THE JT-60SA CRYOPLANT CURRENT DESIGN STATUS

Abstract

In the framework of the ITER Broader Approach, CEA is carrying out the procurement of the Cryogenic System to the JA-EU Satellite Tokamak JT-60SA, which should be operated in Japan at JAEA, Naka in 2014. According to the Conceptual Design Report, JT-60SA is to operate for periods of at least 6 months per year, with major shutdown periods in between for maintenance and further installation upgrades. For this operation scenario, the cryoplant and the cryodistribution have to cope with different heat loads which depend on the different JT-60SA operating states. The cryoplant consists of one 4.5 K refrigerator and one 80 K helium loop, each pre-cooled by LN2. These cryogenic subsystems have to operate simultaneously in order to remove the heat loads from the superconducting magnets, 80 K shields and the divertor cryopumps.The first part of this study is based on the Process Flow Diagram (PFD) and presents the current design status of the JT-60SA cryogenic system. The second part is dedicated to the analysis of the cryoplant normal operation modes including the regeneration mode of the divertor cryopumps.Thanks to this analysis, the architecture of the present PFD is proposed in order to match the technical specifications of the cryoplant with the JT-60SA operation requirements.