Numerical Analysis of a Residual Heat Removal Piping System Subjected to Seismic Loading

Numerical Analysis of a Residual Heat Removal Piping System Subjected to Seismic Loading

The objectives of this study are to build a credible numerical model using SAP2000 for fragility analysis of a Residual Heat Removal(RHR) piping system, and to establish the load pattern of a cyclic loading test to identify the seismic vulnerability of the system. The RHR piping system selected for testing and numerical analysis was duplicated from a part of the RHR system in a nuclear power plant(NPP) in Taiwan, and this part is distributed between the floor of the reactor building(RB) and the wall of the reinforced concrete containment vessel(RCCV) of the sample NPP. The numerical model for the sample RHR piping system was developed, and a nonlinear time series analysis was conducted using input motions compatible with the floor response spectrum at the anchor points of the sample piping system subjected to a Safe Shutdown Earthquake(SSE). Based on the distribution of resultant inertial forces and the responses at critical locations of the piping system under an SSE, the magnitudes and locations of the equivalent concentrated static loads were determined and used in the pushover analysis to estimate the capacity of the RHR piping system. The numerical results will be verified by the aforementioned cyclic loading test. More studies are under way including shaking table tests and fragility analyses for the sample piping system to identify the seismic performance and risks associated with the system further.