kazuyoshi sugiyama, sewg meeting on fuel retention, garching, july 20 2010 1 max-planck-institut...
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Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 1
Max-Planck-Institut für Plasmaphysik
D retention and release behaviour of Be/C/W mixed materials
K. Sugiyama, K. Krieger, J. Roth
Max-Planck-Institut für Plasmaphysik, EURATOM Association
A. Anghel, C. Porosnicu, C.P. Lungu
National Institute for Laser, Plasma and Radiation Physics of Romania, Association EURATOM-MEdC
M.J. Baldwin, R.P. Doerner
Center for Energy Research, University of California at San Diego
(WP10-PWI-01-02-03/IPP/PS, WP10-PWI-01-02-02/MEdC/PS)
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 2
Outline
Introduction
Experimental procedure
Results
Summary and Outlook
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 3
Introduction
Wall materials in ITER
• 690 m2 Be: first wall and start-up limiter modules
• 140 m2 W: divertor dome / baffle region• 55 m2 CFC: divertor strike point areas
Material mixture Tritium retention in mixed materials
Be
W
CFC
Wall baking for tritium removal in ITER
• 240 ºC: Main chamber• 350 ºC: Divertor region
Experimental approach in this task
• Preparation of ITER relevant (Be-related) mixed material samples
• Investigation of D retention and release behaviour of mixed materials
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 4
Outline
Introduction
Experimental procedure
Results
Summary and Outlook
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 5
Sample preparation
Experimental procedure
Be12W fabrication by annealing of W film on Be substrate sample at 1073K, 10 hours
Be2C fabrication by annealing of C film on Be substrate sample at 773K, 3 hours
WC fabrication by annealing of W film on graphite substrate sample at 1373K, 4 hours
• Compounds fabrication by thermal treatment of Be-W / Be-C / W-C system
• Be-W / Be-C simultaneously deposited layers
Upgrade of TVA setup for the simultaneous deposition
Depositions were successfully done with varying Be/W and Be/C ratios
Be-related depositions were prepared by Thermionic Vacuum Arc (TVA) deposition method in MEdC
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 6
Sample preparation
Experimental procedure
Be12W fabrication by annealing of W film on Be substrate sample at 1073K, 10 hours
Be2C fabrication by annealing of C film on Be substrate sample at 773K, 3 hours
WC fabrication by annealing of W film on graphite substrate sample at 1373K, 4 hours
• Compounds fabrication by thermal treatment of Be-W / Be-C / W-C system
• Be-W / Be-C simultaneously deposited layers
D implantation to prepared layers
• 200 eV D ions implantation in the High Current Ion Source in IPP-Garching
• Flux ~ 1019 D/m2, Fluences up to ~1023 D/m2
Post mortem analysis for the prepared samples
• D release behaviour analysis by Thermal Desorption Spectroscopy (TDS)
• Quantitative analysis by Nuclear Reaction Analysis using D(3He, p)4He reaction
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 7
Outline
Introduction
Experimental procedure
Results
Be-related compounds layer
W-C compound (WC) layer
Be-W simultaneously deposited layer
Be-C simultaneously deposited layer
Summary and Outlook
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 9
1012
1013
1014
1015
300 400 500 600 700 800 900
0 100 200 300 400 500 600
Des
orpt
ion
flux
[D2/c
m2 /s
]
Temperature [K]
Temperature [C]
1012
1013
1014
1015
300 400 500 600 700 800 900
0 100 200 300 400 500 600
Des
orpt
ion
flux
[D2/c
m2 /s
]
Temperature [K]
Temperature [C]
Be2C: Additional desorption stage in the high temperature range (> 400 ºC)
Be2C
Be
D desorption from Be-related compoundsD implantation to Be-related compound layers
Be: Primary desorption peak at 150-200 ºC
D fluence ~ 1023 D/m2 @ RT
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 10
1012
1013
1014
1015
0
100
200
300
400
500
600
700
800
0 1000 2000 3000 4000
Des
orpt
ion
flux
[D2/c
m2 /s
]T
em
perature [C
]
Time [s]
D release during the temperature hold at 350 ºC
Be2C
Be
The desorption flux drops down when the temperature reaches the plateau at 350 ºC.
3.125exp~
t
The desorption flux reaches almost background level during the 20 min. hold. 5-10 % of retained D additionally released during the temperature hold at 350 ºC.
