Deuterium removal during thermo-oxidation of Be-containing codeposits from JET divertor tiles

C. K. Tsui, A. A. Haasz (Corresponding Author), J. W. Davis, J. P. Coad, Jari Likonen

Research output: Contribution to journalArticleScientificpeer-review

20 Citations (Scopus)

Abstract

This study focuses on the removal of trapped D from thick codeposits on JET divertor tiles via thermo-oxidation. The tiles were removed from the JET Mark II Gas Box divertor after the 1998–2001 campaign. These codeposits have Be concentrations of up to ~60% Be/(Be + C) and their thicknesses range from 10 to 270 µm. Laser thermal desorption spectroscopy was used to determine the D removal rates and final remaining D concentrations following oxidation. Estimates of the carbon removed during oxidation were obtained from mass-loss measurements. The initial rate of D removal was found to be much higher for the thick codeposits of this study than for the previously studied codeposits with thicknesses in the range 1–5 µm (from TFTR, DIII-D and JET). This is despite the large Be concentrations. For oxidation performed at 623 K (350 °C) and 21 kPa (160 Torr) O2 pressure the initial D removal rates were found to increase linearly with increasing 'inherent' D content; about 50% of the inherent D was removed from all specimens in the first 15 min—independent of Be content and codeposit thickness. Following 8 h of oxidation, the fraction of D removed was >85% for all specimens, again, independent of Be content and thickness.
Original languageEnglish
Article number035008
Number of pages9
JournalNuclear Fusion
Volume48
Issue number3
DOIs
Publication statusPublished - 2008
MoE publication typeA1 Journal article-refereed

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tiles
deuterium
oxidation
boxes
desorption
carbon
estimates
gases
spectroscopy
lasers

Keywords

  • JET
  • divertor plasma
  • divertor tiles
  • fusion energy
  • fusion reactors
  • plasma
  • oxidation

Cite this

Tsui, C. K. ; Haasz, A. A. ; Davis, J. W. ; Coad, J. P. ; Likonen, Jari. / Deuterium removal during thermo-oxidation of Be-containing codeposits from JET divertor tiles. In: Nuclear Fusion. 2008 ; Vol. 48, No. 3.
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abstract = "This study focuses on the removal of trapped D from thick codeposits on JET divertor tiles via thermo-oxidation. The tiles were removed from the JET Mark II Gas Box divertor after the 1998–2001 campaign. These codeposits have Be concentrations of up to ~60{\%} Be/(Be + C) and their thicknesses range from 10 to 270 µm. Laser thermal desorption spectroscopy was used to determine the D removal rates and final remaining D concentrations following oxidation. Estimates of the carbon removed during oxidation were obtained from mass-loss measurements. The initial rate of D removal was found to be much higher for the thick codeposits of this study than for the previously studied codeposits with thicknesses in the range 1–5 µm (from TFTR, DIII-D and JET). This is despite the large Be concentrations. For oxidation performed at 623 K (350 °C) and 21 kPa (160 Torr) O2 pressure the initial D removal rates were found to increase linearly with increasing 'inherent' D content; about 50{\%} of the inherent D was removed from all specimens in the first 15 min—independent of Be content and codeposit thickness. Following 8 h of oxidation, the fraction of D removed was >85{\%} for all specimens, again, independent of Be content and thickness.",
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Deuterium removal during thermo-oxidation of Be-containing codeposits from JET divertor tiles. / Tsui, C. K.; Haasz, A. A. (Corresponding Author); Davis, J. W.; Coad, J. P.; Likonen, Jari.

In: Nuclear Fusion, Vol. 48, No. 3, 035008, 2008.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Deuterium removal during thermo-oxidation of Be-containing codeposits from JET divertor tiles

AU - Tsui, C. K.

AU - Haasz, A. A.

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AU - Coad, J. P.

AU - Likonen, Jari

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N2 - This study focuses on the removal of trapped D from thick codeposits on JET divertor tiles via thermo-oxidation. The tiles were removed from the JET Mark II Gas Box divertor after the 1998–2001 campaign. These codeposits have Be concentrations of up to ~60% Be/(Be + C) and their thicknesses range from 10 to 270 µm. Laser thermal desorption spectroscopy was used to determine the D removal rates and final remaining D concentrations following oxidation. Estimates of the carbon removed during oxidation were obtained from mass-loss measurements. The initial rate of D removal was found to be much higher for the thick codeposits of this study than for the previously studied codeposits with thicknesses in the range 1–5 µm (from TFTR, DIII-D and JET). This is despite the large Be concentrations. For oxidation performed at 623 K (350 °C) and 21 kPa (160 Torr) O2 pressure the initial D removal rates were found to increase linearly with increasing 'inherent' D content; about 50% of the inherent D was removed from all specimens in the first 15 min—independent of Be content and codeposit thickness. Following 8 h of oxidation, the fraction of D removed was >85% for all specimens, again, independent of Be content and thickness.

AB - This study focuses on the removal of trapped D from thick codeposits on JET divertor tiles via thermo-oxidation. The tiles were removed from the JET Mark II Gas Box divertor after the 1998–2001 campaign. These codeposits have Be concentrations of up to ~60% Be/(Be + C) and their thicknesses range from 10 to 270 µm. Laser thermal desorption spectroscopy was used to determine the D removal rates and final remaining D concentrations following oxidation. Estimates of the carbon removed during oxidation were obtained from mass-loss measurements. The initial rate of D removal was found to be much higher for the thick codeposits of this study than for the previously studied codeposits with thicknesses in the range 1–5 µm (from TFTR, DIII-D and JET). This is despite the large Be concentrations. For oxidation performed at 623 K (350 °C) and 21 kPa (160 Torr) O2 pressure the initial D removal rates were found to increase linearly with increasing 'inherent' D content; about 50% of the inherent D was removed from all specimens in the first 15 min—independent of Be content and codeposit thickness. Following 8 h of oxidation, the fraction of D removed was >85% for all specimens, again, independent of Be content and thickness.

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KW - divertor tiles

KW - fusion energy

KW - fusion reactors

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JF - Nuclear Fusion

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