Abstract
Objective: The aim of this study is to investigate the combination of function variability that has affected the development of the Fukushima accident and to identify potential risks of the emergency response system that directly related the Fukushima accident using the functional resonance analysis method. Background: From a traditional perspective (safety-1), safety management is implemented in a way that finds and solves the direct cause of the accident. In the Resilience engineering (safety-2), perspective, accidents or adverse outcomes are considered to emergent from the variability of performance rather than a linear causal relationship. The FRAM is a method of modeling system functions and finding potential risks in the system. Method: This study used the FRAM to analyze the accident response of the Fukushima case. In order to identify the accident response system of the Fukushima, we investigated the existing Fukushima accident reports and analyzed the nuclear power plant structure report. Based on these results, we modeled the accident response system of Fukushima accident. Through the FRAM model, we analyzed the variability of the system functions and identified the risks that the combinations of variability might cause. Results: Through the retrospective analysis, we identified the effect of the combinations of variability of system functions on the accident development process. In this study, we present two instantiations. In addition, we conducted the prospective analysis to identify the potential risks of accident response system of the Fukushima that were not reported in actual Fukushima accident. Conclusion: This study suggested that how the variability of the functions of system connected and contributed to the expansion of the accident. The FRAM can be used to reduce the risk of system-wide hazards through analyzing the combination of variability of system functions, identifying the potential risks related to safety. Application: The FRAM will be a systematic method of analysis for in-depth risk management.