The Engineering Design of EAST Lower Advanced Divertor

In the next 3-4 years, the objective of EAST Tokamak is to achieve longer pulse more than 400s H-mode plasma. So the divertor system of EAST shall accommodate the high heat flux up to 10MW/m² on the divertor target. The upper divertor now is tungsten divertor with mono-blocks structure. But the lower divertor of EAST is still carbon divertor, which can only endure heat flux up to 2MW/m² . So the lower divertor shall be updated to fit such heat load. To get snowflake and others advanced divertor shapes, three divertor coils are configured under the lower divertor. The whole lower divertor is divided into 48 modules. Each module is composed of an inner target plate, a Dome, an outer horizontal target plate and an outer vertical baffle plate. To minimize the total mass flow of the cooling system, all these plate are serially connected. To optimize the heat removal capacity of the cooling structure and cooling pipe system of the lower divertor, several types of cooling structures and cooling water distribution systems are considered. Through thermal analysis, fluid analysis and results comparison, the potential final cooling system is determined.