Deuterium retention of ferritic steel irradiated by energetic hydrogen ions

Ferritic steel (F82H) was irradiated by energetic hydrogen ions to make a irradiation damage. The damaged ferritic steel was irradiated by deuterium ions with energy of 1.7 keV in order to investigate the retention and desorption behavior of deuterium. The deuterium ion fluence was taken up to 5 × 1018 D/cm2. The amount of retained deuterium increased as the deuterium ion fluence and saturated at 1 × 1018 D/cm2. It was clearly seen that the amount of retained deuterium increased as the damage caused by the hydrogen ion irradiation. For example, the amount of retained deuterium in the sample with 4 dpa was several times larger than that in the sample without damage. It was also seen that the desorption temperature approximately 70 K increased compared with that without damage. These results suggest that the number of trapping site and trapping energy for fuel hydrogen increases owing to the irradiation damage. The present results show that both fuel hydrogen recycling and in-vessel tritium inventory increases by the irradiation damage.