Abstract: In this paper, filtering property and pressure drop performances of the in-containment refueling water storage tank(IRWST) sump strainers system were studied. The research work was performed with experimentation and numerical simulation methods, including experimental research on the downstream debris concentration and the pressure drop analysis of the strainers. The results show that the downstream debris concentration is 368 ppm under accidental condition, and the pressure drop of the RIS & HER sump strainers is 3.533 kPa and 3.631 kPa, respectively, which meet the functional requirements of the downstream debris concentration (480 ppm) and system pressure drop (5.6 kPa) of the IRWST sump strainers.