Assessment Studies and Manufacturing Trials for the Conductors of DEMO TF Coils

This paper reports the main outcomes of the 2013 design activities for the TF magnet of the European nuclear fusion reactor DEMO. Within the current project plan, the manufacture of full-size conductor prototypes during 2014, and their test during 2015, are foreseen, aimed at the assessment of the proposed CICC technologies. Industrial partners have thus been involved already at this early stage, and the preliminary cabling trials performed are illustrated here. As far as the coil design assessment is concerned, one of the main aspects to be investigated was the mechanical performance of the magnet, considering its large size and the high electro-magnetic forces involved. An overall 3D Finite Elements model of the coil has been set-up and mechanical stress analysis has been carried out for a selected instant of the plasma scenario, after computation of the electro-magnetic loads within a full 3D system model, including CS and PF coil contributions. The resulting loads have been mapped on the FEM model, making use of a novel meshindependent interpolator based on Radial Basis Functions. The results reported here highlight a quite high level of stress, close to the acceptance limits, in some regions of the steel casing. Further investigations and assessments are required, but the most critical areas are clearly identified.