29th Symposium on Fusion Technology (SOFT 2016)

P4.006 Development of pellet injection system for KSTAR

8 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 6

Poster A. Experimental Fusion Devices and Supporting Facilities P4 Poster session

Speaker

Soo-Hwan Park (Advanced Technology Research Center)

Description

KSTAR (Korea Superconducting Tokamak Advanced Research) has used gas puffing system as main fueling method since 2008. Up to date total fueling efficiency of gas puff is less than 30 %. Pellet injection is more effective technique to control plasma density than gas puffing system and supersonic molecular beam injection. Many fusion devices such as JET, Tore Supra, ASDEX-U, HL-2A, EAST, and LHD have already installed the pellet injection system (PIS) and then have shown the impressive results of plasma density control and ELM (Edge Localized Mode) mitigation. Pellet injection system for KSTAR consists of pellet injector which injects pellets of hydrogen isotope (diameter of 2 mm, length of 1.5 to 2 mm) at speed above 200 m/s with injection frequency of 1~20 Hz, 2 stage differential pumping system, guide tube, control system and so on. It is planned to inject pellets through high field side and increase plasma performance. The specification of KSTAR pellet injection system, design of differential pumping system and guide tube, as well as configuration of control system together with test results achieved in 2016 are presented.