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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. D. Lawrence, J. J. Dorning
Nuclear Science and Engineering | Volume 64 | Number 2 | October 1977 | Pages 492-507
Technical Paper | doi.org/10.13182/NSE77-A27385
Articles are hosted by Taylor and Francis Online.
A smoothing and extrapolation method is applied to the point kinetics equations and the one-dimensional space-dependent reactor kinetics equations. The simple smoothing procedure is shown to be very efficient in reducing the oscillatory errors that occur when the standard Padé(1,1) and Crank-Nicholson approximations are applied to stiff reactor kinetics equations. Fourth-order accuracy is achieved by applying a single Richardson extrapolation (on a global basis) to the smoothed results obtained from values calculated using two time-step grids. The numerical results for point kinetics demonstrate that the method is particularly efficient for very stiff problems such as subcritical and delayed supercritical transients in fast reactors. Application of the method to two one-dimensional kinetics benchmark problems solved using a standard space-dependent computer code that utilizes the Crank-Nicholson approximation leads to significant reduction in the overall computational effort required to achieve a given accuracy.