Li-Zr-Si mixed oxides were irradiated in a mixed radiation field in order to produce tritium through the Li 6 (n,α)H 3 reaction. The Li ZrSiO 4 samples, prepared with different Li:Zr molar ratios (1, 3, 5 and 6), presented high tritium diffusion compared with other lithium ceramics like Li 2 SiO 3 and Li 2 ZrO 3 . Furthermore, their composition and structure were not modified after irradiation. It was also found that Li 2 ZrSi 6 O 1 5 was damaged by irradiation, and that tritium release was moderate in this compound.