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					                           WP10-PWI-01-02-01(02)/TEKES/BS(PS)
                           Characterization of retention
                           mechanisms in AUG
                           Monitoring meeting of the EFDA PWI SEWG on Gas
                           Balance and Fuel Retention, 19-20 July, 2010

                           Antti Hakola
                           VTT Technical Research Centre of Finland
Collaborators:
S. Koivuranta, J. Likonen: VTT
T. Haikola, J. Kolehmainen, S. Tervakangas: DIARC-Technology Inc.
K. Krieger, M. Mayer, R. Neu, V. Rohde, K. Sugiyama: IPP-Garching
                                                                   20/07/2010   2




                           What was proposed?

• analyze a set of marker tiles, exposed to AUG plasma during the 2009
  experimental campaign, and study retention of deuterium in them
     Secondary Ion Mass Spectrometry (SIMS) analyses at VTT in Finland
     Nuclear Reaction Analyses (NRA) at IPP-Garching
• produce new marker tiles for erosion, deposition, and retention studies in AUG
                                                                        20/07/2010      3




               Marker tiles for the 2009 AUG campaign
• inner and outer strike-point tiles (4, 4B, and 1)
• two different 3B tiles; one of them magnetically connected
  to an ICRH source
• tiles had 15-mm wide uncoated stripes, tiles 1 and 3B
  also 15-mm wide and 2-5 mm thick Ni stripes, and 1-1.5                             Ni, 2 mm
  mm thick W coating                                                   C
                                                                   W, 1 mm

                                                                                       2 × tile 3B

       15 mm                                                   W
                                                               1.5 mm
  W
  1 mm C                                                            C
                                                                        Ni
                                                                        5 mm



                                C W, 1 mm
    Tile 4            Tile 4B
                                                                   Tile 1
                                                                    20/07/2010   4




              What was done: SIMS and NRA analyses
• NRA analyses performed in March 2010 at IPP Garching
     2.5-MeV 3He+ ions used
     measurements done at 5-10 mm steps along each marker stripe
• SIMS analyses done in April-May 2010 at VTT, Finland
     samples drilled from each tile for analyses
     5-keV O2+ ions used
     measurement points at 20-30 mm steps along each marker stripe
     results converted to quantitative ones with the help of the NRA data




                                                                       Photograph of tile 1
                                                                       before and after drilling
                                                                       SIMS samples
                                                                                                                                        20/07/2010      5




                                      Results (1): SIMS depth profiles of D on W

                                        Tile 4, s = 494 mm                   H                                                                                     H
                                                                                                                            Tile 1, s = 1162 mm
                  100000                                                     D                        100000                                                       D
                                                                             10                                                                                    10
                                                                               B                                                                                      B
                                                                             12                                                                                    12
                                                                               C                                                                                      C
                   10000                                                     13                        10000                                                       13
                                                                               C                                                                                      C
                                                                             52                                                                                    52
                                                                               Cr                                                                                     Cr
Intensity (1/s)




                                                                                    Intensity (1/s)
                    1000                                                     60
                                                                               Ni                       1000                                                       60
                                                                                                                                                                      Ni
                                                                             184
                                                                                W                                                                                  184
                                                                                                                                                                       W
                     100                                                                                 100


                     10                                                                                   10


                      1                                                                                    1
                           0   1000   2000   3000       4000   5000   6000                                     0   1000   2000   3000   4000     5000       6000
                                             Time (s)                                                                             Time (s)

                     Below inner strike point (deposition                                                Above outer strike point (erosion
                     zone in the private flux region)                                                    zone)
                     Sputtering rate approximately 0.3-0.4 nm/s
                      largest retention in < 500-nm thick layer
                                                                                                    20/07/2010   6




                                                             Results (2): D on W
                        7.0E+18
                                        Tile 4
                        6.5E+18
                        6.0E+18
                        5.5E+18
                        5.0E+18
Amount of D in at/cm2




                        4.5E+18                                                                                      NRA (tile 4)
                        4.0E+18                                                                                      NRA (tile 1)
                                                                                                                     NRA (tile 3B-I)
                        3.5E+18
                                                                                                                     NRA (tile 3B-II)
                        3.0E+18
                                                                                                                     SIMS (tile 4)
                        2.5E+18                                                                                      SIMS (tile 1)
                        2.0E+18                                                                                      SIMS (tile 3B-I)

