AbstractThermal fatigue of the divertor plate is one of the key issues which governs the lifetime of the divertor plate. A thermal cycling experiment of divertor mock-ups was carried out to investigate the thermal fatigue behavior of the divertor structure in a high heat flux test facility at Japan Atomic Energy Research Institute (JAERI). A cyclic heat flux of 5 MW/m2 was loaded onto the mock-ups to simulate the steady state thermal condition of ITER divertor plate. A pulse duration of 30 s was selected so that the mock-ups reach thermal steady state. The mock-ups showed water leakage due to thermal fatigue cracking of the cooling tube after 400 cycles. The fatigue crack was observed at the top of the cooling tube. According to a numerical analysis, the maximum strain amplitude was over 5% at the top of the cooling tube. The cracking of the cooling tube was caused by the large strain concentration due to structural discontinuity of the copper heat sink. It was found that the heat sink block should be separated into smaller blocks to reduce the strain concentration at the cooling tube.
偏滤器板的热疲劳是决定偏滤器板寿命的关键问题之一。在日本原子能研究所（JAERI）的高热负荷试验装置中，对偏滤器模型件进行了热循环实验，以研究偏滤器结构的热疲劳行为。为模拟ITER偏滤器板的稳态热工况，对模型件施加了5 MW/m²的循环热负荷。脉冲持续时间选定为30 s，以使模型件达到热稳态。经过400次循环后，模型件因冷却管的热疲劳开裂而出现漏水。疲劳裂纹出现在冷却管的顶部。根据数值分析，冷却管顶部的最大应变幅值超过5%。冷却管开裂是由铜热沉的结构不连续性导致的大应变集中引起的。研究发现，应将热沉块分割为更小的块体，以降低冷却管处的应变集中。