Bulky metallic structures are needed in the toroidal field (TF) superconducting magnets for fusion applications to withstand the large Lorentz forces acting on the winding. The pulsed coil operation during the plasma scenario and the fast current discharge or a plasma disruption in off-normal operating conditions cause magnetic field variations, inducing eddy currents in the TF structures. The...
The demonstration fusion power plant DEMO by EUROfusion Consortium has now entered its conceptual design phase. DEMO is intended to demonstrate the necessary technologies for controlling a very powerful plasma, generating electricity consistently, and a reliable maintenance of the plant itself. Consequently, the plant design is a challenge not only for its physics conditions, but also for its...
Several designs of Nb3Sn Cable-In-Conduit Conductors (CICCs) have been proposed so far for high-performance tokamak magnets. The Nb3Sn strands composing the conductors are submitted to mechanical stresses of electromagnetic (EM) and thermal origin, inducing local deformations and affecting the strands critical current carrying capability. Even though it is possible to test the conductors to...
The Comprehensive Research Facility for Fusion Technology（CRAFT）project is a key pre-research project of the China Fusion Engineering Test Reactor (CFTER) device in China. The manufacture of a full-size CFETR toroidal field（TF）coil is one of the key sub-topics of the CRAFT project, which is completed by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP). A hybrid...
This paper describes the design activities on the Toroidal Field (TF) conductor and coil of the DEMO Nuclear fusion power plant. As prototypes of future commercial tokamaks, DEMOs are expected to be able to produce cost-effective electrical power. In this view, an optimized design becomes a crucial aspect in the whole engineering design procedure. The 2018 baseline of DEMO reactor includes 16...
The Roadmap to Fusion Electricity draws on innovative experiments pivotal for the accomplishment of the European DEMO, i.e. the demonstration fusion power plant by the EUROfusion Consortium. At the end of the pre-conceptual design phase, the machine comprises three main magnetic systems: 6 poloidal field (PF) coils, 16 toroidal field (TF) coils and the central solenoid (CS), primary member of...
The electrical and physical properties of $\mathrm{Nb_3 Sn}$ strands are strongly dependent on the heat treatment during which tin diffuses into niobium by solid-state diffusion. During diffusion, $\mathrm{Nb_3 Sn}$ grains grow at the Nb/bronze interface. The shape and size of the grain depend on the temperature of the last step of the heat treatment, its duration and the size of the Nb...
One of the most actual problems of modern physics is the development of powerful radiation sources in the THz band. At the moment, the highest pulse and average power in the THz band are realized by the fast-wave devices – free-electron lasers and gyrotrons. The gyrotrons are vacuum electronics devices based on the stimulated cyclotron radiation of electrons moving along helical trajectories...
Paschen failures in ITER and W7-X superconducting coils at the acceptance tests have shown that it is highly desirable to lower the coil discharge voltage of the DEMO TF coils. Another benefit of lowering the discharge voltage might be the reduction of the number of coil feeders, i.e. connect in series the TF coils inside the cryostat, which is attractive for machine integration. For a given...
Superconducting magnets in fusion reactors are subjected to a huge electromagnetic force of >100 MN/m. The magnets have to be sustained with a structure with a strong body to avoid high stress and deformation. Extrapolating existing fusion experimental device constructed ever, the total weight of the magnet system, i.e., the magnet and support structure, of a commercial fusion reactor is...
Abstract-China Fusion Engineering Test Reactor (CFETR) is the next device in the roadmap for the realization of fusion energy in China, which aims to bridge the gaps between the fusion experimental reactor ITER and the demonstration reactor (DEMO).
The toroidal field (TF) coils play a major part in the tokamak, which provide the main magnetic field to confine the plasma, and one TF coil has...
The poloidal field coils (PF1 to PF6) of the proposed EUROfusion DEMO machine are to be operated in the pulsed mode. The heat is deposited in these coils due to field changes during a normal plasma cycle, due to field changes corresponding to a range of plasma control actions, due to nuclear heat load, etc. The PF2-PF5 coils winding packs (WP) are made up of the NbTi cable-in-conduit...
