AbstractOne of the objectives assigned to a DEMO blanket will be to limit tritium leakage to the steam circuit by permeation through the steam generator tubing of the tritium unavoidably present in the coolant. The control of these losses will require, on one hand, to minimize the amount of tritium reaching the coolant under both nominal and accidental conditions, and, on the other hand, to have an efficient tritium recovery process and chemistry control for maintaining at a low level the concentration in reduced tritiated species in the coolant.