An analytic model taking account of multiple structures and temperature gradient was developed for tritium permeation and inventory in an international thermonuclear experimental reactor divertor. It was applied to calculate the tritium permeation and inventory in Be/Cu and W/Cu options of the divertor components. The total tritium permeation and mobile inventory in the Be/Cu option were calculated to be 0.81 mg/s and 6.0 kg, and those in the W/Cu option were 0.0071 mg/s and 6.7 g. The mobile inventory in the Be/Cu option decreases with increasing operation time, while that in the W/Cu option decreases initially and then increases.