Preliminary design and thermo-mechanical analysis of the ECRH equatorial launcher focusing mirror (M1) towards the CFETR

The Electron Cyclotron Resonance Heating (ECRH) Equatorial Launcher (EL) is under research towards the China Fusion Experimental Tokamak Reactor (CFETR). In the latest pre-research model, 6MW of electromagnetic waves would be guided to the plasma by two focusing mirrors (M1 & M2) and one front plate steering mirror (SM). Since the M1 will experience intense heat generation from ohmic dissipation and neutronic irradiation, a specific water-cooling structure has been designed for it to reduce the thermal deformation, allowing the M1 to experience less mechanical pressure during long pulses. The simulation demonstrates that water can efficiently dissipate -0.3 kW of neutronic heat and -30 kW of ohmic loss heat. As a result, the maximum deformation and equivalent stress are less than 0.4 mm and 160 MPa, respectively, which satisfactorily meets the system requirements.