Targeting a Versatile Actuator for EU-DEMO: Xenon Doping of Fueling Pellets

Abstract

Xenon is a potential candidate as a pedestal and edge radiator in DEMO, but it is considered troublesome in cases where larger amounts have to be handled in the fuel cycle. Hence, direct and efficient codeposition inside the confined plasma with the fuel injected by means of solid cryogenic pellets is regarded as more favorable than simple gas puffing. At ASDEX Upgrade, investigations are underway to develop a versatile reactor-relevant pellet actuator. Equipped with an accordingly set up pellet launching system and well diagnosed, this all-metal-wall tokamak is well suited for this task. Here, we report on efforts to produce and inject pellets made from deuterium with a reasonable amount of admixed xenon. Results indicate xenon supply via carrier fueling pellets is possible while showing advanced performance. Compared to xenon gas puffing where long latency is observed, presumably due to wall sticking, doped pellets provide much shorter response times. Hence, this first exploration suggests fueling pellets with admixed auxiliary gases can be a versatile, efficient, and fast actuator for additional control features such as, e.g., radiative plasma cooling.