Performance issues for actuators and internal components during long pulse operation Tore Supra experience

In a fusion device, long pulse operation adds a set of specific constraints on actuators and internal components. Some of these issues are analyzed through the 20 years experience of Tore Supra which is to date the largest Tokamak able to run long duration discharges (hundreds of seconds). Superconducting magnet operation, RF heating and current drive as well as particle fuelling issues are discussed. The impact on operation of the actively cooled environment is also assessed. Material erosion and fuel retention results tend to discard the carbon as armor material for a fusion reactor. Real time survey of the surface temperature of critical components integrated into the plasma control systems allows for safe operation at ITER relevant heat fluxes and scenario control close to the limits.