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

Hiroyasu Utoh, Kenji Tobita, Nobuyuki Asakura, Yoshiteru Sakamoto

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The remote maintenance schemes in a DEMO reactor are categorized by insertion direction, blanket segmentation, and divertor maintenance scheme, and are quantitatively evaluated by analysing the plasma equilibrium. The positions of the poloidal field (PF) coil are limited by the size of the toroidal field (TF) coil and the maintenance port layout of each remote maintenance scheme. Because the PF coils are located near the larger TF coil and far from the plasma surface, the horizontal sector transport maintenance scheme requires the largest part of total PF coil current, 25% larger than that required for separated sector transport using vertical maintenance ports with segmented divertor maintenance (SDM). In the unsegmented divertor maintenance (UDM) scheme, the total magnetic stored energy in the PF coils at plasma equilibrium is about 30% larger than that stored in the SDM scheme, but the time required for removal and installation of all the divertor cassettes in the UDM scheme is roughly a third of that required in the SDM scheme because the number of divertor cassettes in the UDM scheme is a third of that in the SDM scheme. From the viewpoint of simple maintenance operations, the merit of the UDM scheme has more merit than the SDM scheme.

Original languageEnglish
Pages (from-to)2588-2593
Number of pages6
JournalFusion Engineering and Design
Issue number11
Publication statusPublished - 2014 Nov 1


  • DEMO
  • Divertor maintenance
  • Plasma equilibrium
  • Poloidal field coil
  • Remote maintenance


Dive into the research topics of 'Evaluation of remote maintenance schemes by plasma equilibrium analysis in tokamak DEMO reactor'. Together they form a unique fingerprint.

Cite this