1 431 Test Results of ITER Conductors in the SULTAN Facility

Starting March 2007, over 60 ITER cable-in-conduit conductors (CICC) have been tested in the SULTAN test facility in Villigen, Switzerland, including TF, CS, PF, CC and busbar samples. The test reproduces the actual operating conditions in the ITER coils, except for the hoop load and the CS peak field. Depending on the stage of the procurement, the SULTAN samples are categorized into Design Verification, Supplier Qualification (Phase I), Process Qualification (Phase II), Pre-Production and Series Production. The number of remaining samples to be tested during the ITER construction phase is about 40. For the NbTi CICC, the results confirm the prediction from the strand data, which are made taking the peak field over the conductor cross section as operating field. At low current density, where the n-index of the transition is measurable, the NbTi CICC and the NbTi strand have the same n-index. All the NbTi samples passed the supplier qualification phase. For the Nb3Sn CICC, the performance prediction is not straightforward because of the irreversible degradation caused by filament damage occurring during cyclic loading. At the first run of the test campaign, the performance of all the Nb3Sn samples largely meets the requirement for all the tested samples. Contrary to the NbTi CICC case, the n-index of the transition is substantially lower than in the strands, providing evidence of irreversible degradation. The performance loss upon load cycles and thermal cycles has a broad range among the various conductor samples. For the CS conductors, the final phase of the supplier qualification starts in November 2012.