Characteristic test of dual shattered pellet injection systems of KSTAR

Soo Hwan Park, Kun Su Lee, Jayhyun Kim, Hyun Myung Lee, Larry R. Baylor, Jeongwon Yoo, Jae In Song, In Sik Woo, Sang Won Yun, Kwang Pyo Kim, Steven J. Meitner, Trey E. Gebhart, Michael Lehnen, Kap Rai Park

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Dual shattered pellet injection (SPI) systems are installed in KSTAR (Korea Superconducting Tokamak Advanced Research) to study disruption mitigation in support of the ITER DMS (Disruption Mitigation System) design activities. KSTAR has two identical pellet injectors that can shoot pellets simultaneously from opposite toroidal locations. Each injector can shoot up to of three different diameter pellets. The pellet integrity and velocity after formation have been measured using microwave cavity (MWC) systems since 2019. However, this diagnostic provides only limited information on the pellet integrity, especially for partially broken pellets. Therefore, an optical pellet diagnostic (OPD) system monitoring the pellet has been installed in the first stage viewport of the differential pumping system and is operational since 2021. The KSTAR SPI systems offer a wide parameter range that must be characterized before the experimental campaign. To satisfy the experimental requirements, a proper procedure for pellet formation and acceleration must be commissioned. We carry out the commissioning by varying pellet parameters such as formation duration, temperature, heating, propellant gas pressure, and pulse length. The resulting pellet velocity, integrity, and tilt can be measured with the OPD system. These tests can be performed without plasma operation because no additional information is needed from the plasma response to the injection. This paper describes the results of the characteristic tests of single and multiple injections of dual SPI.

Original languageEnglish
Article number113911
JournalFusion Engineering and Design
Volume194
DOIs
StatePublished - Sep 2023

Funding

This study was supported by the Korean Ministry of Science and ICT under the KSTAR project. This work was supported by the Oak Ridge National Laboratory managed by UT-Battelle , LLC for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725 , by the U.S. Department of Energy under Contract No. DE-SC0020299 , and by the ITER Organization under Contracts IO/CT43-1830 , 1909, 1918, 2034, 2653. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

FundersFunder number
U.S. Department of EnergyDE-AC05-00OR22725, DE-SC0020299
Oak Ridge National Laboratory
UT-Battelle
Instituto Tecnológico y de Energías RenovablesIO/CT43-1830
Ministry of Science and ICT, South Korea

    Keywords

    • Disruption
    • Dual injectors
    • KSTAR
    • Shattered pellet injection

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