Ageing management at nuclear power plants should be proactive so that to timely detect the ageing degradations, and propose corrective actions to prevent structures, systems and components important to safety from ageing related faults. In order to mange the effect of ageing effectively, there are various plant programmes available which provide guidance on ageing management of active and passive components. Passive components are subject to ageing management review in order to identify ageing related degradations for given material, environment, stressors and operating loads. A comprehensive ageing management re-view is also required either for license renewal [1] or periodic safety review [2] of nuclear power plants. Active components which perform their intended functions with moving parts or with a change in con-figuration are subject to preventive maintenance and replacement based on qualified life or specified time period; therefore the ageing management review is typically not performed. Instead, the plant maintenance programmes are established that should be able to detect timely the component degradation before it fails. The plant maintenance and ageing management programmes aim at early detection of component ageing degradations; in an ideal case, there should not be that many ageing related event reports. Despite the plant efforts to handle the ageing of structures and components important to safety, a review of operating experience worldwide shows that there is still number of events reported that were caused by ageing related faults of systems and components to perform their intended functions. This Summary Report presents the results of a comprehensive study [3] performed by the European Clearinghouse on Operating Experience Feedback of NPP with the support of IRSN (Institut de Sûreté Nucléaire et de Radioprotection) and GRS (Gesellschaft für Anlagen und Reaktorsicherheit mbH). This study addresses physical ageing mechanisms of Structures, Systems, and Components (SSC) such as wear, tear, fatigue, corrosion, oxidation, loss of material strength, loss of insulation resistance, loss of elasticity (or other potentially significant ageing mechanism) are the main focus of this study. Obsolescence, although it is important issue too, has currently not been included in this report. It may be addressed as specific subject in some future Clearinghouse Topical studies. ; JRC.F.5-Nuclear Reactor Safety Assessment