High-temperature irradiation damage studies of Indian Reduced Activation Ferritic/Martensitic (INRAFM) steel have been carried out at doses relevant to fusion reactor first-wall irradiation conditions. The samples were irradiated up to 70 dpa with 1.1 MeV Fe ions at various temperatures viz., room temperature (RT), 473 K, 673 K and 773 K, with and without pre-injected helium. Depth-wise distribution of irradiation-induced defects and their thermal stability has been studied using positron beam based Doppler broadening spectroscopy. Samples without pre-injected helium show an overall reduction in S-parameter with respect to the irradiation temperature and no growth of voids has occurred, and complete defect recovery is observed at 673 K. In samples that were pre-injected with helium, a decrease in S-parameter due to annealing of vacancies and the formation of He_mV_n clusters is observed from RT to 673 K, and an increase in S-parameter associated with the growth of helium bubbles is observed at 773 K. Thus, helium is found to be necessary and crucial in stabilization and growth of the bubble cavities.

印度还原活化铁素体/马氏体（INRAFM）钢的高温辐照损伤研究已按与聚变反应堆第一壁辐照条件有关的剂量进行。在室温和室温下，在室温和室温下，分别用1.1 MeV Fe离子和不带预注入氦气的1.1 MeV Fe离子辐照样品至70 dpa。辐射诱导缺陷的深度分布及其热稳定性已使用基于正电子束的多普勒增宽光谱进行了研究。没有预注入氦气的样品相对于辐照温度显示出S参数的总体降低，并且没有出现空洞的增长，并且在673 K下观察到了完全的缺陷恢复。在预注入氦气的样品中，从室温到673 K观察到_m V _n团簇，并且在773 K处观察到与氦气泡的生长相关的S参数的增加。因此，发现氦对于气泡腔的稳定和生长是必要且至关重要的。