Seismic IPEEE industry insights

The United States Nuclear Regulatory Commission initiated a formal review of the seismic margin of all operating nuclear power plants in the US with the issuance in 1991 of Generic Letter 88-20, Supplement 4 (‘Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities’). Virtually all of the US nuclear utilities have submitted their responses for seismic IPEEE and these submittals are in the process of being reviewed by the NRC. The objective of this paper is to provide an industry perspective on the results and the insights obtained from the utility seismic IPEEE submittals.