Feasibility of Utilizing Tungsten Rod for Fusion Reactor Divertor

The thermal and fatigue properties and the irradiation hardening of the potassium (K) doped tungsten (W) rods (20 mm in diameter) developed for fusion reactor divertor applications were investigated, and they were compared with the conventional hot-rolled W plates, which were previously reported. A part of the fatigue life of conventional hot-rolled W plate was newly obtained in this work. The K-doped W rod showed a few percent lower thermal conductivity than the conventional hot-rolled W plates. However, those values may meet the requirements of the ITER divertor application. The fatigue life at 500°C of the K-doped W rod was similar to the pure W plates at higher strain, whereas longer fatigue life of the K-doped W rod was observed at lower strain. The recrystallized K-doped W rod showed longer fatigue life at 500°C than the recrystallized pure W plates. The irradiation hardening level of the K-doped W rod was similar to the pure W plate after the irradiation up to 3 dpa at 500°C. Based on these evaluations of this work, the K-doped W rod in this work has similar or better properties than the conventional hot-rolled W plates under these particular test conditions though further evaluation and producing larger rods are desirable for the actual design and fabrication of the divertor.