EU-DEMO design space exploration and design drivers

Once the high-level requirements for a fusion power plant are set, the expected performance of plant systems, including the plasma, must be defined and then the available design space for the plant can be explored in order to converge on a final overall plant operating point, setting the major plant parameters such as number of toroidal field (TF) coils, tokamak major radius, plant power flows etc. Such design space explorations are conducted using systems codes which contain simplified models for plant systems, and attempt to capture the interactions between them in order to balance performance trade-offs and enforce overall consistency. This paper summarizes the work carried out to identify the EU-DEMO baseline operating point and the underpinning assumptions about technology and physics performance. The major design choices are described and the principle drivers for the direction of conceptual development, resulting in the operating space for EU-DEMO, are identified. The final output of the systems code forms the basis for more detailed engineering and physics evaluation and design work.