agreement at the off-axis detector locations. The gamma-ray spectra calculated with both radiation transport methods are in good agreement (∼5 to 25%, depending on photon energy) with the measured spectra.