ELMs and Disruptions in ITER: Expected Energy Fluxes on Plasma-Facing Components from Multi-Machine Experimental Extrapolations and Consequences for ITER Operation
New experimental results on transient loads during ELMs and disruptions in present tokamak devices and their effects on plasma facing materials are described and used to carry out a physics-based extrapolation of the expected loads in ITER reference operating conditions and consequences for the operation of the device. In particular, the achievement of convective Type I ELMs in ITER-like plasma conditions seems to open a way to achieve transient loads which may be compatible with an acceptable erosion lifetime of Plasma Facing Components (PFCs) in ITER. This is reinforced by calculations of the expected erosion lifetime, under these load conditions, which take into account a realistic temporal dependence of the power fluxes on plasma facing components during ELMs and disruptions. On the other hand, the non-ideal behaviour of plasma facing materials seen in dedicated experiments in plasma guns (W cracking and CFC enhanced PAN fibre erosion) may imposed additional constraints to ITER operations well below those evaluated on the basis of average material properties.