High heat flux limits of the fusion reactor water-cooled first wall

Abstract

The water-cooled WCLL blanket is one of the possible candidates for the blanket of the fusion power reactors. The plasma-facing first wall manufactured from the reduced-activation ferritic-martensitic steel Eurofer97 will be cooled with water at a typical pressurized water reactor (PWR) conditions. According to new estimates, the first wall will be exposed to peak heat fluxes up to 7 MW/m2 while the maximum operated temperature of Eurofer97 is set to 550 °C. The performed analysis shows the capability of the designed flat first wall concept to remove heat flux without exceeding the maximum Eurofer97 operating temperature only up to 0.75 MW/m2. Several heat transfer enhancement methods (turbulator promoters), structural modifications, and variations of parameters were analysed. The effects of particular modifications on the wall temperature were evaluated using thermo-hydraulic three-dimensional numerical simulation. The analysis shows the negligible effect of the turbulators. By the combination of the proposed modifications, the permitted heat flux was increased up to 1.69 MW/m2 only. The results indicate the necessity of the re-evaluation of the existing first wall concepts. Keywords: High heat flux, Thermal performance factors, Turbulator promoters, First wall, Cooling, CFD