Modeling of in-pile experiments on tritium release from molten lithium-lead

Modeling of in-pile tritium release from molten lithium-lead was performed. Three models were considered: (1) recombination limited release, (2) bulk diffusion with subsequent recombination, and (3) fast bulk transport with slow skin layer diffusion followed by recombinative desorption. All the three models gave equally good agreement with experimental kinetic curves of tritium release. The decision about which model is valid can only be made having additional information. For the case of the particular experiment considered, this information was available, and it was concluded, that the skin layer model must be applied to this particular experiment. The recombination coefficient and the thickness of the layer were obtained.