Numerical modelling of rocking submerged spent fuel baskets under fluid–structure interaction

Rocking structures are widely used in seismic design, including in spent fuel storage and transportation baskets in nuclear power plants. Rocking and overturning analysis of such baskets is essential for evaluating structural safety under seismic loading. To provide radiation shielding and cooling, the baskets are submerged in water, leading to significant fluid–structure interaction (FSI) effects during earthquakes. Previous experiments have demonstrated that FSI strongly influences the rocking amplitude. Finite element models developed for racks are not suitable for simulating the rocking behavior of baskets. This study develops a finite element model that can simulate the rocking motion of an underwater basket and calculate parameters such as the time history of the rocking angle. The model results are validated by comparing them with our previous experimental data. In addition, a parametric study is conducted to investigate the effects of the friction coefficient and aspect ratio on the rocking response. The results indicate that as the width increases and the friction coefficient decreases, the rocking amplitude decreases while the sliding displacement increases. Notably, abrupt changes in rocking amplitude are observed within certain width and friction coefficient ranges. The findings provide valuable insights for designing and optimizing submerged rocking structures.