A loss-of-coolant accident (LOCA) is one of the basic design considerations for nuclear reactor safety analysis. A LOCA induces propagation of a depressuriza-tion wave in the coolant, exerting hydrodynamic forces on structures via fluid–structure interaction (FSI). The analysis of hydrodynamic forces on the core structures during a LOCA process is indispensable. We describe the imple-mentation of a numerical strategy for prestressed struc-tures. It consists of an initialization and a restarted transient analysis process, all implemented via the ANSYS Work-bench by system coupling of ANSYS and Fluent. Our strategy is validated by making extensive comparisons of the pressures, displacements, and strains on various loca-tions between the simulation and reported measurements. The approach is appealing for dynamic analysis of other prestressed structures, owing to the good popularity and acknowledgement of ANSYS and Fluent in both academia and industry.