The effect of fluid/structure interaction on the reactor internals responses for seismic and pipe break excitations

The effects of fluid-structure interaction between internals components due to their immersion in a confining fluid are considered for the dynamic response analysis. This paper calculates the hydrodynamic mass matrix which characterizes the fluid-structure interaction. Also, it provides the equations of motion containing hydrodynamic mass matrix and shows the method to solve them. The reactor internals responses for seismic and pipe break excitations are obtained for the case of with and without hydrodynamic couplings. The results show that seismic responses are higher for with-hydrodynamic couplings case than without case, but the pipe break responses show the opposite characteristics