Hexagonal-geometry fast-reactor nodal modeling

Several nodal methods have been developed for simulating power distributions in thermal reactors, and have been tested for applicability to fast reactor problems. The testing was performed in rectangular geometry. Since fast reactor configurations typically use hexagonal assemblies, the most promising of the techniques tested was extended to hexagonal geometry and applied to a range of test cases. The approach selected was the generalized coarse mesh procedure (GCMDT) using different interpolation parameters in different zones