Effect of debris combination on flow resistance of fuel assemblies

Abstract After a LOCA, debris enters the fuel assemblies through the sump strainers of the containment, increasing the pressure drop of the fuel assemblies. Experimental study of the effects of debris passing through the strainers and settling in the reactor core within the fuel elements on the core cooling is crucial. The distribution, attachment and blockage of debris in a fuel assembly are studied by the experiment. The results show that the pressure drop is smaller than the driving head available for core cooling under a simulated cold leg break. Experiments on the AFA2G fuel assembly show that the pressure drop caused by the simultaneous introduction of three types debris into the fuel assembly is remarkable at the same flow rate and debris mass. However, the debris introduced to the fuel assembly in the order of particle debris, fiber de bris, and chemical debris can result in a lower pressure drop.