                        1.5E+18                                                                                      SIMS (tile 3B-II)
                                                                        Tile 1                 Tiles 3B
                        1.0E+18
                        5.0E+17
                        0.0E+00
                                  350            550   750     950       1150    1350   1550       1750
                                                                     s (mm)
                                                                                                         20/07/2010   7




                                                             Results (3): D on C
                        1.2E+19
                                        Tile 4
                        1.1E+19

                        1.0E+19

                        9.0E+18
Amount of D in at/cm2




                        8.0E+18
                                                                                                                      NRA (tile 4)
                        7.0E+18                                                                                       NRA (tile 1)
                                                                                                                      NRA (tile 3B-I)
                        6.0E+18
                                                                                                                      NRA (tile 3B-II)
                        5.0E+18                                                                                       SIMS (tile 4)

                        4.0E+18                                                                                       SIMS (tile 1)
                                                                                                                      SIMS (tile 3B-I)
                        3.0E+18                                                                                       SIMS (tile 3B-II)
                        2.0E+18                                      Tile 1                   Tiles 3B
                        1.0E+18

                        0.0E+00
                                  350            550   750     950            1150   1350   1550     1750
                                                                     s (mm)
                                                                                                     20/07/2010   8




                                                             Results (4): D on Ni
                        4.0E+18


                        3.5E+18


                        3.0E+18
Amount of D in at/cm2




                        2.5E+18
                                                                                                                  NRA (tile 1)
                                                                                                                  NRA (tile 3B-I)
                        2.0E+18
                                                                                                                  NRA (tile 3B-II)
                                                                                                                  SIMS (tile 1)
                        1.5E+18
                                                                                                                  SIMS (tile 3B-I)
                                             Tile 1
                                                                                                                  SIMS (tile 3B-II)
                        1.0E+18
                                                                                       Tiles 3B
                        5.0E+17


                        0.0E+00
                               1000   1100            1200   1300       1400   1500   1600    1700    1800
                                                                    s (mm)
                                                                                                                             20/07/2010   9




                          Comparison between different substrates: tile 1

                         Tile 1, D amount, NRA                                                     Tile 1, D amount, SIMS
                                                                                       9E+17
             9E+17
                                                                                       8E+17
             8E+17
                                                                                       7E+17
             7E+17
                                                                                       6E+17




                                                                          D (at/cm2)
             6E+17
D (at/cm2)




                                                                                       5E+17
             5E+17                                                                                                                               W
                                                                     W                 4E+17
             4E+17                                                                                                                               C
                                                                     C                 3E+17
             3E+17
                                                                                       2E+17                                                     Ni
             2E+17                                                   Ni
                                                                                       1E+17
             1E+17
                                                                                           0
                 0
                                                                                            1000    1050   1100    1150    1200    1250   1300
                  1000   1050   1100    1150    1200   1250   1300
                                                                                                                  s (mm)
                                       s (mm)


    • deuterium peaks below the outer strike point in the private flux region and on a
      thin stripe in the middle of the tile (resulted from an injection experiment)
    • clear differences between the different materials: retention largest in carbon
      (graphite)
    • Ni stripe complicated: stripe heavily eroded between 1060 and 1160 mm (strike-
      point region)
              NRA results in this region not reliable, SIMS results cannot be evaluated at all
                                                                                                         20/07/2010         10




                              Comparison between different substrates: tile 4

                             Tile 4, D amount, NRA                                          Tile 4, D amount, SIMS
             1.2E+19                                                        1.2E+19
              1E+19                                                          1E+19
              8E+18
D (at/cm2)




                                                                             8E+18




                                                               D (at/cm2)
              6E+18                                                          6E+18
                                                           W                                                                           W
              4E+18                                        C                 4E+18                                                     C
              2E+18                                                          2E+18
                  0                                                              0
                       350      400    450     500   550                              350       400    450            500        550
                                      s (mm)                                                          s (mm)

   • deuterium peaks below the inner strike point in the border region between tiles 4
     and 4B (private flux region)
   • again carbon is responsible for larger D inventories than tungsten; notice that
     the values are order of magnitude higher than in tile 1
   • SIMS results do not show as prominent peaks as NRA, particularly in the case of C
              lack of data points in the critical region but impossible to obtain samples for
               SIMS analyses in that region.
                                                                                                                   20/07/2010   11




