Conductor jacket development to meet the mechanical requirements of the ITER central solenoid coils

When energized, the ITER central solenoid (CS) coils experience large pulsed electromagnetic forces translating into a combination of tensile hoop load in the toroidal direction and transverse vertical compression to be resisted by the conductor jacket itself. A key parameter for the coil design is fatigue behaviour (60 000 cycles) of the CS conductor jacket. The mechanical requirements on the CS conductor jacket are derived from the mechanical analyses performed on the CS stack assembly. A prototype production of the two considered candidate materials, 316LN and JK2LB, a specially developed high Mn-bearing austenitic stainless steel, has been achieved in industry. Manufacturing specifications and first results of production controls are presented.