Tritium transport code in Li₂TiO₃ pebbles were developed in this study. In the simulation code, tritium transports in a grain, a closed-pore and an opened-pore were modeled and combined. The tritium transport in grain was modeled by the tritium diffusion, trapping/detrapping by defects, and the annihilation process of defects. The adsorption/desorption equilibrium of diffusing tritium gas molecule was modeled for the tritium transports in opened-pores. A vacant-core and shell model was used to model the tritium transport in closed-pores. The results by simulation code suggested that the tritium trapping by closed-pores would result in the shift of tritium release toward higher temperature side as dissociation of tritium gas molecule in closed-pores requires higher activation energy.