Poloidal distribution of penalty factors for DEMO Single Module Segment with limiters in normal operation

Poloidal distribution of penalty factors for DEMO Single Module Segment with limiters in normal operation

Poloidal distribution of penalty factors for DEMO Single Module Segment with limiters in normal operation 150 150 Mathew
UKAEA-CCFE-CP(22)08

Poloidal distribution of penalty factors for DEMO Single Module Segment with limiters in normal operation

The charged particle heat load assessed for the DEMO Single Module Segment First Wall (FW) during current off-normal plasma scenarios underlines that protection is needed for avoiding/reducing damage to the Breeding Blanket FW due to the deposition of a huge amount of energy in a small timescale. Within the “Key Design Integration Issue 1”, an iterative teamwork has led to FW and limiter designs that keep the flat-top maximum heat load on both the FW and limiter Plasma-Facing (PF) surfaces within engineering limits. The limiter strategy appears promising for both normal and off-normal plasma events, therefore study will be focussed on a FW equipped with limiters. As a continuation of the work started in [1], which has highlighted the weakest point of the older FW design and led to the new FW layout, the impact of misaligned segments and limiters on the charged particle heat flux pattern is investigated for the ”limited” FW (i.e. FW protected by limiters). The study is carried out by 3D field line tracing codes SMARDDA/PFCflux and covers normal operation scenarios (Ramp-up and steady-state) with the aim of producing heat flux penalty factor maps to identify the worst-case scenarios. As far as the normal transient events are concerned, the results in [1] are updated. Since in steady-state operation deformation of in-vessel components due to mechanical loads such as ferromagnetic forces acting on EUROFER97 and the different thermal deformation of adjacent segments lead to the exposure of edges that are shadowed in the FW undeformed configuration, flexible geometrical transformations simulating this kind of normal operation misalignments are implemented for studying the impact of thermally-induced deformations on the heat load map.

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31st Symposium on Fusion Technology (SOFT), Dubrovnik, Croatia, 20 - 25 September 2020
The published version of this paper is currently under embargo and will be available on 21/01/2023