Development of Risk Criteria for an Integrated Nuclear Safety and Security Potential Facility
Risk Index (PFRI)

Risk assessment is used to determine the likelihood and consequences of harmful events occurring at a nuclear facility. Regardless of the cause of the event, the goals of nuclear safety and nuclear security are the same: to protect people, property, society, and the environment from the harmful effects of ionizing radiation. Although security issues are receiving more attention than in the past, the security regime of nuclear industry is still far less developed than the safety regime. For this reason, the Potential Facility Risk Index (PFRI) was developed to evaluate and quantify the security risks associated with nuclear facilities. The PFRI assesses the nuclear security risk of nuclear facilities by developing scenarios and carrying out quantitative assessments that include threat, vulnerability, and consequence analysis. Nevertheless, the goal of PFRI is to cover not only security, but the overall risk of nuclear facilities. In order to achieve this, traditional safety probabilistic risk assessment (PRA) techniques have been added to coordinate risk units of both the PFRI and other safety risk assessment methods. While assessment is important, valid indicators of safety and security risk must also be established for the decision-making process. To this end, the indicator should clearly present the risk index of the facility by comparing the evaluated risk with convincing risk criteria. Therefore, this study investigated and compared accident risk standards established by various industries to devise risk criteria for nuclear facilities. This allowed for the establishment of risk determination criteria and risk levels for PFRI, enabling integration of the overall safety and security risk of nuclear facilities. These criteria were also used to calculate PFRI examples based on available information regarding safety PRA results from other nuclear facilities. The development of an integrated risk index for nuclear facilities in this study is expected to aid in the rational and quantitative assessment of overall facility risk.