Abstract
Abstract
Since April 1998, the OECD Nuclear Energy Agency (NEA) is operating the International Common Cause Data Exchange (ICDE) project. The objectives of this exchange comprise, to collect and analyze CCF events, to generate insights into root causes and derive preventing approaches, to strengthen experience feedback and, last but not least, to facilitate quantification. For a large number of about 1000ICDE events the fractions of complete CCFs have been displayed as a function of the degree of redundancy. Complete CCFs are relevant to PSA as in these cases the respective function fails and in many cases significant contributions to core damage can be expected. From the point of view of quantitative CCF modeling, the theoretical theoretical approach to of the empirically available complete CCF fractions represents a major challenge. The large number of events have been collected in the ICDE project for nine different types of components in nuclear power plants from ten different countries. Obviously, 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. The consistency between the theoretical approach – considering its simplicity – and the data observed is satisfactory.