DIFF, a code to prepare neutron diffusion theory parameters from the results of the code WDSN.
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Date
1967-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Atomic Energy Commission
Abstract
With a solution of the multigroup neutron transport equation available for a problem in one dimensional geometry, diffusion theory parameters are determined so as to reproduce in diffusion theory the essential characteristics of the transport solution. Calculation of a more realistic reactor configuration can then be attempted in diffusion theory. Diffusion coefficients, taken as constant within a uniform region, can be determined so that the diffusion flux is an optimum fit to the transport flux. As an option the conventional 1/3Σtr can be used. The homogeneous boundary condition is found from a diffusion theory calculation which uses the transport net current as an inhomogeneous boundary condition. The homogeneous boundary condition forces the diffusion theory to reproduce exactly the transport leakage and multiplication constant. A discontinuity in the diffusion flux is permitted at interfaces between different materials. Interface conditions, if applied, guarantee that any reaction rate, integrated over the volume of a uniform region, is preserved by the diffusion theory. The DIFF code uses the results of the WDSN transport code to calculate diffusion theory parameters for the CRAM diffusion code.
Description
Keywords
Neutron diffusion equation, Neutron transport theory, Energy, Transport theory
Citation
Spinks, N. & Manning, G. (1967). DIFF, a code to prepare neutron diffusion theory parameters from the results of the code WDSN. (AAEC/E/174). Lucas Heights, NSW: Australian Atomic Energy Commission Research Establishment.