Development of a Reference Book on Common Cause Failures in German Nuclear Power Plants

GRS is analysing reportable events from nuclear power plants (NPPs) in Germany for more than 40 years. This also includes the consideration of common cause failures (CCFs). For this purpose, GRS has created a database contain-ing CCF events. Amongst others, this database has been applied to estimate CCF probabilities as input parameters for probabilistic safety analyses (PSA).

In the frame of a recent research and development project, the collected data are being used in their entirety for a generic analysis of CCF of components in German NPPs. This research activity aims at providing a comprehensive reference book with respect to CCF. For this purpose, the events recorded in the database will be sorted by different categories, such as "component affected" or "characteristic aspect". In this context, a characteristic aspect is a key-word-such as a description of the cause of the event, for example "corrosion" or "incorrect or missing specifica-tions." Commonalities of the events will be identified and described.

This paper presents an overview of the database contents, a brief description of the planned analysis and the method-ology applied as well as first results.

Keywords: Common cause failure, CCF, Generic analysis, Nuclear power plant, Operating experience, Systematic fault.

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