Development of a quantitative resilience model for nuclear power plants

The causes of the Fukushima nuclear power plant (NPP) accident have been identified as not only technical factors such as the structure, system, and equipment design, but also inadequate management of the human and organizational factors, which were the major contributors to exacerbating the beyond design basis accident. After the accident, the safety paradigm was changed to address the failure of equipment as well as effective factors for safety. Resilience engineering is a relatively new paradigm for safety management that focuses on how to cope with complexity under pressure or disturbance to achieve success, addressing the limitations of existing safety analysis measures. This study aimed to develop a quantitative resilience model for the NPP using a modified NPP resilience model based on the Model of Resilience in Situation developed by the Électricité de France. Event reports for Korea NPPs were analyzed according to the perspectives of Safety-I and Safety-II, and statistical analysis was performed to identify the relations in the resilience model. Through this analysis, the quantitative relationship of the element in the resilience model was determined, and the quantitative resilience model was developed. The developed quantitative resilience model was also validated through a statistical method. Our results provide a new method for safety assessment in NPPs, which can complement the conventional safety assessment. The proposed method is expected to be an index for evaluating the integrity of safety management in Korean NPPs.