American Nuclear Society
Home

Home / Publications / Journals / Nuclear Science and Engineering / Volume 47 / Number 1

Anisotropic Diffusion Coefficient in Generalized X, Y Geometry: Theory and Application to Diffusion Codes

M. Michelini

Nuclear Science and Engineering / Volume 47 / Number 1 / January 1972 / Pages 116-126

Technical paper / dx.doi.org/10.13182/NSE72-A28424

In the study of the possibilities of improving the accuracy of diffusion calculations, a point-by-point formulation has been established of the diffusion coefficient DK(x,y) most appropriate to heterogeneous systems comprised of low absorbing media, that is a formulation which contains all the information obtainable from such a system. Since the actual size of each medium is taken into account, this formulation can predict the proper diffusion coefficients even within cavities. In this work three coefficients, Dx, Dy, and Dz, of anisotropic diffusion are derived for any rectangular elementary region imbedded in a generalized X, Y geometry. They enable us to perform more accurate diffusion calculations in all cases where classical diffusion can be used. In addition, anisotropic diffusion allows the study of nonhomogenized cavities. Finally, numerical calculations confirm that anisotropic diffusion is very suitable in many pròblems.