Ageing management (AM) programmes have been launched in many countries. The situation in Germany concerning long term integrity of safety relevant NPP-systems and components is determined by the requirements stated in regulations and codes. They contain basic requirements for continuous precaution measures according to the current state-of-the-art starting already with the plant commissioning. This included demands for redundant safety and for surveillance measures. A continuous adjustment related to the requirements of the respective state-of-the-art is provided by E.ON Kernkraft and submitted to the responsible safety authority to demonstrate an appropriate integrity status of the safety relevant systems. It is understood that the subject "Ageing Management" is comprehensively covered by the entirety of the different precaution and maintenance measures and regulations already established. The assessment of relevant long-term ageing phenomena for mechanical, electrical and structural components depends on the graduated safety relevance of a component associated with "proactive" measures or "reactive" measures. The assignment of such safety requirements to corresponding measurements for relevant components is arranged in three groups of high, medium and low safety relevance. For components of group 1 with a high safety relevance a so called integrity concept is applied, i.e. causes and consequences of operational loadings are monitored and redundant measures such as non destructive examination and inspections are performed whereas the component must maintain a demanded quality status in operation. In group 2 active and passive components are assembled which are redundant and of medium safety relevance. A single failure of a component of this group is allowed. The safety targets are integrity, functionality and leak tightness. These targets are met by applying preventive maintenance and functional testing. The components of lowest safety relevance are found in group 3 with failure related maintenance. This paper presents the existing concept in E.ON Kernkraft and its sound application to ageing management issues by focussing on group 2 components such as safety relevant valves. It is demonstrated how the maintenance concept of safety relevant valves is supported by a valve diagnostic system accompanied by an applied procedure to assess the measured results with respect to the required functionality and ageing phenomena. Furthermore this concept has been developed to optimize the existing preventive maintenance of the safety relevant valves by implementing condition oriented aspects derived from the diagnostic results. The main issue of this maintenance concept is to demonstrate the high level of the secured function, reliability and performance of the safety relevant valves within an integrated ageing management. Additionally it offers improvements of all preventive maintenance issues as maintenance periods and the component related volume, spare parts management and costs.
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