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Lithium titanate, Li 2 TiO 3 , was irradiated with deuterium ions with energy of 1.7 keV and then exposed to helium or helium-hydrogen mixed gas at different temperature, in order to evaluate the effect of exposure gas on removing deuterium from the pebbles. The amount of residual deuterium in the irradiated pebbles after the gas exposure was measured by thermal desorption spectroscopy. The mixing of hydrogen gas into helium gas enhanced the removal amount of deuterium. In other words, the amount of residual deuterium after the heliumhydrogen mixed gas exposure at low temperature was lower than that after the helium gas exposure. The ion irradiation followed by heating for the pebbles was repeated, and the residual amount of deuterium was measured. The residual amount increased with the number of irradiation/heating cycles. The result suggests that the tritium inventory in the blanket in a fusion reactor changes after the operation.

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In order to evaluate tungsten (W) coating performance, thin W film was deposited onto reduced activation ferritic/martensitic steel (F82H) by using rf magnetron sputtering device, then was irradiated at room temperature by 1.7 keV D + ions. After the irradiation, the deuterium retention of the coated sample (W/F82H) was evaluated by thermal desorption spectroscopy (TDS) and compared with those of the F82H and pure W. During TDS measurements, D 2 was desorbed in all materials but HD was only found in significant amount in W/F82H and related to the increase of effective surface area due to the porous film structure. D retention increased with increasing fluence and was accompanied by growth of circular blisters. The size of blisters was limited by the F82H substrate structure.