면진 원전 면진-비면진구간 연결 배관의 내진성능 평가

Abstract

A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolatednuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system todemonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes butalso the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which werematched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of pipingsystem. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismicallyisolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stressresponse of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the designlevel earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to theintensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verificationof the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should beevaluated firstly.