Seismic Reliability Analysis of Complex Nuclear Power Plants by Explicit Time Domain Method

Abstract

Seismic reliability evaluation is of great importance in nuclear power engineering. The task remains an open challenge since it will involve the dynamic reliability analysis of large-scale complex structures of nuclear power plants on a global structure level under random seismic excitations, and in particular in the presence of structural uncertainties. The traditional random vibration methods with coupling treatment of the physical and the probabilistic evolution mechanism are hardly capable of executing such a difficult task. In this study, the explicit time-domain method (ETDM) developed in recent years is applied to the seismic global reliability analysis of complex nuclear power plants in consideration of structural uncertainties. The time-domain explicit expressions of the critical responses involved are first constructed based on the impulse response functions, and on this basis, the subsequent random vibration and reliability analysis can then be conducted just focusing on the selected critical responses. The uncoupling treatment of the two sets of mechanism in ETDM will lead to a real-sense dimensional reduction in terms of degrees of freedoms and time instants involved in random vibration analysis of structures, and thus a high efficiency in dynamic reliability analysis even in the presence of large-scale structural models. The engineering application to a nuclear power plant with over 2 million degrees of freedom, which is now being built in China, shows the feasibility of the present approach.