The current leads of the Wendelstein 7-X superconducting magnet system

摘要

The stellarator fusion experiment Wendelstein 7-X (W7-X) is presently under assembly at the Greifswald branch of the Max Planck Institute for Plasma Physics (IPP), Germany. The W7-X superconducting magnet system basically consists of 50 non planar and 20 planar coils including the interconnecting bus bars, and the support structure. The seven electrical circuits with ten coils each in series, are supplied by 14 current leads (CL) operating between the cryogenic and ambient temperature environments. A special feature of these feed troughs is their upside-down orientation to save space in the vicinity of the machine. Basic electrical CL requirements are maximal steady state currents of 18.2 kA and voltage strengths of 13 kV to ground. A W7-X current lead consists of a copper conductor which also acts as a heat exchanger at the warm end side, in its continuation of a high temperature superconductor part, and at the cold end side of a copper bar with integrated Nb