Performance and lifetime assessment of reactor wall and nearby components during plasma instabilities

Surface and structural damage to plasma-facing components (PFCs) due to the frequent loss of plasma confinement is a serious problem for the tokamak reactor concept. The plasma energy deposited on these components during loss of confinement causes significant surface erosion, possible structural failure, and frequent plasma contamination. Surface damage consists of vaporization, spallation, and liquid splatter of metallic materials. Comprehensive multidimensional models that include thermodynamics and thermal hydraulics of plasma-facing materials (PFMs), eroded-debris/vapor atomic physics and magnetohydrodynamics (MDHs), resulting photon radiation and photon transport, as well as liquid splashing and brittle destruction of materials, are used self-consistently to evaluate and assess our current understanding of the lifetime of PFMs and the various forms of damage they experience. Models are developed to study the stability of the vapor shielding layer, erosion of the melt-layer, brittle destruction/explosive erosion, and the issues involved therein. (C) 1998 Elsevier Science B.V. All rights reserved.