Structural analysis of the W7-X cryopump during the superconducting coil fast discharge event

The cryopump will be installed for the high power and long pulse operation up to 30 min of Wendelstein 7-X (W7-X). In total there are 10 independent and identical cryopumps, one cryopump for each of the 10 discrete divertor units. The cryopump is located along the pumping gap in the toroidal direction below the divertor target modules and close to the location where field lines hit the divertor target surface. Each pump has a design envelop of ∼400 mm diameter and ∼4 m length. During a fast discharge event of the W7-X superconducting coils, the changing magnetic field will induce eddy currents on the metallic cryopump components, especially on the low resistance copper parts. The combination of the eddy current and the background magnetic field will generate mechanical forces and moments on the cryopump structure. The electromagnetic analysis provided the eddy current and Lorentz force distribution as an input for the mechanical analysis. These analyses showed no possible resulting damages on the structure of the cryopump.