Determination of Tritium Transfer Parameters in Lithium Ceramics Li₂TiO₃ During Reactor Irradiation Based on a...

This paper presents the results of determining the parameters of tritium transfer processes in lithium ceramics Li₂TiO₃ under reactor irradiation conditions. Analysis of sections with a short-term decrease in reactor power allowed numerical determination of the Arrhenius parameters of tritium diffusion (pre-exponential factor and activation energy) based on comparison with in situ experimental data. The obtained values of activation energy (70.2-74.7 kJ/mol) and pre-exponential factor (0.9-2.1 × 10^-8m²/s) demonstrate growth with increasing fluence, which is explained by the accumulation of radiation defects in ceramics. A linear dependence was established between D₀ and E_a, corresponding to the Mayer-Noldel rule. Unlike previously conducted studies based on a phenomenological approach to assessing only the activation energy of diffusion, in this study, a complex model that takes into account temperature gradients, tritium generation, its diffusion, and release from the surface was used. The applicability of such an integrated approach to the analysis of in situ reactor experiments with lithium ceramics was confirmed, and allowed us to estimate changes in the tritium transfer parameters in lithium ceramics Li₂TiO₃ depending on the irradiation time.