Performance analysis and test on the KAERI devised spacer grids for PWRs

Spacer grid which is one of the most important structural components in a pressurized light water reactor fuel assembly supports the fuel rods laterally and vertically. Based on design experiences and by scrutinizing the design features of advanced nuclear fuels and the international patents of spacer grids, KAERI has devised its own spacer grid shapes and acquired patents. In this study, a performance evaluation on two new spacer grid shapes devised by KAERI was carried out from mechanical/structural and thermohydraulic view points. And also a performance evaluation on two commercial spacer grid shapes was carried out for the sake of a comparison. The comparisons included the spring characteristics, fuel rod vibration characteristics, fretting wear resistance, impact strength characteristics, CHF enhancement, and pressure drop level of the spacer grid shapes. The comparison results have shown that the performances of the new spacer grid shapes are better or at least not worse than those of the commercial spacer grid shapes. (author)