Updates on Magnet Design For EU-DEMO Reactor: Optimization Studies on TF and CS Systems

In the framework of EU design activities for dimensioning the future fusion DEMOnstration reactor (DEMO), extensive analyses were conducted in EUROfusion context, aiming at ultimately defining the design of the DEMO magnets system. In this objective CEA (Commissariat à l'Énergie Atomique et aux Énergies Alternatives) proposes design for both Central Solenoid (CS) and Toroidal Field (TF) cryomagnetic systems. Considering the latest DEMO reactor baseline both systems were investigated using pre-dimensioning CEA tool MADMACS, with an outcome of several options for each of them. In a second step those designs were investigated with detailed analyses (electromagnetic, thermohydraulic, mechanic). In the paper a broad analysis of the CS design considering fatigue constraints is shown, together with recommendations considering flux target. The TF system considered is an ITER-like option with radial plates and the detailed electromagnetic analysis is exposed and discussed in comparison with former methods. The outcome is used for a thermohydraulic detailed static analysis and a mechanical analysis of TF winding pack is provided and discussed in terms of results but of method as well. Global considerations and recommendations will also be provided to give a first view on cryomagnetic system optimization with respect to cost merits related to both magnet systems.