ICDE-Results on Complete Common Cause Failures in the Light of Results Obtained with the POS Model

摘要

Since April 1998, the OECD Nuclear Energy Agency (NEA) is operating the International Common Cause Data Exchange (ICDE) project. For a large number of about 1000 ICDE events the fractions of complete CCFs, which are in most cases of great relevance to bottom line PSA results, have been analyzed as a function of the degree of redundancy. From the point of view of quantitative CCF modelling, the development of an approach to reflect the empirically available complete CCF fractions in a CCF model application represents a challenging task.These components are operated under different conditions and technical specifications. Therefore, an approach is chosen which is based on low information distributions of the model parameters to account for the large variation throughout the component populations. The Process Oriented Simulation Model (POS) has been selected to carry out an analysis of complete CCFs. A more than reasonable consistency has been achieved between the model results and the observed results. Moreover, with these sets of distributions as input generic applications of the POS-model become possible. To underline this, generic P-factors are calculated as an example and compared to generic P-factors presently used in the design of advanced reactors.