Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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 /IPP/BS)

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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 B / boronization) Clear reduction of C & O concentration in the plasma by boronizations A. Kallenbach et al. Nucl. Fusion 49 (2009) Aim of this study Characterization of Boron deposition on the W surface Influence of Boron on the D inventory

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July Samples and analysis procedure 6A6A 6B6B 5 4 9A9A 9B9B9C9C 9D9D A3A 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

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July A6A6B6B549A9A9B9B9C9C9D9D10123A3A3B3B 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

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

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

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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 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..?)

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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?).

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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 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?).

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July Annex

Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 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