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A nodal diffusion technique for synthetic acceleration of nodal S /sup n/ calculations

Journal Article · · Nucl. Sci. Eng.; (United States)
OSTI ID:6073359

A diffusion theory method is developed for synthetic acceleration of nodal S /sub n/ calculations in multidimensional Cartesian geometries. The diffusion model is derived from the spatially continuous diffusion equation by applying spatial approximations that are P expansions of the corresponding approximations made in solving the transport equation. The equations of the diffusion model are formulated in a way that permits application of existing and highly efficient nodal diffusion theory techniques to their numerical solution. Test calculations for several benchmark problems in X-Y geometry are presented to illustrate the efficiency and stability of the acceleration metho when applied to a ''constant-linear'' nodal transport approximation. The method is shown to yield pointwise flux convergence of 10 U in fewer than ten synthetic iterations for all problems considered and to require substantially less computational effort than unaccelerated solutions.

Research Organization:
Argonne National Laboratory, Argonne, IL
OSTI ID:
6073359
Journal Information:
Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 90; ISSN NSENA
Country of Publication:
United States
Language:
English