ICONE23-1604 FUEL ASSEMBLIES BLOCKAGE ANALYSIS DURING LOSS OF COOLANT ACCIDENTS IN PWR

Abstract

During the recirculation after postulated loss of coolant accident (LOCA) scenario in PWR, debris that generated in the containment might challenge the core flow path and cause the head-loss across the fuel assemblies. Experimental loop and test section are designed for the debris-loading head-loss tests of fuel assemblies. The goal of the testing is to study the relationship of debris, flow rates and head-loss. Pre-simulation of the blockage in fuel flow path is performed using CFD code. A simplified 2×2 grid model of rod bundles is used to compute and compare the flow conditions under varies flow velocities and blockage percentages. The results demonstrate that the pressure will sharply drop after the flow past the mixing vane of the grid, and the head-loss will increase with the increasing blockage rate and flow velocity. The results match the objective law that the velocity is high in flow channels and low in fuel rods whether the blockage is occurred or not.