Materials research for Generation-IV reactors Whilst the EU nuclear materials research community has significant experience and extensive knowledge of materials behaviour under conditions typical for Generation-IV reactor concepts, there are still some areas where further research and innovation is needed to reach technological maturity. This applies in particular to changes in properties of materials and joints under fast neutron irradiation and/or high temperature of the coolant, as well as to the compatibility between structural materials, the coolant and advanced fuels. This action should include the refinement of physical models and/or modelling-oriented experiments aimed at the validation of models of microstructural change and the resulting effects on material properties, as well as advanced micro-structural characterisation techniques. This research and innovation could also include the development, testing and qualification of mitigation strategies involving, for example, the development of suitable surface engineering concepts for current known material deficiencies.The Commission considers that proposals requesting a contribution from Euratom of between EUR 2 and 5 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts. Proposals for topics NFRP 1 to 5 will be ranked in a single ranking list. As highlighted in the Joint Programme on Nuclear Materials (JPNM) developed by the EERA[[European Energy Research Alliance]], materials research and innovation is at the cornerstone of many technological developments, notably in the nuclear field, where technical qualification and certification are subject to stringent safety criteria. It is therefore of paramount interest for Euratom to support research and innovation in this area, notably for resolving the key remaining issues regarding structural and fuel materials to be used in Generation-IV reactor concepts under consideration in the EU. This action aims at significant progress regarding the predictive capability of changes in material properties and behaviour and subsequent refinement of Generation-IV reactor design codes. This will help to overcome the bottlenecks in the certification of materials and hence in the development of safety demonstration for Generation-IV reactor technologies. In addition, it is expected that progress achieved in Generation IV material related technology could contribute to safety improvements in other nuclear energy systems and components.