Estimation of heat load distribution and W erosion on CFEDR first wall

The heat load distribution on the first wall (FW) and the wall material erosion have been investigated for CFEDR conventional H-mode scenario. The FW shaping has been optimized based on the 3-dimensional assessment of the heat flux distribution for both the start-up and steady-state phases using the PFCflux code. This optimization ensures that the leading edge is protected even with 10 mm misalignment considered for each wall segment. During the start-up phase, the peak heat load is about 0.85 MW/m2 located on the high field side wall, whereas for the steady-state phase, the peak heat load is about 0.64 MW/m2 located at the low field side wall, with the main contribution from the loss of α particles. The FW erosion and tungsten (W) edge transport have been simulated by using the SOLPS-OSM-DIVIMP code package. Simulation results confirm that the W source from the FW can significantly increase the core W density by more than an order of magnitude for the detached divertor conditions, thereby determining the core W concentration. A suitable D2 injection as a trade-off for Ar injection has been demonstrated to effectively reduce W erosion rates while maintaining the core W concentration and material lifetime at an acceptable level for CFEDR.