Speaker
Igor Vinyar
(PELIN)
Description
High frequency pellet injectors have been developed for edge localized mode mitigation and plasma fuelling of the EAST and KSTAR tokamaks. Each pellet injector is able to inject solid deuterium or hydrogen pellets at steady state mode. Both injectors consist of a continuous ice generator based on a screw extruder cooled by liquid helium and pneumatic punches for pellet fabrication and acceleration.
The EAST pellet injector is able to inject 1.5 mm diameter and 1.2-1.8 mm length pellets at frequency 1-50 Hz with velocities up to 230 m/s. Injection reliability over 95% has been confirmed during several 100 s cycles of continuous D2 pellet injection at 50 Hz. Pellets are injected by two modules working in turn at 1-25Hz each. Injection modules are placed in one vacuum chamber and cooled by common cooling circuit. Pellets injected by each module fly towards a tokamak chamber through a common guide tube. Two valves and an electromagnet are used for propellant gas admission to drive a puncher forward-backward inside the ice generator to form a pellet, accelerate it and remove gas from each module.
The KSTAR pellet injector has been designed to inject 2 mm diameter and 1.5-2.0 mm length pellets with minimal velocity 200 m/s at frequency up to 20 Hz. Contrary to the pellet injector for the EAST tokamak, pellets for KSTAR are formed by a puncher driven by a valve at pressure which can be set independently from a pressure value for pellet acceleration. Besides a constant Nd magnet is used for the puncher fixation and no valves are applied to remove propellant gas from the ice generator and barrel.
The pellet injectors designs as well as test results are presented and discussed.
Co-authors
Alexander Lukin
(PELIN, LLC., Saint-Petersburg, Russian Federation)
Changzhen Li
(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
Hong-Tack Kim
(National Fusion Research Institute, Daejeon, South Korea)
Hyun-Ki Park
(National Fusion Research Institute, Daejeon, South Korea)
Igor Vinyar
(PELIN, LLC., Saint-Petersburg, Russian Federation)
Jiansheng Hu
(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
Jonghwa Lee
(VITZROTECH Co., Ansan, South Korea)
Juhyoung Lee
(VITZROTECH Co., Ansan, South Korea)
Pavel Reznichenko
(PELIN, LLC., Saint-Petersburg, Russian Federation)
Soo-Hwan Park
(National Fusion Research Institute, Daejeon, South Korea)
Xinjia Yao
(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
Yue Chen
(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
