New Risk Assessment Method for a Reprocessing Plant: Quantitative Safety Assessment

In a reprocessing plant, the various and many accidents identified related to mechanical processes, chemical processes, and storage facilities have to be assessed to know the total risk of the plant. To assess the individual risks of so many potential accidents efficiently and effectively, we have developed a simplified quantitative method called quantitative safety assessment (QSA), based on our experience in probabilistic risk assessment (PRA) for the Rokkasho Reprocessing Plant and with reference to the integrated safety analysis used in the United States for fuel cycle facilities. Our method not only includes such PRA features as quantifiability of the results and comparability of risk importance of the contributors to accident sequences but also offers the new features of simplified presentation and easy traceability. The designation of important safety structures, systems, components, and personnel activities is thus facilitated through the use of the results of this method. In this paper, the deployment of the QSA method is demonstrated using an example of a criticality accident in a plutonium partition process.