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Bulk-boronized limiter operation in the Wendelstein 7-AS stellarator

Conference:

Abstract

Bulk-boronized graphite (20% boron) has been tested as a limiter material in the Wendelstein 7-AS stellarator. The recycling behaviour and the plasma impurities are compared for the new material and the formerly used TiC-coated graphite with stainless steel and boronized walls. After conditioning the recycling and the oxygen and carbon levels are comparable for both materials. No significant impact of sputter boronization from the limiters on the oxygen level was observed. A drastical reduction of oxygen by about a factor of 10 was obtained only after additional gas boronization. In this case Z[sub eff] is primarily determined by carbon and boron. For ECF standard discharges Z[sub eff][approx equal]2 with P[sub rad]=6% of the input power was found as compared to Z[sub eff]< or approx.3 and P[sub rad]=10% before boronization and Z[sub eff][approx equal]4, P[sub rad]=20% with TiC-limiters. (orig.).
Authors:
Brakel, R; Burhenn, R; Behrisch, R; Grigull, P; Hacker, H; Hildebrandt, D; Hofmann, J V; Mahn, C; Roth, J; Schneider, U; Weller, A; [1]  Hirooka, Y; [2]  W7-AS Team; NI Group; ECRH Group
  1. Max-Planck-Inst. fuer Plasmaphysik, Garching (Germany)
  2. Inst. of Plasma Physics and Fusion Research, Univ. California, Los Angeles, CA (United States)
Publication Date:
Dec 01, 1992
Product Type:
Conference
Report Number:
CONF-920311-
Reference Number:
AIX-24-034632; EDB-93-050877
Resource Relation:
Journal Name: Journal of Nuclear Materials (Journal des Materiaux Nucleaires); (Netherlands); Conference: 10. international conference on plasma-surface interactions in controlled fusion devices, Monterey, CA (United States), 30 Mar - 3 Apr 1992
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; LIMITERS; BORON; GRAPHITE; WENDELSTEIN-7 STELLARATOR; IMPURITIES; COATINGS; COMPARATIVE EVALUATIONS; ELECTRIC DISCHARGES; EXPERIMENTAL DATA; FIRST WALL; QUANTITY RATIO; RECYCLING; SOFT X RADIATION; SPUTTERING; TITANIUM CARBIDES; ULTRAVIOLET SPECTRA; CARBIDES; CARBON; CARBON COMPOUNDS; CLOSED PLASMA DEVICES; DATA; ELECTROMAGNETIC RADIATION; ELEMENTAL MINERALS; ELEMENTS; EVALUATION; INFORMATION; IONIZING RADIATIONS; MINERALS; NONMETALS; NUMERICAL DATA; RADIATIONS; SEMIMETALS; SPECTRA; STELLARATORS; THERMONUCLEAR DEVICES; THERMONUCLEAR REACTOR WALLS; TITANIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; X RADIATION; 700412* - Magnetic Confinement Devices- (1992-)
OSTI ID:
6705703
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0022-3115; CODEN: JNUMAM
Submitting Site:
NLN
Size:
Pages: 431-435
Announcement Date:

Conference:

Citation Formats

Brakel, R, Burhenn, R, Behrisch, R, Grigull, P, Hacker, H, Hildebrandt, D, Hofmann, J V, Mahn, C, Roth, J, Schneider, U, Weller, A, Hirooka, Y, W7-AS Team, NI Group, and ECRH Group. Bulk-boronized limiter operation in the Wendelstein 7-AS stellarator. Netherlands: N. p., 1992. Web.
Brakel, R, Burhenn, R, Behrisch, R, Grigull, P, Hacker, H, Hildebrandt, D, Hofmann, J V, Mahn, C, Roth, J, Schneider, U, Weller, A, Hirooka, Y, W7-AS Team, NI Group, & ECRH Group. Bulk-boronized limiter operation in the Wendelstein 7-AS stellarator. Netherlands.
Brakel, R, Burhenn, R, Behrisch, R, Grigull, P, Hacker, H, Hildebrandt, D, Hofmann, J V, Mahn, C, Roth, J, Schneider, U, Weller, A, Hirooka, Y, W7-AS Team, NI Group, and ECRH Group. 1992. "Bulk-boronized limiter operation in the Wendelstein 7-AS stellarator." Netherlands.
@misc{etde_6705703,
title = {Bulk-boronized limiter operation in the Wendelstein 7-AS stellarator}
author = {Brakel, R, Burhenn, R, Behrisch, R, Grigull, P, Hacker, H, Hildebrandt, D, Hofmann, J V, Mahn, C, Roth, J, Schneider, U, Weller, A, Hirooka, Y, W7-AS Team, NI Group, and ECRH Group}
abstractNote = {Bulk-boronized graphite (20% boron) has been tested as a limiter material in the Wendelstein 7-AS stellarator. The recycling behaviour and the plasma impurities are compared for the new material and the formerly used TiC-coated graphite with stainless steel and boronized walls. After conditioning the recycling and the oxygen and carbon levels are comparable for both materials. No significant impact of sputter boronization from the limiters on the oxygen level was observed. A drastical reduction of oxygen by about a factor of 10 was obtained only after additional gas boronization. In this case Z[sub eff] is primarily determined by carbon and boron. For ECF standard discharges Z[sub eff][approx equal]2 with P[sub rad]=6% of the input power was found as compared to Z[sub eff]< or approx.3 and P[sub rad]=10% before boronization and Z[sub eff][approx equal]4, P[sub rad]=20% with TiC-limiters. (orig.).}
journal = {Journal of Nuclear Materials (Journal des Materiaux Nucleaires); (Netherlands)}
place = {Netherlands}
year = {1992}
month = {Dec}
}