CURRENT STATUS OF THE COMPONENT FAILURE RATES ESTIMATION WORK BASED ON THE REPROCESSING PLANT MAINTENANCE DATA

摘要

In usual probabilistic safety assessment (PSA) studies for a reprocessing plant, most of the data on component failure rates are extracted from those of nuclear power plants (NPPs), chemical plants and general industrial components in published literatures because available data on component failure rates of reprocessing plants are extremely limited. Therefore, it is expected to prepare component failure rates based on the maintenance data of an actual reprocessing plant. On the other hand, the Tokai Reprocessing Plant (TRP) has been operating over 30 years since 1977. Maintenance records of plant components have been accumulated and compiled in the Tokai Reprocessing Plant Maintenance Support System (TORMASS). The TORMASS is an effective source to pick up component failure information. From this viewpoint, a basic study to estimate component failure rates for a reprocessing plant has started in the Japan Atomic Energy Agency (JAEA) from 2005 using maintenance data of TRP because it is an only reprocessing plant having long operational experience in Japan. The study aims to contribute the development of reliable component failure rates which enhance the reliability of a reprocessing plant PSA. By the end of 2006, failure rates for 17 types of 392 components associated with the cooling function for the High Active Liquid Waste (HALW) storage process had been estimated. These estimation results were compared with the published failure data of nuclear power plants. This work was the first attempt in Japan to generate the component failure rates from an actual reprocessing plant maintenance data. This result is expected to contribute to building up generic database of component failure rates for a reprocessing plant in order to promote the utilization of risk information for reprocessing plants in Japan.