Analysis of common cause failures

The aim of the work was to perform research and evaluation of available information. The description concerns both qualitative aspects and quantification of probability of residual common cause failures (CCFs); hence, the effect of those common causes that are not explicitly included in the probabilistic safety assessment (PSA) model is also considered. The issue of CCF description and modelling for a particular PSA study cannot be separated from the particular system modelling style applied. Therefore, an informative chapter was included explaining the style of modelling in a first level PSA study and the issue of inclusion of the various types of dependent failures in the PSA model. The chapter than follows deals with the mathematical models for determining the probability of a CCF. The next part focuses on the analysis of data from the operation of nuclear power plants. (P.A.)