Structural Evaluation of Storage Racks According to Seismic Impact in SFP

In Korea, all spent fuel from pressurized water reactors (PWRs) is stored exclusively in spent fuel pools (SFPs). To expand storage capacity and sustain plant operation, high-density storage racks are being deployed. Ensuring the safety of spentfuel handling and storage entails establishing hypothetical accident scenarios and performing integrated evaluations of criticality, shielding, thermal performance, and structural behavior. This study evaluates the structural integrity of existing storage racks under seismic impact loads representative of current design-basis conditions. Specifically, the impact load predicted for newly installed racks was conservatively applied to the existing racks, and the resulting structural responses were assessed. The results show that the existing racks—owing to their thicker cells relative to the new racks—maintain sufficient structural integrity under the applied seismic impact load. In addition, a parametric assessment was conducted by varying the impact-load level and reducing rack-cell thickness to examine sensitivity and margin. At the SSE level, the buckling allowable remained satisfied for an ~9% increase in impact load and for an ~8% reduction in rack-cell thickness, indicating potential buckling only beyond those thresholds. These findings support safe SFP operation with high-density configurations.