Analysis of performance for the EAST W/Cu divertor targets under high power H mode operation*

During the operation mode, the divertor target withstands complex time-evolution head loads combination of steady state ＞10MW/m2 and (ELMs, VDE) transient ~GW/m2, which would result in crack initiation / propagation or thermal fatigue damage accumulation and even failure in the tungsten surface and the interface between different materials. The mechanism of thermal fatigue damage initiation and propagation in W/Cu divertor target is necessarily further studied carefully. Based on the EAST operation capability of ITER-like high power H mode, the 3D heat loads on divertor target was analyzed by numerical simulation with PFCFlux and diagnostics on EAST. Then, with the elastic-plasic / mechanical facture finite element analysis technology and the theory of Linear fatigue damage accumulation, the mechanism of crack initiation and propagation will be investigated for the W/Cu divertor target. The conclusion could offer a pertinent guide to the next-step high-power long-pulse operation in EAST and other future fusion power reactors.