Thick Co-Deposits and Dust in Controlled Fusion Devices with Carbon Walls: Fuel Inventory and Growth Rate of Co-Deposited Layers

Recent results regarding the formation of co-deposits, fuel accumulation and overall material transport at the TEXTOR tokamak are described. Two categories of brittle flaking co-deposits were identified: ( i ) smooth stratified layers of a thickness of up to 50 µm and a fuel content of up to 16 at.% , ( ii ) granular and columnar structures reaching 1 mm in thickness and con-taining around 0.5 at.% of fuel species. They were formed on the blades of the toroidal belt pump limiter (~15000 s of plasma operation) and on the neutral-iser plates of this limiter (~90000 s), respectively. A comparison is made to the fuel inventory measured in other controlled fusion devices with carbon walls.