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 11
1012
1013
1014
1015
300 400 500 600 700 800 900
0 100 200 300 400 500 600
Des
orpt
ion
flux
[D2/c
m2 /s
]
Temperature [K]
Temperature [C]
Be2C
Be2C: Additional desorption stage in the high temperature range (> 400 ºC)
1012
1013
1014
1015
300 400 500 600 700 800 900
0 100 200 300 400 500 600
Des
orpt
ion
flux
[D2/c
m2 /s
]
Temperature [K]
Temperature [C]
Be12W
Be12W: The primary desorption peak becomes less intense and broader
Be
D desorption from Be-related compoundsD implantation to Be-related compound layers
Be: Primary desorption peak at 150-200ºC
D fluence ~ 1023 D/m2 @ RT
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 12
300 400 500 600 700 800
0 100 200 300 400 500 600
D r
emai
ning
fra
ctio
n [%
]
Temperature [K]
Temperature [C]
0
20
40
60
80
100350ºC240ºC
Be2C
Be12WBe
D retained fraction in Be-related compounds
Be: ≈ 90 % of initially retained D is released at 350 ºC Compounds: 60-70 % of initially retained D is released at 350 ºC
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 13
1011
1012
1013
1014
300 400 500 600 700 800
0 100 200 300 400 500 600
D2 d
eso
rptio
n flu
x [D
2/cm
2 /s]
Temperature [K]
Temperature [C]
Fluence ~ 1023 D/m2 @ RT
Bulk-W
WC
D release from WC layer
300 400 500 600 700 800
0 100 200 300 400 500 600
Temperature [K]
Temperature [C]
D r
emai
ning
fra
ctio
n [%
]0
20
40
60
80
100
Bulk-W WC
240ºC 350ºC
D release from WC shows primary desorption stage at 400 - 750 K
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 14
1011
1012
1013
1014
1015
300 400 500 600 700 800
0 100 200 300 400 500 600
D2 d
eso
rptio
n flu
x [D
2/cm
2 /s]
Temperature [K]
Temperature [C]
Be
Be12W
Fluence ~ 1023 D/m2 @ RT
D release from Be-W simultaneously deposited layer
Mixing of W in Be slightly changes the D desorption behaviour. The retention amount decreases by increase of W fraction in Be.
300 400 500 600 700 800
0 100 200 300 400 500 600
Temperature [K]
Temperature [C]
D r
emai
ning
fra
ctio
n [%
]0
20
40
60
80
100
W~10 at.%
W~60 at.%
Be12W
Be
240ºC 350ºC
1011
1012
1013
1014
1015
300 400 500 600 700 800
0 100 200 300 400 500 600
D2 d
eso
rptio
n flu
x [D
2/cm
2 /s]
Temperature [K]
Temperature [C]
W~10 at.%
W~60 at.%Bulk-W
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 15
1011
1012
1013
1014
1015
300 400 500 600 700 800
0 100 200 300 400 500 600
Des
orpt
ion
flux
[D2/c
m2 /s
]
Temperature [K]
Temperature [C]
Be
Be2C
1011
1012
1013
1014
1015
300 400 500 600 700 800
0 100 200 300 400 500 600
Des
orpt
ion
flux
[D2/c
m2 /s
]
Temperature [K]
Temperature [C]
C ~ 50 at.%
C ~ 8 at.%
Fluence ~ 1023 D/m2 @ RT
D release from Be-C simultaneously deposited layer
D release behaviour totally changes in the case of C-rich mixed layer sample
300 400 500 600 700 800
0 100 200 300 400 500 600
D r
emai
ning
fra
ctio
n [%
]
Temperature [K]
Temperature [C]
0
20
40
60
80
100
240ºC
Be2CBe
C ~ 8 at.%
350ºC
C ~ 50 at.%
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 16
How will the wall baking work in ITER ?
Best performance will be expected for:・ removal from clean Be deposit・ the removal from Be-hydrogen
codeposition formed at “cool” areas
The efficiency is marginal for:
・ Be-W codeposited layer and compounds・ “ Be-rich” Be-C mixed deposition
Less efficiency for: ・ “ C-rich” (C conc. > 50 at.%) Be-C
mixed deposition・ the hot surface (temperature is >
350ºC during a discharge)
0
20
40
60
80
100
0 10 20 30 40 50 60 70 80
D r
emai
ning
fra
ctio
n at
350
C [
%]
Impurity concentration in Be [%]
W
C
Be12WBe2C
Kazuyoshi Sugiyama, SEWG meeting on Fuel retention, Garching, July 20 2010 17
Summary and Outlook
Outlook: D implantation to mixed material samples at high temperatures
- Temperature dependence of D retention in mixed material samples
Further upgrade of TVA setup for Be-W-C (ternary) simultaneous deposition
What we have done are: Mixed material sample fabrication (collaboration with MEdC)
- TVA setup successfully upgraded for the Be-W / Be-C simultaneous deposition
Investigation of D release from mixed materials for the assessment of T removal operation in ITER (wall baking at 240 ºC / 350 ºC)
Messages: D release behaviour is affected by material mixing
- Influence of C is more significant.
- T removal efficiency of 350 ºC baking decreases by material mix compared to the case of pure Be or W.