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Mem
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of
the H
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Institute of Energy Research – Plasma Physics | Association EURATOM – FZJA. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Investigations of fuel accumulation and material transport into gaps of ITER-like
castellated structures
A. Litnovsky, M. Freisinger, V. Philipps, P. Wienhold, H.-G. Esser,
S. Brezinsek, D. Rudakov, S. Allen, T. Dittmar, E. Tsitrone B. Pequourie,
TEXTOR, Tore Supra and DIII-D teamsProgress reports on the task: WP10-PWI-01-02-02/FZJ/BS
Slide 2 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
TDS measurements on Tore Supra tiles:
a part of DITS project
TORE SUPRA
Please see the talk of E. Tsitrone for an overview of entire DITS project
Slide 3 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
TDS measurements on DITS samples TORE SUPRA
Samples from different areas of TPL:
Erosion zone;
Zone with thick deposits;
Zone with thin deposits.
Several samples with flakes;
13 samples measured, 6 samples are to be outgased.
In the frame of the DITS project, several graphite
samples from Tore Supra toroidal limiter (TPL)
delivered to FZJ for the TDS measurements
Slide 4 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
TDS facility at FZJ: overview
Main parameters:
Sample dimensions: maximum 55 mm;
Maximum temperature: 1150oC (oven can go up to
1200oC);
Separate vacuum evacuation of sample
chamber;
Programmable temperature increase: unlimited time (can
be days);
Sample weight: samples up to 200 g are OK;
Temperature control: thermocouple in the oven (if necessary – may be installed
in the sample);
Calibration technique: calibration leaks.
Slide 5 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
TDS facility at FZJ: main components
Sample mounting and transport system
Oven
Slide 6 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
1.4E18
7.8E17
1E20
1.85E18
1.34E18
3.06E187.13E19
2.03E19
3.87E20
6.61E18
2.54E20
X
bulk
top flakes
to be done
Preliminary TDS results: cartography
Color legend:
6.3E181.39E18
bulktop
Thin deposits*
Thick deposits*
* B. Pequourie, PSI 18 Toledo, Spain, May 2008 + J. Nucl. Mater., 390–391 (2009) 550
Erosion zone*
TORE SUPRA
Approximate dimensions of samples: 25×25×3 mm
Standard samples were supplied by W. Jacob (IPP Garching)
Slide 7 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Preliminary first TDS results: trends
Erosion zone Thin deposits
Thick deposits Fuel accumulation in flakes
Fuel inventory (absolute): Dtops/Dbulk~70;
Dtops/C~ 0.04-0.6%
Almost no D.
High temperature
Fuel inventory (absolute): Dtops/Dbulk~3;
Dtops/C~ 0.01-0.04%
Almost no D
Measurements are in progress
Fuel inventory (absolute): Dflakes/Dbulk~0.1;
Dflakes/C~ 40-80%
Highest fuel inventory so far
Lowest temperature
No firm results yet
TORE SUPRA
Slide 8 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Exposure of ITER-like castellated structures in the DIII-D divertor
Slide 9 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Exposure on DiMES manipulator at the
level of divertor floor; Exposure in PFR; Non-heated sample;
Exposure 1 (2008):
8 identical NBI-heated discharges with
partially detached plasmas in the divertor;
Exposure 2 (2009):
3 days in piggyback mode;
Scheme of exposure
Castellated DiMES
Strong and optimized shaping
0.2 mm 1.0 mm
A B
Castellation blocks (W)
Exposure of castellation in DIII-D divertor
View of castellation after
exposure
Slide 10 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Exposure 2 Strong deposition both on toroidal and poloidal gaps:
deposits with thickness of up to 250 nm were
detected in the gaps according to SIMS and
colorimetry; Carbidization of tungsten at the interface between
deposit and substrate (SIMS); Small or negligible metal mixing in the deposit layers
both in poloidal and toroidal gaps: results from
EPMA and SIMS. Strong asymmetry in the deposition in toroidal gaps:
full similarity with TEXTOR results.
Exposure of castellation in DIII-D divertor: current results
Slide 11 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Fuel removal castellated structures: O-bake experiment in DIII-D
Slide 12 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
O-bake experiment in DIII-D: general information
Demonstrate an oxygen bake on the DIII-D tokamak and recover high performance plasma operation (with only clean vents)
Demonstrate removal from several tiles with a second oxygen bake
Goals:
O-bake experiments 2010: 2 hours; 20% O + 80% He; 13 mbar; 350oC; 1st experiment: 13.04.2010, 2nd experiment: 27.04.2010 (with castellation)DiMES
(castellation at 350oC)
Tile shelf with samples(350oC->160oC)
Slide 13 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
O-bake experiment in DIII-D: exposure of castellation
Tungsten ITER-like castellation was exposed in the DIII-D divertor during 2nd O-bake exposure Poloidal gaps were coated a-C:D film prior to O-bake; a:-C-D film was pre-characterized via identical witness sample
Details:Castellated DiMES sample
Pre-coated poloidal gaps
First impression: exposure did not change much
before after
Next steps-analyses in the gaps: EPMA, NRA, SIMS/DEKTAK
4.5*1017 C/cm2
(EPMA)~ 70 nm
Slide 14 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Castellated limiter IV for TEXTOR
Slide 15 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Castellated limiter IV:castellation at different angles to B field
Critical region: the edges must be at the same height and position
Features
3 angles: 3o, 10o, 20o
Rectangular and moderately
shaped geometries of cells
Activities 2010: Castellation manufacturing: done;
Holder manufacturing: in progress;
Thermal simulation of castellation: in progress.
Miranda van den Berg, Gregory De Temmerman (TEC, FOM)
Slide 16 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Finalizing TDS measurements;
Analyses of data and providing an input to DITS.
TDS measurements on DITS samplesPlans 2010:
Investigations of fuel accumulation and material transport into gaps of ITER-like
castellated structures WP10-PWI-01-02-02/FZJ/BS
Analyses are underway on the castellated samples exposed
in Tore Supra and DIII-D tokamaks.
The effectiveness of deposit and fuel removal from
castellated structures using O-bake technique in DIII-D is
being studied.
Slide 17 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Finalizing surface analyses of deposits;
Analyses of all the data from all gaps;
Recommendations on castellation shaping.
Comparison of TEXTOR and DIII-D results.
Plans 2010 (continued):
Finalizing the thermal loads simulation and holder
manufacturing;
Exposure in TEXTOR.
Castellated limiter IV (TEXTOR)
Analyses of deposits and fuel distribution in the gaps;
Assessment of the O-bake effectiveness in DIII-D.
O-bake experiment in DIII-D
Castellation exposures in DIII-D
Slide 18 of 18
A. Litnovsky et al., Progress report on the task WP10-PWI-01-02-02/FZJ/BS, EU TF PWI SEWG on fuel retention, Garching, July 19-20, 2010.
Thank you