During its last maintenance shutdown, the interior of the ASDEX Upgrade tokamak located at IPP Garching has been fully equipped with tungsten-coated plasma facing components (PFCs) including the divertor target plates. Since studies indicate that tungsten (W) is at present the only viable material for the first wall of a fusion reactor, the start-up of ASDEX Upgrade with the all-tungsten wall, the first of its kind worldwide, has received special attention. Following discussions with colleagues from all over the world, the ASDEX Upgrade team decided to start up the machine without any additional coating of the plasma facing components. In particular, no boronisation was applied, which is usually done to bind (getter) oxygen and to reduce impurities released from the PFCs, mainly helping the production of the hydrogen (deuterium) plasma.

So far, this start-up seems to be successful. After three weeks of conditioning, discharges are now possible that meet the ITER requirements of good confinement (H=1) and stability (βN=2) at high density. The main aim of the present campaign will be to characterise fully the compatibility of ITER operational scenarios with the alltungsten wall.