Ageing phenomena of components and structures and operational issues Research actions need to be undertaken to expand knowledge on ageing phenomena of components and structures important to safety and develop predictive or/and remediating tools or operational practices to support safe Long Term Operation of the existing nuclear fleet in line with the safety objective of the Nuclear Safety Directive. They may also contribute to increased safety features in the Gen III design where possible/appropriate. They should include research on human factor wherever relevant, and identify best practices and possibly contribute to standards’ development and safety upgrades related to Long Term Operation (LTO) of Gen II and/or Gen III. Experimental research and/or numerical simulation to produce data and increase knowledge to better grasp ageing phenomena and deterioration mechanisms of Nuclear Power Plants (NPPs) and /or research reactors or fuels. Further development of predictive methods (especially linking neutron fluence and materials’ ageing), standards and tools for accurate assessment of remnant safe life or potential risk of failure of components and structures having implications to the safety performance and/or development of remediating methods or tools. Increased understanding on operational and/or management issues having implications to safety performance. An action dedicated to concrete structures is highly encouraged.International cooperation in this area must be promoted in order to provide additional value and consensus. At least 5% of the total action budget must be dedicated to Education and Training activities for Ph.D. students, postdoctoral researchers and trainees supported through the action (see Conditions for the Call- Eligibility and admissibility conditions).The Commission considers that proposals requesting a contribution from the Euratom Programme up to EUR 4.0 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts. The European NPPs fleet is currently at the second half of its designed lifetime. At the same time, the Nuclear Safety Directive (Council Directive 2014/87/Euratom of 8 July 2014) brings the nuclear safety standards to a higher level. An intense research activity is on-going at industrial, national and European level, and needs to be pursued, on the ageing of critical components, systems and structures important to safety to provide inputs to the decision makers and assure safe Long Term Operation (LTO). Data development for increased knowledge and understanding of ageing phenomena; development/qualification of tools, systems and practices for the reduction of vulnerabilities of operating plants in particular for foreseen LTO regimes. This action would support standards development as well as compliance with the amended Nuclear Safety Directive resulting so in reinforcement of the safety features of the Generation II and III nuclear reactors.