Plasma Facing Component Development: Boundary Layer Physics and Component Engineering^*

* This work was supported by the U.S. Department of Energy under Contract DE-AC04-76DP00789.

Abstract

Tokamaks currently in operation deposit on the order of 1-30 MW/m² onto plasma facing surfaces during normal operation and hundreds of MW/m² for shorter periods of time (0.1–3 ms) during disruptions. Disruption deposited energies on future high-power tokamaks may be well in excess of 20 MJ/m² Design of plasma facing components (PFCs) for such severe environments requires considerable advancements in materials development, armor tile bonding to actively cooled substrates, heat transfer, and many other areas of engineering concern. Considerable improvements in PFC performance, reliability and lifetime can also be accomplished through improved understanding and control of the edge plasma boundary layer. This paper covers both engineering and edge plasma physics issues that must be addressed in the development of reliable PFCs for ITER. Several specific examples are addressed since a complete treatment of all critical development issues would be lengthy. Topics covered include impurity generation and transport in the boundary layer plasma, materials response to intense pulsed disruption heat loads, runaway electron generation during disruptions, high heat flux performance and PFC fabrication issues. These topics are illustrative examples of the variety of complex issues that must be addressed in the development and design of PFCs.

Notes

* This work was supported by the U.S. Department of Energy under Contract DE-AC04-76DP00789.