Model experiments for tritium behavior in pure and Al-doped lithium orthosilicate by using ionic conductivity measurements

AbstractModel experiments for tritium behavior in lithium orthosilicate (Li4SiO4) and Al-doped lithium orthosilicate (Li3.7Al0.1SiO4) were carried out by “in situ” ionic conductivity measurements using 120 MeV oxygen-ion and 60 MeV lithium-ion irradiation. On the assumption that the tritium migration behavior is closely related to the ionic conductivity reflecting the lithium-ion diffusion, it is considered from experimental results on the conductivity that irradiation effects on tritium diffusivity in Li4SiO4 and Li3.7Al0.1SiO4 can be proposed to be as follows. The tritium diffusivity in the post-irradiation condition for Li4SiO4 increases with the fluence in the temperature range 413 to 673 K. For Li3.7Al0.1SiO4, the tritium diffusivity in the post-irradiation condition increases with the fluence in the temperature range 373 to 413 K, while the diffusivity hardly changes with the fluence in the temperature range 443 to 503 K. Furthermore, there is a possibility of enhancement of tritium diffusion under irradiation for both Li4SiO4 and Li3.7Al0.1SiO4, and the tritium diffusivity of Li3.7Al0.1SiO4 is higher than that of Li4SiO4 under irradiation as well as before irradiation.