Estimation of common cause failure parameters for diesel generators
J. Tirira, J.M. Lanore,
PSA2 meeting, Detroit, octobre 2002,
This paper presents a summary of some results concerning the feedback analysis of French Emergency diesel generator (EDG). The database of common cause failure for EDG has been updated. The data collected covers a period of 10 years. Several latent common cause failure (CCF) events counting in tens are identified. In fact, in this number of events collected, most are potential CCF. From events identified, 15% events are characterized as complete CCF. The database is organised following the structure proposed by “International Common Cause Data Exchange” (ICDE project). Events collected are analyzed by failure mode and degree of failure. Qualitative analysis of root causes, coupling factors and corrective actions are studied. The exercise of quantitative analysis is in progress for evaluating CCF parameters taking into account the average impact vector and the rate of the independent failures. The interest of the average impact vector approach is that it makes it possible to take into account a wide experience feedback, not limited to complete CCF but including also many events related to partial or potential CCF. It has to be noted that there are no finalized quantitative conclusions yet to be drawn and analysis is in progress for evaluating diesel CCF parameters. In fact, the numerical coding CCF representation of the events uses a part of subjective analysis, which requests a complete and detailed event examination.