Design of the prototype conductors for the Fusion Experimental Reactor

The prototype conductors of the toroidal coil for the Fusion Experimental Reactor have been investigated. Specifications of the conductor are as follows: forced flow cooling; rated current of 30 kA at 12 T and 4.2 K; margin of critical current of 2; current density in winding of 30-40 A/mm²; inlet helium at 4.2 K and 4-10 bar; and minimum bending radius of 1.5 m. Three types of conductors were considered as candidates: a test module coil of FF type (hollow cooling type using test module coil Nb₃Sn conductor techniques); preformed armor type; and advanced disk type. Detailed design parameters and analysis results are given for the three candidate conductors