Kinetics of Tritium Release from Thermal Neutron-Irradiated Li_0.17Pb_0.83

Tritium release behavior for thermal neutron-irradiated Li_0.17Pb_0.83 eutectic alloy was studied. Main tritium release peak was observed in the temperature just a little higher than melting point in a thermal desorption spectrometry (TDS) experiment. Most of tritium release from Li_0.17Pb_0.83 eutectic alloy was found to be governed by diffusion process from the results of isothermal annealing experiments. Tritium diffusivity in a liquid state of Li_0.17Pb_0.83 eutectic alloy was evaluated to be D = 4.7 × 10^-8 exp(-0.13 eV/kT) m² s^-1 . Tritium diffusivity was increased by the phase transition of Li_0.17Pb_0.83 eutectic alloy from a solid state to a liquid state, resulting in the sharp tritium release peak that appeared in TDS spectrum. In addition, about 4% of tritium was trapped in Li_0.17Pb_0.83 eutectic alloy as Li-T bond.