Fabrication and test of hydraulic jacks for the application to divertor support system of Fusion Experimental Reactor

Two different types of hydraulic jacks, consisting of hydraulic piston and bellows were developed for an application to locking and lifting systems for divertor segments for the Fusion Experimental Reactor. For the lifting system where a minimum stroke of 170 mm was required, a telescopic-type hydraulic jack with a length of 300 mm was fabricated and tested under an operation pressure of 1 MPa. For the locking system, a hydraulic jack with a conical cotter was developed that worked at 6.5 MPa under a radial offset of 2 mm. These jacks satisfied their specifications without any leakage, failure, or abrasion. The performance of several hard facing materials for the cotter, including alumina and metal alloys, was also examined. The Colmonoy No. 5 or Stellite alloy No. 6 was found to be excellent as a hard facing material for the cotter