Quench protection for the superconducting magnet system of WENDELSTEIN 7-X

WENDELSTEIN 7-X, a superconducting fusion experiment, is presently under construction at the Greifswald branch of the Max-Planck-Institut fur Plasmaphysik (IPP), Germany. The magnetic confinement of the plasma is achieved by 70 coils. In case of a rapid shutdown (e.g., caused by a quench) a very reliable protection system has to reduce the current in all coils within seconds. Different concepts applying linear and nonlinear resistors, which operate at room temperature or at 80 K, were studied. To switch the current electronic and mechanical breakers were considered. The paper presents the concepts studied and describes in detail the selected solution.