Quality of Supplied Components - Impact to Nuclear Safety

This paper presents the essential results of a study performed by the European Clearinghouse on Operational Experience aiming to analyze the impact of inappropriate components supplied to Nuclear Power Plants (NPPs) on safety. Study has been performed by means of extracting, systematizing and analyzing of adequate operational experience related information from event reports stored in relevant data bases. The methodology of the study includes identifying, highlighting and examining of circumstances, precursors, causes and safety significance of said events, as well as of most important corrective actions, lessons learned and recommendations. All production stages (including design, manufacturing, storage, and transportation) are taken into account in our study as well as the main defence lines of the licensee designed to prevent penetration of substandard components. The major contributors and causes of the reported events are deficiencies in design and manufacturing causing 42% and 32% of events respectively. We highlighted that the most frequently failing groups were mechanical and electrical components and among them mostly valves, seals, circuit breakers and relays. The overwhelming majority of the supply-related events seems to be caused by the same group of common fundamental causes: inadequate quality/safety culture and deficiencies or ineffectiveness of management systems, of quality management or of quality assurance. By scrutinizing the causes and lessons learned from the events and looking beyond the component-specific or condition-specific ones, we formulated some generically applicable recommendations.JRC.F.5-Safety of present nuclear reactor