Development of insulating coatings for liquid metal blankets

It is shown that self-cooled liquid metal blankets in tokamaks with high magnetic fields are feasible only with electrically insulating coatings at the duct walls. The requirements for the insulation properties are estimated by simple analytical models. Candidate insulator materials are selected, based on their insulating properties and thermodynamic considerations. Different fabrication technologies for insulating coatings are described. The status of the knowledge on the most crucial feasibility issue, i.e. the degradation of the resistivity under irradiation, is reviewed.