In-pile tritium extraction from samples of lithium aluminate

Abstract Several in-pile irradiation experiments on samples of lithium aluminate provide tritium retention and release data. Such as for all tritium breeders, the interpretation of results is not straightforward. All the results are not explained if only the kinetic contributions to the tritium inventory, diffusion or mass transfer resistance at the solid-gas interface, are considered. In particular, it is necessary to consider tritium adsorption at grain surfaces in order to explain that, at higher temperatures, small grain samples have a higher tritium inventory than samples with large grains. However, at lower temperatures, tritium retention is lower with smaller grains, and above 450°C and with the addition of hydrogen to the sweep gas, the tritium residence time is less than one day. Some nonreproducibility in the results shows that parameters playing a role in the tritium release are not all clearly identified. A more accurate characterization of the surface state of the samples is required.