Mechanical properties of the prototype cable-in-conduit conductors for NET

Extensive mechanical tests on full-size and subsize cables, with and without steel jacket, at liquid nitrogen and liquid helium temperature have been carried out on the three prototype CIC (cable-in-conduit) conductors manufactured for NET (Next European Tokamaks). The measurements include tensile tests from the basis strand to the full size conductor, compression tests of cable and jacket, bending test, friction test between cable and jacket, and transversal and axial cyclic loading with hysteresis measurements. It is suggested that hard copper wires can be expected to provide a good basis for establishing the cabling process for a multistrand superconductor. Heating due to mechanical cycling of cabling is not significant compared to typical AC loss effects. Overall tension of the superconducting strands should be avoided as irreversible mechanical effects seem to occur at low strains (0.3%)