Erosion effects on tritium permeation and inventory in ITER divertor

The effects of erosion on tritium permeation and mobile inventory in an ITER divertor were examined by an analytic model taking into account multiple structures and temperature gradient. The erosion accelerates the tritium permeation for both Be/Cu and W/Cu options. However, it affects tritium inventory in different ways. For the Be/Cu divertor, the tritium inventory in the Be layer dominates the total, resulting in the reduction of the inventory with decreasing Be thickness. For the W/Cu divertor, on the other hand, the tritium inventory gradually decreases initially and then increases sharply with increasing operation time. This distinct behavior is mainly caused by the difference in relative magnitudes of tritium solubility between Be and Cu, and between W and Cu.