Overview of the design approach and prioritization of R&D activities towards an EU DEMO

•An important objective of the EU fusion roadmap Horizon 2020 is to lay the foundation of a DEMO Fusion Power Reactor to follow ITER.•This paper describes the progress of the DEMO design and R&D activities in Europe in the EUROfusion Consortium.•Focus is on a systems engineering/design integration approach to identify technology & physics R&D requirements and address design challenges.•Preliminary design choices/sensitivity studies to explore the design space and identify/select attractive design points are described.•Initial results of work conducted by distributed project teams involving EU labs, universities, and industries in Europe are presented.

This paper describes the progress of the DEMO design and R&D activities in Europe. The focus is on a systems engineering and design integration approach, which is recognized to be essential from an early stage to identify and address the engineering and operational challenges, and the requirements for technology and physics R&D. We present some of the preliminary design choices/sensitivity studies to explore and narrow down the design space and identify/select attractive design points. We also discuss some of the initial results of work being executed in the EUROfusion Consortium by a geographically distributed project team involving many EU laboratories, universities, and industries in Europe.