Within the framework of EUROfusion DEMO First Wall and limiter design activities, the protection of the First Wall against power deposition peaks is being considered. During steady-state operation, the radiative power from the plasma could be considered uniformly spread on plasma-facing components. However, the presence of openings (i.e. gaps between segments and ports) and the introduction of limiters breaks the continuity of the wall and opens the possibility of localized high heat flux values on toroidally facing gaps due to charged particles striking the wall. These fluxes can be amplified by misalignments between components upon manufacturing, assembly or under operational conditions. In this paper, the 3D field line tracing codes SMARDDA and PFCflux are used for studying the impact of misalignment on the heat load distribution for a periodically segmented DEMO First Wall, specifically the Single Module Segment Concept. The work covers normal operation (ramp-up/down and steady-state), H-L transition and off-normal transients such as Upper Vertical Displacement Events (UVDEs), considering both the cases of bare First Wall (without limiters, as reference) and First Wall protected by limiters. Heat flux penalty factor maps have been created to identify the worst cases among the ones analyzed. The related heat flux maps are relevant for thermal assessments of a simplified DEMO model to be performed later on, particularly in terms of maximum temperature values for the current DEMO design.
DEMO First Wall misalignment study by 3D field line tracingDEMO First Wall misalignment study by 3D field line tracing https://scientific-publications.ukaea.uk/wp-content/themes/blade/images/empty/thumbnail.jpg 150 150 UKAEA Opendata https://secure.gravatar.com/avatar/c7700c5c020bdaef41f283eb9cb3b887?s=96&d=mm&r=g
The published version of this paper is currently under embargo and will be available on 25/06/2022