Perspectives Gained From the Individual Plant Examination of External Events (IPEEE) Program - Final Report (NUREG-1742, Volume 1)

On this page:

Download complete document

Publication Information

Manuscript Completed: September 2001
Date Published: April 2002

Division of Risk Analysis and Applications
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Availability Notice


On June 28, 1991, the U.S. Nuclear Regulatory Commission (NRC) issued Supplement 4 to Generic Letter (GL) 8 8-20, "Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities, 10 CFR 50.54(f)," and NUREG-1407, "Procedure and Submittal Guidance for the Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities." Specifically, the NRC requested that each licensee perform an IPEEE to identify and report to the NRC all plant-specific vulnerabilities to severe accidents caused by external events. The external events to be considered in the IPEEE included seismic events; internal fires; and high winds, floods, and other (HFO) external initiating events including accidents related to transportation or nearby facilities and plant-unique hazards. All of the currently operating U.S. nuclear power plants have completed their assessments and submitted their analyses for NRC review.

The objective of the NRC's IPEEE submittal reviews was to ascertain whether the licensees' IPEEE processes were capable of identifying severe accident vulnerabilities to such external events, and implementing cost-effective safety improvements to either eliminate or reduce the impact of those vulnerabilities. However, the reviews did not attempt to validate or verify the results of a licensee's IPEEE.

The primary purpose of this report is to document the perspectives gleaned from the technical reviews of the IPEEE submittals. These include a description of the overall IPEEE process and findings; conclusions regarding the dominant risk contributors for the major areas of evaluation (i.e., seismic events, fires, and HFO events); an overview of plant improvements made by licensees as a result of the IPEEE program; a description of the overall strengths and weaknesses in the licensees' implementation ofthe IPEEE evaluation methodologies; and an assessment of the overall effectiveness in meeting the IPEEE objectives, including the extent to which licensees have met the intent of Supplement 4 to Generic Letter 88-20. Volume 1 of this report includes general IPEEE perspectives while Volume 2 includes detailed tables with plant-specific information relevant to the IPEEE program.

Page Last Reviewed/Updated Wednesday, March 24, 2021