Ageing PSA as a support for effective ageing management

Because of the growing operational age of nuclear power plants, the ageing management of structures, systems and components used in these plants is gaining an important role. Technical systems are subject to timedependent and operationally caused ageing phenomena with modifications of originally given characteristics and, thus, of relevance in terms of safety. Especially physical ageing is of importance. Therefore, a comprehensive ageing management is required. In the context of an integrated safety management it has to be shown how to integrate the safety related issues of ageing into probabilistic safety assessment (PSA). In particular the question is to be answered whether the effort for the execution of an ageing PSA is justified, in particular if the safety significant effects of ageing can be identified and quantitatively estimated. Method for prioritization of the components in the nuclear power plant considering implication of their ageing on safety of the nuclear power plant is presented. On the basis of an actual report on ageing management in German nuclear power plants and a literature survey, this paper tries to estimate the necessity and value for the introduction of an ageing PSA in Germany.