Evaluation of remote maintenance schemes by plasma equilibrium analysis in Tokamak DEMO reactor

Uto, Hiroyasu; Tobita, Kenji; Asakura, Nobuyuki; Sakamoto, Yoshiteru

The remote maintenance schemes in DEMO reactor categorized by the insertion direction, blanket segmentation and divertor maintenance scheme were evaluated by the plasma equilibrium analysis. Horizontal sector transport maintenance scheme requires the largest total PF coil current, which was 25% larger than that in the small segment transport using the vertical ports with segmented divertor maintenance because the PF coils was located far from plasma surface by larger TF coil. Though the total PF coil current for MHD equilibrium in the unsegmented divertor maintenance (UDM) scheme was about 10% larger than that in the segmentalized divertor maintenance (SDM) scheme, the time required for installation of all divertor cassettes in the UDM is a third of that in the SDM at a rough estimate. From the viewpoint of the simple maintenance operation, the merit of the UDM scheme would be larger than that of SDM.