Development of carbon based plasma facing components for steady state operation of the fusion devices in China

In recent years, a series of multi-element doped graphite materials has been developed for PFC (plasma facing components) in China. Detailed investigation of the composition and full characterization of the microstructure of the doped graphite were carried out in the last several years and are now still in progress. These research activities were mainly concentrated on multi-element (B, Si, Ti) doped graphite and thick gradient SiC coatings. Investigations on the applicability of doped graphite as PFC under high heat flux, and further evaluation under HT-7 limiter plasma irradiation have been carefully investigated. From a 0.3 m² poloidal limiter to a 1.2 m² new belt limiter plus two poloidal limiters with actively water-cooled, this changes to the new carbon limiter in the HT-7 device turned out to be very successful. The plasma performance has been significantly improved and the longest discharge duration has been more than 60 s. These results have demonstrated that new carbon armoured PFCs will be an attractive choice making them competitive with other candidate PFC for the first wall of steady state fusion devices.