Speaker
Larry Baylor
(Oak Ridge National Laboratory)
Description
The formation and acceleration of cryogenically solidified pellets of hydrogen isotopes has long been under development for fueling fusion plasmas. Fueling with DT pellets injected from the high field side wall has been proposed for future burning plasma tokamak devices. In addition to fueling, smaller shallow penetrating pellets of deuterium injected from the low field side wall have been shown to be capable of triggering rapid small edge localized modes (ELMs) to limit heat flux damage from large naturally occurring ELMs. Another application of pellet injection is that of disruption mitigation where large pellets of neon, argon, and deuterium mixtures are produced and shattered upon injection into disrupting plasmas to quickly radiate the plasma energy in order to mitigate possible damage to in-vessel components.
The pellets for fueling and ELM triggering need to be formed continuously for fusion applications. Screw extruder systems are under development that can produce either fueling size pellets or ELM triggering pellets in steady state. The required throughput for future burning plasma devices is well beyond that for present day devices and requires stable cooling from a super critical helium source. The large shattered pellets for disruption mitigation are formed in-situ in a pipe gun device and held intact until needed during a disruption. Pressurized gas is also used to accelerate these pellets, but the gas enters the vessel and is not captured. Prototypes of pellet injectors for these applications have been developed and tested in the laboratory and deployed on present day experiments. Details of these injector designs and their applicability for future burning plasma devices will be presented.
Co-authors
Larry Baylor
(Oak Ridge National Laboratory, Oak Ridge, TN, United States)
Steve Combs
(Oak Ridge National Laboratory, Oak Ridge, TN, United States)
Steve Meitner
(Oak Ridge National Laboratory, Oak Ridge, TN, United States)
