Wenhai Guan

Feasibility of Utilizing Tungsten Rod for Fusion Reactor Divertor

Abstract 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.

Fatigue Properties of SiC/SiC Composites Under Various Loading Modes

Abstract Because fatigue resistance is one of the most important issues for the blanket structural materials of the fusion reactor, the fatigue damage formation processes of the advanced SiC/SiC composite (Tyranno SA 3rd/CVI-SiC composite with SiC/C multilayer interphase) for fusion reactor applications were investigated. The fatigue tests of the SiC/SiC composite were successfully performed up to 105 cycles with no significant technical issues by using a small specimen test technique developed under the IFMIF/EVEDA. Based on the evaluation of the modulus change during the fatigue tests, the tensile loading was clarified to be a dominant factor for the degradation of the SiC/SiC composite.

Effect of Non-Uniform Deformation on Low Cycle Fatigue Properties of Electron Beam Weld Joint of F82H Steel

Abstract To improve the fatigue properties evaluation of the joint region of the fusion reactor blanket, the effect of the non-uniform distribution of the microstructure and strength on the fatigue properties of the electron beam weld joint of the F82H steel was investigated by the fatigue test and the numerical simulation of the deformation under the test. The fatigue life of the joint was approximately 10–20 % of that of the base metal. The fracture under the fatigue test occurred around the over-tempered heat affected zone (the region with the lowest hardness). One of the reasons of the shorter fatigue life of the joint could be the higher crack growth rate induced by the peak strain around the over-tempered heat affected zone due to the non-uniform deformation.