                       Comparison between different substrates: tiles 3B
                      Tile 3B, D amount, NRA                                                 Tile 3B, D amount, SIMS
             8E+17                                                                   8E+17
             7E+17                                                                   7E+17
             6E+17                                                                   6E+17
                                                            W, 3B-I                                                                  W, 3B-I
D (at/cm2)




                                                                        D (at/cm2)
             5E+17                                                                   5E+17
                                                            W, 3B-II                                                                 W, 3B-II
             4E+17                                                                   4E+17
                                                            C, 3B-I                                                                  C, 3B-I
             3E+17                                                                   3E+17
                                                            C, 3B-II                                                                 C, 3B-II
             2E+17                                                                   2E+17
                                                            Ni, 3B-I                                                                 Ni, 3B-I
             1E+17                                                                   1E+17
                 0                                          Ni, 3B-II                                                                Ni, 3B-II
                                                                                         0
                  1580 1600 1620 1640 1660 1680 1700 1720                                 1580 1600 1620 1640 1660 1680 1700 1720
                                  s (mm)                                                                  s (mm)


        • retention largest on graphite and lowest on Ni
        • tile 3B-II (magnetically connected to an ICRH source) shows somewhat larger D
          inventories than tile 3B-I (no magnetic connection
                                                                                                                                           20/07/2010     12




                                     Evolution of D inventory on W (2007-2009)
                             Tile 1, D on W, NRA                                                                         Tile 4, D on W, NRA
                                                                           VPS tiles                                                                           PVD tile
               2E+18
                                                                           2007 & 2008                    7E+18
                                                                                                                                                               2007
             1.8E+18
             1.6E+18                                                       Marker tile                    6E+18                                                Marker tiles
             1.4E+18                                                       2009                           5E+18                                                2008 & 2009
D (at/cm2)




             1.2E+18




                                                                                             D (at/cm2)
               1E+18                                                            2007                      4E+18                                                   2007
               8E+17                                                            2008                      3E+18                                                   2008, set#1
               6E+17
                                                                                2009                                                                              2008, set#2
               4E+17                                                                                      2E+18
               2E+17                                                                                                                                              2009
                                                                                                          1E+18
                   0
                    1000      1050    1100    1150    1200   1250   1300                                      0
                                             s (mm)                                                               300   350   400    450     500        550
                                                                                                                                s (mm)
                              Tile 3B, D on W, NRA                         PVD tile
                                                                           2007
                    4E+17                                                                                 • tile 1: retention decreased by a factor
                   3.5E+17                                                 Marker tiles
                    3E+17                                                  2008 & 2009                      of 2-10 from 2007 to 2009
                                                                                                          BUT change from VPS tiles to other
      D (at/cm2)




                   2.5E+17                                                     2007
                    2E+17                                                      2008, set#1
                                                                                                          coatings
                   1.5E+17                                                     2008, set#2
                    1E+17                                                      2009, 3B-I
                                                                                                          • tile 4/4B: thicker co-deposited layers
                    5E+16                                                      2009, 3B-II
                        0                                                                                   below the inner strike point in 2009 than
                         1580 1600 1620 1640 1660 1680 1700 1720                                            in 2007 or 2008
                                             s (mm)
                                                                   20/07/2010   13




               New marker tiles for 2010 AUG campaign

                                                                  Korund, Ra = 5.5 mm
                                                                  Glas, Ra = 0.75 mm
                                                                  Original, Ra = 0.38 mm


                                                                  Korund, Ra = 6.4 mm
                                                                  Glas, Ra = 3.9 mm
                                                                  Original, Ra = 2.7 mm

                      W 2 mm                            Mo 2 mm

    Tile 1: poloidal regions with different surface roughness

    W 3 mm
                                       W + 5% Ta 3 mm
       Mo 3 mm
              Cr 3 mm
                                                        W 3 mm
                     Al 4 mm


    Tile 1: poloidal stripes for erosion/deposition studies
Coating half of these tiles belongs to task WP10-PWI-01-02-02/TEKES/PS
                                                                   20/07/2010   14




                                  Conclusions

• marker tiles exposed to AUG plasma during the 2009 experimental campaign
  analyzed using SIMS and NRA
• retention of deuterium in the tiles has been determined:
      largest retention in graphite, lowest in nickel
      deuterium accumulated in deposition-dominated regions of the divertor
         together with carbon and boron
      tile 3B with magnetic connection to an ICRH antenna shows more D than
         the tile 3B without such a connection
• new marker tiles for erosion, deposition, and retention studies in AUG have been
  produced

				
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