Self-consistent analysis of the effect of runaway electrons on plasma facing components in ITER

Abstract

Physical and computational models are developed, used and benchmarked for studying the response of ITER tokamak plasma facing components to runaway electron impact following a plasma disruption. The energy deposition, temperature evolution and material melting thickness are calculated for a wide range of runaway electron parameters, namely, electron kinetic energy, magnetic field, energy partition ratio (along and across magnetic field direction) impact duration, and wall material composition. It is shown that the electron energy partition ratio will have a significant effect on the wall heat load with melting of the first wall with beryllium armor possible. If tungsten armor is used instead, the surface of the mockup is overheated and melted for all ranges of studied parameters of the runaway electrons. Using an insert of a thin layer of a high-Z material inside the beryllium armor can mitigate the heat load in the armor and heat sink structure.