Quasi-steady state plasma operation in the Be/W material mix. From the JET tokamak to ITER

ITER will operate with metallic wall an employ PFCs made of Beryllium at the first wall and Tungsten in the divertor. The positive aspects of the envisaged material mix for ITER have been confirmed (low fuel retention, low erosion and material migration, dust production), but plasma-surface interaction at these metallic components has shown vital impact on the operational space as we all as on the plasma performance. A two weeks period of identical plasma discharges in H-mode conditions accumulating more than 900s of plasma time and more than 30 000 ELMs has been executed to mimic ITER-like plasma discharge conditions which can be expected at half magnetic field operation as foreseen in the start sequence of ITER. Detailed analysis of the discharges as well as associated edge modelling will be presented to allow extrapolation to ITER.