Study on creep-fatigue of heat sink in W/CuCrZr divertor target based on a new approach to creep life

Abstract

Abstract Reliability and security of the fusion device are severely affected by the failure of the divertor. It is necessary to have a reliable life prediction for heat sink in W/CuCrZr divertor target, especially during long-term high heat flux operation in future fusion devices in which the high temperature creep accelerates its fatigue failure. In this study, a new approach to creep life was applied to creep-fatigue damage accumulation model for CuCrZr heat sink. It is proved that the results of new method for CuCrZr creep life calculation is more consistent with the experimental results than the previous empirical formula. Then the temperature and stress/strain results were calculated for two types of ITER-like monoblock using thermal–mechanical analysis which shows that high temperature creep could not occur on EAST divertor heat sink of current operating conditions. Based on creep-fatigue damage accumulation model, the predicted life of monoblock for DEMO divertor are given under different operating mode respectively. The model provides theoretical basis and guidance for the divertor engineering design of future fusion reactor like CFETR and DEMO in which the high temperature creep in heat sink must be taken into account due to long-term operation.