Modelling of CANDU Reactivity Mechanisms with DRAGON

Abstract

The integral transport equation is solved in 3-D supercell geometries containing zones of mixed cylindrical and rectangular geometries. A symmetric two-bundle model allows most of the surfaces to be located in the moderator regions, thus reducing discrepancies introduced by the assumption of isotropic boundary currents. Efficient algorithms for computation and normalization of collision probabilities pertinent to these supercell models are fully described. Numerical results for adjuster rods and liquid zone controllers of the G2 reactor are presented.