DEVELOPMENT OF A DIRECT INSULATION LAYER FOR A SELF-COOLED LIQUID-METAL FUSION-REACTOR BLANKET

The magneto-hydrodynamic (MHD) pressure drop in a self-cooled liquid m etal fusion reactor blanket can be significantly reduced by means of e lectrical insulation of the flowing liquid metal against the structura l material. Since alumina is chemically stable against Pb-17Li at up t o 500 degrees C, direct insulation of MANET steel was performed by alu minizing the steel, using a hot-dip process followed by high-temperatu re oxidation. The aluminide layer formed in this process was insulatin g and stable against corrosion in flowing Pb-17Li alloy at 450 degrees C for 10 000 h. Several temperature changes during the corrosion test s did not cause any damage of the insulating layers. Thus, the process of hot-dip aluminizing followed by optimized oxidation at high temper ature can provide a direct insulation layer to suppress MHD effects.