The ASDEX Upgrade tokamak (AUG) has been in operation since 1991. After a step-wise introduction of tungsten as plasma facing material, since 2007, AUG has complete tungsten/metal plasma facing components (PFCs). The conversion to tungsten PFCs required some adaptions to the plasma operation, namely enhancements of central wave heating for tungsten accumulation avoidance and a minimum gas puffing rate for reduction of the tungsten source at the outer plasma. AUG operates a versatile heating and current drive system, consisting of neutral beam injection, electron cyclotron resonance heating and current drive and ion cyclotron range of frequencies (ICRF) heating systems as foreseen in ITER. Since high central radiative losses by tungsten were observed during ICRF operation, an improved antenna pair with three antenna stripes was installed which considerably reduced the tungsten source related to ICRF operation. This paper describes aspects of the AUG operation preparing the scientific exploitation, like boronization schedule, plasma breakdown, and startup. Program setup and performance and failure statistics are also presented. Main failure causes are related to deterioration of electronics and the implementation of new actuators into existing, complicated systems.
This paper describes the operation of the ASDEX Upgrade tokamak, a fusion research device that has been in use since 1991. It covers the transition to using tungsten as the main plasma-facing material, the heating and current drive systems, and the overall performance and reliability of the device.