ANALYSIS OF FUEL RODS SLIDING IN SPACER GRIDS OF A FUEL ASSEMBLY IN A WWER-1000 REACTOR

摘要

Sliding of fuel rods and of guide channels in spacer grids of a fuel assembly in a WWER-1000 reactor during an increase in the reactor power and in the course of cooling-down is investigated. A solution algorithm based on the initial stress method is used to solve a nonlinear sliding problem. Strain-stress curves are presented for the fuel rods and guide channels with account taken of their displacement relative to the spacer grids. The effect of initial strain in grid cells on the residual stresses and deformations of the fuel rods and the channels is demonstrated.