Insulating performance requirements for the coating material in the ITER DFLL electromagnetic TBM based on the MHD analysis

Materials for Fusion Applications

“…In this application, the coatings would have to serve as electrical insulators, corrosion and permeation barriers [49]. The MHD pressure drop strongly depends on the coating resistance; for proper insulation, the product of resistivity and thickness should be >100 Ω cm 2 [11]. Similarly to tritium permeation barriers, the insulating capability is influenced by the presence of defects such as cracks [11].…”

“…The MHD pressure drop strongly depends on the coating resistance; for proper insulation, the product of resistivity and thickness should be >100 Ω cm 2 [11]. Similarly to tritium permeation barriers, the insulating capability is influenced by the presence of defects such as cracks [11]. Therefore, dense, contiguous and/or self-healing coatings are desirable.…”

Numerical study of MHD pressure drop in rectangular ducts with insulating coatings

“…For fully developed flow in perfect coating duct with uniform thickness t c , the pressure drop is given by the following analytical formulas [9]:…”

“…In contrast, insulating ducts make current circuits close in extremely thin boundary layers, named Hartmann layers, which causes relatively small MHD effects. Insulating coating is effective to reduce MHD effects [5][6][7][8], and it has been widely used in the design of fusion blankets [1,4,9,10]. However, a perfect coating without cracks cannot be guaranteed in manufacture and severe operation scenarios.…”

“…Theoretic analyses of MHD pressure drop were summarized in Refs. [9][10][11][12]. The influences of coating cracks on side walls in 2D were shown in Refs.…”