The impacts of blanket on CFETR ohmic breakdown

Abstract China Fusion Engineering Test Reactor (CFETR) design is under way, it is necessary to develop an optimized scenario for plasma breakdown and current ramp-up, and to evaluate the consequent design constraints. A good initial magnetization (IM) and volt-seconds optimization are carried out for the ohmic breakdown based on the 2D TokSys model, giving the maximum volt-seconds that the magnetic coils can provide. Take IM as the initial condition, the ohmic breakdowns on the conditions that the blanket has different equivalent resistivities and positions are optimized. Comparisons of the optimized values and the target values are made. The ohmic breakdown without blanket is calculated as well, as a reference, the minimum equivalent resistivity of blanket required to meet the breakdown condition is obtained. Both initial magnetization and ohmic breakdown optimization could serve as preliminary references for the CFETR coils and blanket designs.