Comparative analysis of copper alloys for the heat sink of plasma facing components in ITER

Due to their excellent thermal conductivity, copper alloys are the obvious choice for the heat sink of the high heat flux (HHF) components in ITER. In addition to thermal conductivity, other properties have to be taken into consideration for the final selection of the alloy system and of the specific grade. For comparison, the following parameters have been taken into account: tensile strength and ductility, fracture toughness, allowable strain for fatigue endurance of 104 cycles, thermal stress factor, and thermal conductivity. An assessment is made of the proposed copper alloys to be used in ITER, precipitation hardened copper alloys (CuCrZr, CuNiBe, CuNiCrSi) and dispersion hardened copper (CuAl25). The analysis shows that CuAl25 is the most reasonable choice for the HHF components of the primary wall due to heat resistance and satisfactory design allowable (strength, fatigue and fracture toughness), CuCrZr is proposed for the divertor where the fatigue and resistance to fracture are most critical. (orig.)