PMI in Large Tokamaks

With the advances of plasma confinement, research targets of plasma material interactions (PMI) have been changing. Now, durability of plasma-facing materials (PFM) to steady and transient power load and tritium (T) retention are main subjects. Nevertheless, no tokamaks could have given such high-power load as expected in a reactor. Only JET is now working to give power load a little less than that expected in the reactor. However, after changing its PFM from carbon-based materials to ITER like Wall, i.e. Be for first wall and W for divertor, the power load has been carefully controlled not to destroy the W divertor. In this respect, the previous carbon-based divertor allowed higher power load, and PMI data including effects of giant ELM, and disruption were and are useful for designing plasma-facing component for ITER and a reactor. This chapter introduces PMI observed in present large tokamaks important for foreseeing PMI and suggests necessary works for construction of a fusion reactor.