Operation Experience of the Wendelstein 7-X High-Temperature Superconductor Current Leads

Abstract

The fusion device Wendelstein 7-X is a modular stellarator, which went into operation at the Greifswald branch of the Max-Planck-Institut fur Plasmaphysik in December 2015. The main component is the superconducting magnet system that consists of 50 nonplanar and 20 planar coils, 14 high-temperature superconductor (HTS) current leads (CLs), and more than 100 superconducting bus bars. The HTS CLs with a maximum current of 18.2 kA were constructed, tested, and delivered by the Karlsruhe Institute of Technology (KIT). In the first plasma physics campaign, the nonplanar coils were operated with a maximum current of 12.4 kA, whereas the planar coils were energized up to 4.9 kA. This paper describes the performance of the HTS CLs during plasma operation. A comparison to the acceptance test results performed after the construction of the CLs at KIT will be presented.