Initial phase wall conditioning in KSTAR

Suk Ho Hong, Kwang Pyo Kim, Sungwoo Kim, Jong Ho Sun, Dong Su Lee, Hyun Jong Woo, Sang Yong Lee, Sang Hwa Lee, Eun Kyung Park, Sang Joon Park, Kyung Min Kim, Kun Su Lee, Sun Ho Kim, Jong Su Kim, Sun Jung Wang, Jae Min Park, Woong Chae Kim, Hak Kun Kim, Kap Rai Park, Hyung Lyeol YangYeong Kook Oh, Jong Gu Kwak, Hoon Kyun Na, Jae Yong Kim, Kyu Sun Chung

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The initial phase wall conditioning in KSTAR is depicted. The KSTAR wall conditioning procedure consists of vessel baking, glow discharge cleaning (GDC), ICRH wall conditioning (ICWC) and boronization (Bz). Vessel baking is performed for the initial vacuum conditioning in order to remove various kinds of impurities including H2O, carbon and oxygen and for the plasma operation. The total outgassing rates after vessel baking in three successive KSTAR campaigns are compared. GDC is regularly performed as a standard wall cleaning procedure. Another cleaning technique is ICWC, which is useful for inter-shot wall conditioning under a strong magnetic field. In order to optimize the operation time and removal efficiency of ICWC, a parameter scan is performed. Bz is a standard technique to remove oxygen impurity from a vacuum vessel. KSTAR has used carborane powder which is a non-toxic boron-containing material. The KSTAR Bz has been successfully performed through two campaigns: water and oxygen levels in the vacuum vessel are reduced significantly. As a result, KSTAR has achieved its first L-H mode transition, although the input power was marginal for the L-H transition threshold. The characteristics of boron-containing thin films deposited for boronization are investigated.

Original languageEnglish
Article number103027
JournalNuclear Fusion
Volume51
Issue number10
DOIs
StatePublished - 2011 Oct 1

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    Hong, S. H., Kim, K. P., Kim, S., Sun, J. H., Lee, D. S., Woo, H. J., Lee, S. Y., Lee, S. H., Park, E. K., Park, S. J., Kim, K. M., Lee, K. S., Kim, S. H., Kim, J. S., Wang, S. J., Park, J. M., Kim, W. C., Kim, H. K., Park, K. R., ... Chung, K. S. (2011). Initial phase wall conditioning in KSTAR. Nuclear Fusion, 51(10), [103027]. https://doi.org/10.1088/0029-5515/51/10/103027