Test of PF1 Coil Electrical Joint

Abstract

The PF1 coil manufactured in the Russian Federation is one of the six poloidal field (PF) coils of the ITER electromagnetic system. The PF1 winding represents a stack of eight double pancakes (DPs). Each DP is wound from niobium–titanium “cable-in-conduit” conductors using the “two in hand” technique. The PF1 unidirectional winding is provided by connecting the ends of DPs into a single electric circuit by “shaking hands” low-resistance joints. An acceptance criterion for manufactured joints is an active resistance of less than 5 nΩ in the range of PF1 operating temperatures and applied magnetic fields. The initial joint design was updated on the basis of deviation requests of the ITER Organization. As a result, the previously developed techniques and tools were upgraded. To verify the modifications made, the preliminary joint sample was manufactured and tested in the NIIEFA test facility. Despite the limited current (up to 20 kA) and magnetic field, the results of the NIIEFA test verified the possibility of meeting the acceptance criterion and allowed us to start the manufacturing of the qualification joint sample. The final electrical test was performed in the “SULTAN” test facility of the Swiss Plasma Center (Switzerland). The test results are presented in this paper.