Open Issues Associated With Passive Safety Systems Reliability Assessment

The efforts conducted so far to deal with and evaluate the reliability of passive safety systems (as the thermal-hydraulic passive systems), being implemented in advanced water cooled reactor designs, has aroused an amount of open issues. They should be addressed and conveniently worked out, since it is the major goal of the international community (e.g IAEA) to strive to harmonize the different approaches and to reach a common consensus, in order to add credit to the underlying models and the eventual outcoming reliability figures. The main open points are presented and discussed and a viable path towards the implementation of the research efforts is delineated as well.