Structural materials for DEMO: The EU development, strategy, testing and modelling

DEMO in-vessel materials will be exposed to high neutron flux and high fluence, creating displacement cascades and transmutation products. This results in changes of the microstructure leading to degradation of mechanical and physical properties. per describes the R&D performed in the EU for the most promising structural materials with focus on EUROFER. Recently obtained results from mechanical testing as well as modelling will be presented and unresolved material issues on the path to DEMO will be addressed. The approach for an integrated program making use of existing material irradiation facilities, future devices like IFMIF and multi-scale modelling will be discussed.