Design, qualification & manufacture of ITER gravity supports

Abstract

As one of the key components to support all the magnet coils, the GS faces engineering challenge to its operational safety throughout the design, qualification and manufacturing process as a result of extreme loading condition. The structural safety of GS was confirmed by both the FEM analysis and the semi-prototype engineering test after a long time of design, qualification, manufacture and assembly. Welding the cooling pipe to the flexible plate without obvious deformation as well as tightening uniformly and precisely all the tie rods to clamp the plates were carried out successfully during manufacturing. The result of final vacuum leakage test indicates that the GS can not only meet the ITER vacuum requirement but also have no slow out-gassing. The first set of GS which has passed the ITER acceptance test is to be delivered to ITER construction site soon.

Failure analysis of a heavy gauge fastener of the ITER toroidal field gravity support system

“…They will sustain 11,000 tonnes of dead weight while having sufficient compliance to adapt to the movement of the coils in the different phases of cooldown. In operation, they will be exposed to large electromagnetic forces and possible seismic loads [1]. The bottom of TFGS is fixed to the cryostat base through 26 high strength fasteners, namely heavy gauge M60 and M85 threaded bolts issued from forged rods of UNS N07718 (also known as Inconel® 718).…”