1. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 1 Contribution of Boron on the D retention in the AUG full-W wall regime Max-Planck-Institut für Plasmaphysik K. Sugiyama, M. Mayer, V. Rohde, K. Krieger, R. Neu Max-Planck-Institut für Plasmaphysik, EURATOM Association A. Hakola, S. Koivuranta, J. Likonen VTT Technical Research Centre of Finland, Association EURATOM-Tekes (WP10-PWI-01-01-02/IPP/BS)

2. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 2 Introduction Internal view of AUG Operation with full-W wall since 2007 No boronization in 2007: extensive wall cleaning was done before the campaign to minimize the residual B in the vessel Regular boronization comes back since 2008: 5 boronizations in 2008 and 3 boronizations in 2009 campaign (~ 3.3 x 10 23 B / boronization) Clear reduction of C & O concentration in the plasma by boronizations A. Kallenbach et al. Nucl. Fusion 49 (2009) 045007 Aim of this study Characterization of Boron deposition on the W surface Influence of Boron on the D inventory

3. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 3 Samples and analysis procedure 6A6A 6B6B 5 4 9A9A 9B9B9C9C 9D9D 10 1 2 3A3A 3B3B Analyzed tiles from the divertor Post mortem analysis Nuclear reaction analysis (NRA) using 2.5 MeV 3 He + for quantitative measurement of Boron, Carbon and Deuterium 2007: whole poloidal divertor set 2008: whole set without the roof baffle Mostly PVD-W (3~5 m) coated tiles except for the outer target which was VPS-W Total discharge time: 2620 s 2009: inner and outer target tiles Analyzed tiles were exposed to 3 out of 5 boronizations Total discharge time: 3410 s Outer target (tile 1) was replaced by CMSII-W coated tile (~ 10 m). Total discharge time: 5180 s

4. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 4 6A6A6B6B549A9A9B9B9C9C9D9D10123A3A3B3B Poloidal distribution: 2007 campaign Small amount of Boron deposition at inner private flux region D retention more correlates with C deposition NRA result from 2007 tiles: No boronization in 2007 campaign BDBD BDBD BDCBDC BDCBDC

5. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 5 Poloidal distribution: 2007 & 2008 campaigns 6B6B549A9A9B9B9C9C9D9D10123A3A3B3B6A6A 2007 2008 2007 2008 B 2008 tiles were exposed to 3 boronizations Amount of Boron deposition clearly increased than 2007 by a factor of 3 - 5. The thickest B deposition was found at private flux region

6. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 6 Poloidal distribution: 2007 & 2008 campaigns 6B6B549A9A9B9B9C9C9D9D10123A3A3B3B6A6A 2007 2008 2007 2008 B C 2008 tiles were exposed to 3 boronizations Amount of Boron deposition clearly increased than 2007 by a factor of 3 - 5. The thickest B deposition was found at private flux region B deposition pattern is similar to that of C 2007 2008 2007 2008

7. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 7 Poloidal distribution: 2007 & 2008 campaigns 6B6B549A9A9B9B9C9C9D9D10123A3A3B3B6A6A B D 2008 tiles were exposed to 3 boronizations Amount of Boron deposition clearly increased than 2007 by a factor of 3 - 5. The thickest B deposition was found at private flux region B deposition pattern is similar to that of C D retention on 2008 tiles did not change so much from 2007 tiles (influence of B is small..?)

8. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 8 Poloidal distribution: 2007 to 2009 campaigns 6B6B549A9A9B9B9C9C9D9D10123A3A3B3B6A6A B D 2009 tiles were exposed to 3 boronizations Further increase of B deposition at the private flux region (note that 2009 tiles were employed longer time (5180 s) than usual (~ 3000 s) D retention at the private flux region shows also increase (because of the codeposition with B?).

9. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 9 Depth profiles of B and D SIMS profiles of D and B on 2009 tiles measured at VTT Depth profiles of B and D show sometimes nice correlation, but sometimes not... B D 12 C W B D W s = 0.44 ms = 0.49 m

10. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 10 Evolution of B deposition and D inventory Inner Divertor target: tile 4 Outer Divertor target: tile 1 Increase of D retention in the boronization phase was not as much as the increase of B deposition. At the moment, contribution of B to D retention seems to be limited. VPS-W CMSII-W

11. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 11 B deposition on 2009 marker stripes Deposition efficiency depends on the substrate material: the efficiency is less on the W compared to C surface. D retention shows also substrate dependence (by A. Hakola) Influence of substrate material B on C stripe B on W stripe Inner Divertor target: tile 4

12. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 12 Summary Boron deposition on the full-W divertor Amount of B deposition on the W divertor during the regular boronization phase increased compared to the no-boronization phase by a factor of 3 - 5. B deposition distribution is similar to C deposition distribution: major deposition is found in the private flux region. Deposition efficiency has the substrate dependence: Lower deposition efficiency on the W surface than C surface. Contribution to the D inventory in AUG Contribution is limited at the moment: - increase of D retention in the boronization phase was not as much as the increase of B deposition. Codeposition of B and D can enhance D retention (some of SIMS data showed nice correlation of B and D), nevertheless, C seems to play important role for D trapping. Influence of B (on the W surface) on the D accumulation in the W bulk is not clear because AUG has only W-coatings (Do we need lab. experiment?).

13. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 13 Annex

14. Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 14 AUG divertor: Evolution of D inventory All-W machine Decrease of total D-inventory by factor 5 ~ 10 from C-dominated to all-W (by the decrease of C and B) D-inventory in outer target tile is dominated by trapping in VPS-layers. M. Mayer et al. PSI 2008