A PRELIMINARY APPROACH TO HUMAN RELIABILITY ANALYSIS FOR EXTERNAL EVENTS WITH A FOCUS ON SEISMIC HRA

摘要

Substantial research has been performed to-date to develop and improve methods to perform Human Reliability Analysis (HRA) in support of Probabilistic Risk Assessment (PRA). Existing HRA methods, however, were developed primarily for internal events PRA. These methods often contain underlying assumptions that may or may not be applicable to the challenging, new environment following an external initiating event such as a seismic event, external flood or hurricane. Furthermore, there is a wide variation in existing methods for external events HRA. Variation exists between methods used for different hazard types as well as plant-to-plant variation for evaluation of a given hazard type. The reliability of operator actions following an external initiating event is a topic that has increased relevance and attention following the seismic-induced tsunami at Fukushima Daiichi. This event has prompted licensees in the U.S.A., and internationally, to reexamine their plant's risk profile and the plant's ability to prevent and/or mitigate damage following external initiating events. In support of the industry initiatives to evaluate and prepare for external initiating events, the Electric Power Research Institute has developed a preliminary approach to analyze the reliability of operator actions following external initiating events, with a specific focus on seismic events. The preliminary approach has been published in EPRI technical update 1025294 in December 2012, and provides a framework for HRA, a general screening approach and a detailed quantification approach which is an adaptation of the EPRI HRA methodology. This paper provides a summary of the EPRI Seismic HRA approach.