Magnetically confined plasmas are the promising way to provide electrical output from a nuclear fusion plant like DEMO. The extrapolation from present day devices is made by a step ladder approach with a series of devices with rising large radius from R=1.5m (ASDEX-Upgrade) via JET (R=3.0m) and ITER (R=6.0m) to DEMO (R=9.0m). Extrapolations of the plasma core conditions are done via scaling laws e.g. for confined time. However, plasma-facing materials and components have already reached a limit in the power handling in the order of 10MW/m2 and can’t be scaled. Thus, the plasma solution has to be adapted and, thus, plasma edge and plasma-surface interaction physics is playing a key role to achieve this solution. Other critical boundaries like the fuel cycle or the dust production from eroded material limit the selection of materials to be used. The different processes and their impact will be introduced and models for the plasma solution discussed.