The study of seismic margins evaluation methodology

The objective of a seismic margin review of a plant is to determine if the plant can safely withstand an earthquake larger than the design-basis earthquake (DBE), namely the safe shutdown earthquake (SSE). In the mid-1980s, two different methodologies for the seismic margin assessment (SMA) of nuclear power plants were developed. One was developed by the Electric Power Research Institute (EPRI) (EPRI Method) and another was developed by the U.S. Nuclear Regulatory Commission (NRC) (NRC Method). This paper studied the SMA method, and has applied it in the passive nuclear plant. Practice show that compared with the NRC method and EPRI method, the AP1000 method is more convenient and operational.