Safety evaluation by use of living PSA and safety indicators - Current status and future development of models and tools within the Nordic project safety evaluation, NKS/SIK-1

The paper presents the preproject results and the early phase of the Nordic research project ''Safety Evaluation, NKS/SIK-1'' (1990-93). The subjects discussed are mainly problem investigation and identification of development areas for the living PSA part of the project. To make proper safety related decisions and evaluations, the development of the plant state should be carefully monitored and evaluated. The SIK-1 project is intended to define and demonstrate the practical use of living PSA and operational safety indicators for safety evaluation and for the identification of effective improvements in operational safety. In our view, a risk monitoring system, tailored and implemented for plant specific use by its user organizations, can monitor and evaluate the plant state more efficiently, and undesired events can be prevented. The overall status of PSA and the experience gained in performing and utilizing PSA studies are quite similar among all utilities in Sweden and Finland. A natural step is now to pass towards a living use of present Level 1 studies at the plants. A basic PSA model intended for living PSA purposes has to be modified and enhanced in several areas. With data and tool improvements it is further necessary to reach a state where all capabilities of a living PSA are fully explored and utilized. Collection and analysis of relevant operational experience and development of systematic methods for the early identification of degrading developments and deficiencies is considered to be essential for safety. (author). 13 refs, 1 fig., 2 tabs