Advances on the Design of Demountable Toroidal Field Coils With REBCO Superconductors for an ARIES-I Class Fusion Reactor

The recent development of REBCO superconducting tapes, cabling methods and joint concepts could be a revolutionary development for magnetic fusion. REBCO has better performance at high magnetic fields than traditional low temperature superconductors (LTS), and can be operated at a higher temperature than LTS for reduced thermodynamic cost of cooling. Use of REBCO superconductors in the magnet systems of tokamaks allows building demountable toroidal field (TF) coils, greatly simplifying reactor construction and maintenance. A demountable 20 T TF coil system with REBCO superconductors for an Aries-I class reactor has been conceptually designed. The coils have two elongated areas, one in the top of the coil and another in the outer midplane, where the mechanical and electrical demountable joints are located. The mechanical joints are closer to the inner part of the coil to reduce displacements and loads in the electrical joints. The electrical joints are composed of REBCO superconductor covered with copper for mechanical protection. The mechanical joints are composed by dovetail structures in the top, and are supported by bolts in the outer midplane.