Optimization of W/Cu monoblock mock-up with FGM interlayer for CFETR devertor targets

Thanks to its excellent heat removal capability, good performance under high heat flux (HHF) test and higher critical heat flux (CHF) value, the water cooled monoblock type plasma facing component (PFC) will be the optimal choice for divertor targets of CFETR and future fusion reactor. The conventional ITER-like W/Cu monoblock PFC employs a soft Cu interlayer to relax thermal stress that has deteriorative irradiation effects of swelling and embrittlement by transmutation and would undergo plastic fatigue under HHF loads. To solve these issues, W/Cu monoblock with functional graded material (FGM) interlayer is designed for CFETR and future fusion reactor. The two parameters that are the number and thickness of the FGM layers are optimized via thermal and stress simulation by finite element method. The simulation result shows that FGM interlayer plays an important role in alleviating stress. And it is deduced that the optimized number and thickness of the FGM layers are 3 layers and 0.3mm of each layer, respectively.