Effect of surface water on tritium release behavior from Li4SiO4

Abstract

a b s t r a c tThe tritium release model to represent the release behavior of bred tritium from solid breeder materials has been developed by the blanket group of Kyushu University. It has been found that water is released to the purge gas from solid breeder materials and that this water affects the tritium release behavior. In this study, the amount of surface water released from Li 4 SiO 4 is quantified by the experiment. In addition, the tritium release behavior from Li 4 SiO 4 are estimated based on the tritium release model using parameters obtained in our studies under conditions of commercial reactor operation and ITER test blanket module operation. The effect of the surface water on tritium release behavior is discussed from the obtained results. Moreover, the tritium inventory of Li 4 SiO 4 is discussed based on calculation under the unsteady state condition. Further, the effects of grain size and temperature on distribution of tritium inventory under the steady state condition are evaluated, and the optimal grain size is discussed from the view point of tritium release from Li 4 SiO 4 .

Effect of water adsorption on tritium release from Li4SiO4

“…Since B9-8 stored in the dry container for a longer time than B9-1 and this is the only variable between these two sub samples, it is reasonable to conclude that this storage process affected chemical form of released tritium. It has been reported in the literature that Li 4 SiO 4 had large water adsorbing capability [8,14,15], thus different amount of water may be adsorbed during sample handling process and affect tritium release behavior.…”

“…Lithium orthosilicate (Li 4 SiO 4 ), as one of candidates of lithium ceramic breeder for fusion reactor, was researched previously by in-pile and out-of-pile tritium release experiments [1][2][3][4][5][6][7][8][9]. But the results of these experiments vary widely.…”

“…On the contrary, ceramic breeders are usually purged directly in a sealed capsule without contacting with atmosphere in in-pile experiments. Considering Li 4 SiO 4 had large water adsorbing capability [8,14,15], it is thought that water may be adsorbed on the sample during those transfer and storage processes and thus affects tritium release behavior.…”