Seismic periodic safety review of nuclear power plants in Korea

A periodic safety review (PSR) for Kori NPP is currently in process in Korea. Based on the research activities related to seismic re-evaluation for the existing NPPs, several technical issues are briefly introduced with countermeasures and improvements in this paper. Geological and seismological investigations, which include evaluation of capable faults and estimation of maximum credible earthquake for the NPP sites, were carried out in this study. Based on the recorded earthquake an attempt was made to develop a site-specific response spectrum. Earthquake monitoring network is installed on the outskirts of NPP sites to identify seismic activity. For reducing uncertainties of the probabilistic seismic hazard assessment (PSHA), a research work was performed. Seismic qualification of equipments for the unresolved safety issue (USI) A-46 NPPs is introduced. The post-earthquake procedure including selection of base lines and a seismic damage indicator is developed to provide guideline for better post-shutdown inspection and test. A study to evaluate tsunamic risk is introduced. In the future, further implementation to resolve seismic safety issues is to be made. (authors)