An analytical solution for the consideration of the effect of adjacent fuel assemblies; extension to hexagonal VVER-440 type fuel assemblies

A new analytical method is described to deal with the Leakage Environmental Effect. The method is based on the one dimensional analytical solution of the two-group diffusion equation for two adjacent fuel assemblies. The quality of the results for this highly efficient method is demonstrated for quadratic fuel assemblies. In additional tests the transferability of the concept to hexagonal VVER-440 type fuel assemblies is shown.