Radiative Heat Load Distribution on the EU-DEMO First Wall Due to Mitigated Disruptions

Abstract The EU-DEMO First Wall (FW) will be a relatively thin structure. In order not to damage this layer, heat loads distributed onto the wall should be carefully controlled. In the case of transient events, as for example plasma disruptions, the steady-state heat load limit ( ∼ 1 - 2 M W / m 2 ) can be largely exceeded. Therefore, when the control system detects an upcoming disruption, Shattered Pellet Injection (SPI) or Massive Gas Injection (MGI) mitigation techniques can be employed to inject impurities and switch off the plasma safely. In the present work, the Monte-Carlo ray-tracing code CHERAB is used to compute the radiative heat load distribution on the EU-DEMO Plasma Facing Components (PFCs) due to a mitigated plasma disruption. Also, by applying newly-developed techniques, the peak radiative load on the PFCs calculated in a previous work is shown to be ∼ 35 % higher with respect to our improved estimate of 488 M W / m 2 . This leaves space for less severe conditions than previously foreseen.