Tritium Inventory in Li₂O Breeder Material for the SEAFP Helium Cooled Ceramic Blanket

The analysis of the tritium inventory in Li₂O, carried out for the Safety and Environmental Assessment of Fusion Power (SEAFP) helium-cooled ceramic blanket, is based on a diffusion and desorption tritium release model. Within the specific range of breeder temperatures taken into account, desorption was the dominant mechanism so it can be defined as the rate controlling step. At steady state, the model for the tritium inventory in the solid Li₂O breeder is supported by a computer code for several operating conditions. At reference conditions of breeder temperatures, by varying the mean grain radius from 1 to 5 µm, a tritium inventory from 0.5 to 2.8 g can be obtained. A helium purge gas velocity from 0.1 to 0.4 m/s gives rise to gas pressure losses from 0.22 to 0.9 MPa, which could probably be reduced by increasing the pebble diameter to 1 mm. This breeder configuration seems to ensure reactor safety.