Evaluation of thermal structural behavior of divertor under ELM

In this study, a YAG laser was used to simulate the transient heat load like ELM for the tungsten target, and the experiment results were compared with the analysis results by using finite element method. Average of total heat flux, ELM energy flux, and pulse width of ELM was considered as parameters in the analysis. Based on the results the thermal structural behavior of tungsten target under ELM was evaluated. When approximately 0.25 MJ/m² of ELM energy flux was applied, crack, and plastic deformation occurred at the tungsten surface even though recrystallization was not confirmed. It implied that the tungsten target could be damaged by thermal stress even at below 0.5 MJ/m². In addition the crack propagation under ELM was also investigated in this study.