Design status of JT-60SA cryostat and structual analysis of top lid

Nakamura, Shigetoshi; Shibama, Yusuke; Masaki, Kei; Sakasai, Akira

The JT-60SA project is to contribute to realization of fusion energy by supporting exploitation of ITER and by complementing ITER and engineering issues for DEMO reactors. A main component, providing vacuum insulation, radiation shield, and components' support, is cryostat. Cryostat split in two major segments; base and vessel. The base is under the manufacturing, and the vessel is still in designing. We present design status of entire cryostat and structural analysis of the top lid, which is final part to close the cryostat vessel. To achieve vacuum insulation of 10Pa each mechanical joints' flanges of cryostat segments are lightly welded as vacuum sealing. The normal load conditions consist of; atmospheric pressure, heat load and electromagnetic force. The top lid of the cryostat is also required of the sufficient integrity and the certain stiffness to protect the sealing weldment. We present the structural integrity clarified by stress evaluation and adequate reinforcements.