Tritium transfer in fusion reactor is one of major risk of contamination in fusion plant, as well for environment impact as for worker inside plant. The main purposes of this study is to calculate tritium concentration in each containment, taking into account containment design, leakage rate of tritium contaminated cooled water and atmospheric detritiation system. It is tried to optimize contamination level in each cases studied, on technico economical point of view, taking into account investment and operating costs, by multicriteria analysis. A computer code called TRITO (Tritium Transfer Optimization) was performed to solve for all conditions, including the two main options: one confinement and two confinement systems.