Fusion Science and Technology / Volume 50 / Number 4 / November 2006 / Pages 546-550
In the next generation of fusion device in China, e.g., the Experimental Advanced Superconducting Tokamak (EAST), the divertor target will be exposed to high heat loads up to 5 MW/m2 for about 1000 s. An actively water-cooled target plate element with flat tungsten tile armored on CuCrZr heat sink was designed for EAST. A two-dimensional finite element method (FEM) code was used to analyze its thermal and mechanical properties under high heat flux of 10 MW/m2 for the selection of an appropriate cross section. To meet the integrated requirements of temperature and stress in the target element, twisted tapes have to be inserted into the cooling channels to strengthen the heat transfer efficiency, and a tungsten armor thickness of 4 mm and a distance of 2 mm from the interface to the vertex of the cooling channel were ultimately selected. The thermal and mechanical properties of two kinds of tungsten armor (sintered and plasma sprayed) were also analyzed and discussed in the FEM calculations. The designed structure can be used under the 5 MW/m2 heat load expected for normal operation of EAST device, but it would suffer from cracks/failure danger under higher heat load, up to 10 MW/m2.