European benchmark exercise on common cause failure analysis

The Joint Research Centre of the CEC has programmed a series of benchmark exercises in order to assess the state of the art in reliability assessment methodology, to assess the uncertainties involved and to eventually arrive at consensus procedures for carrying out analysis. The Common Cause Failure Reliability Benchmark Exercise is the second in the series and deals with the problem of identifying, modelling and quantifying dependent failures. On the basis of a real reference plant (Grohnde reactor, auxiliary feedwater) and system, a common set of problems was defined and analysed by ten different teams. The results were then compared and discussed and a certain number of important conclusions could be formulated. The paper describes how the CCF-RBE was organised, which results were obtained and discusses the lessons that could be learned from it. (orig./HSCH)