Spent fuel of a nuclear power plant is generally stored in a wet storage pool. In case of seismic event, one has to insure the integrity of the spent fuel and structure holding it called spent fuel racks. In the present study, a simple model accounting for 12 racks is proposed and compared with experimental results involving reduced scale racks. Fluid-structure interactions are modeled in terms of added coupling mass and damping, and free surface effect is accounted for. Comparison between simulations and experimental results showed good agreement. In spite of the simplicity of the model simulation succeed to give a reasonable estimation of racks accelerations and was able to reproduced effect of excitation amplitude and water level.