THERMAL EFFECTS AND OTHER CRITICAL ISSUES OF PLASMA-FACING COMPONENTS

Plasma-Facing Components (PFC) play a critical role in the operation of magnetic fusion devices, particularly for tokamaks. The heat flux incident on these components during both normal and off-normal operations is high and providing sufficient protection to accommodate erosion plus high thermal conductivity to limit surface temperatures and thermal stresses is a serious design problem, especially for high power devices. The current ITER design activity has demonstrated the importance of achieving high performance design for these components and its impact on the overall machine capabilities and availability. Without a solution to the PFC problem, fusion will not become a viable energy producing option. In this paper, problems in PFC design related to thermal effects for both normal and off-normal loads are indicated and discussed. Design approaches to reduce the problem are suggested from the standpoint of machine control and modifying the component design. Our capability to model these effects will also be discussed.