Status of Plasma Facing Material Studies and Issues toward DEMO

Abstract

This review paper presents status of research activity of plasma facing materials, mostly tungsten and crit- ical issues towards DEMO reactors. A helium effect on tungsten surface morphology and its impact on fusion reactors and a pulsed heat effect to tungsten are briefly summarized. For DEMO, effects of steady-state operation and heavy neutron irradiation are important subjects to investigate. Present understandings on these are briefly summarized. Finally, issues of helical system towards DEMO will be discussed.