Can current Tokamak reactor designs survive any single unmitigated transient event?*

Successful operation of tokamak reactors such as ITER-like and future commercial plants is critically determined by the effects of transient events on plasma facing materials (PFMs) and nearby components. Transient plasma events like disruptions, ELMs, and runaway electrons can cause severe damage to these materials; seriously affecting/stopping the operations of these reactors. We used our HEIGHTS comprehensive simulation package to predict ITER-like components response during these transient events. HEIGHTS integrate full 3D models starting from the lost hot core plasma particles through SOL, deposition on the divertor surface, and the resulting evolution and generation of a secondary mini-plasma of wall/divertor materials. HEIGHTS also simulate detail runaway electrons deposition and transport through PFMs, structural materials, and coolant channels. Significant damage can result from a single event of a disruption and an ELM on all internal components including the reflector, dome structure, stainless steel tubes, and even parts of the first walls due to the high radiation power of the secondary mini-plasma generated from high-Z divertor materials. A single event of runaway electrons can also cause serious damage to wall and structural materials as well as coolant channels.  Potential design solutions, such as advanced composite materials, pellet injections, neutral gas puffing, etc., are presented with their pros and cons to mitigate the damage and will also be compared and discussed.