1E. Tsitrone20th IAEA Vilamoura 1-6/11/2004 Euratom Deuterium retention in Tore Supra long...
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Transcript of 1E. Tsitrone20th IAEA Vilamoura 1-6/11/2004 Euratom Deuterium retention in Tore Supra long...
1E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomDeuterium retention in Tore Supra long discharges
• Interpreting the particle balance
• Particle retention during long discharges
• Particle recovery (after shot, glows, disruptions)
• Experimental results
E. Tsitrone, C. Brosset, J. Bucalossi, B. Pégourié, T. Loarer, P. Roubin2, Y. Corre, E. Dufour, A. Géraud, C. Grisolia , A. Grosman, J. Gunn , J. Hogan3 , C. Lowry, R. Mitteau , V. Philips4,
D. Reiter4, J. Roth5, M. Rubel6, R. Schneider7, M. Warrier7
Association Euratom-CEA, CEA Cadarache, CEA-DSM-DRFC, F-13108 Saint Paul-lez-Durance, France2 : LPIIM, UMR 6633, Université de Provence, Centre Saint-Jérôme13 397 Marseille cedex 203 : Fusion Energy Division, ORNL, Oak Ridge, TN 37831-8072 USA4 : Institut für Plasmaphysik, FZ Jülich, Euratom Association, D-52425 Jülich, Germany5 : Max Planck Institute für Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching Germany6 : Alfven Laboratory, Royal Institute of Technology, Association Euratom VR, 100 44 Stockholm, Sweden7 : Max Planck Institute für Plasmaphysik, Euratom Association, Teilinst. Greifswald, Wendelsteinstrasse 1, D-17491 Greifswald Germany
2E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomTore Supra : the CIEL configuration
• Long pulse : LH driven discharge at Vloop ~ 0, low plasma current/density low density hot edge plasma (Te ~ 100 eV at the LCFS)
Toroidal pump limiter (TPL)
Bumpers
Outboard movable limiter
• 15 m2 of carbon plasma facing components• Active cooling : stationary PFC temperaturefrom 120°C (cooling loop) up to 250°C on the limiter for long pulses
Plasma loaded zones
Shadowed zones
CCD imaging of the TPL
• Active pumping : neutralisers below TPL
3E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
Phase 1 Phase 2
Particle retention in long discharges
No saturation of in vessel retention after 15 minutes of cumulated plasma time
• Phase 2Constant retention rate (= 50% of injected flux)No saturation after 6 minutes
• Identical shot to shot behaviour
• Phase 1 (~ 100 s)Decreasing retention rate
• In vessel inventory shot duration in phase 2(Imax = 8 1022 D for 6 minutes)
4E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
Phase 1 Phase 2
Retention phase 1
x 1021
Particle recovery after shot
• Recovery > plasma content : the wall releases particles
x 1022
• Recovery correlated to retention in phase 1 : transient retention mechanism
• Small fraction recovered after shot
~ 100 s
5E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomParticle recovery after glow discharge and disruptions
Recovery after He glow discharge (6 hours) : 1.5 - 2 1022 D < Imax
• Independent of the quantity trapped during the day of experiment
0.2 0.4 0.6 0.8 1 1.2 1.4 1.60
20
40
60
80
100
120
Plasma current before disruption (MA)
Par
ticle
exh
aust
(P
a.m
3)
Tore Supra - Disruptions 2002-2004
0.2 0.4 0.6 0.8 1 1.2 1.4 1.60.2 0.4 0.6 0.8 1 1.2 1.4 1.60
20
40
60
80
100
120
0
20
40
60
80
100
120
Plasma current before disruption (MA)
Par
ticle
exh
aust
(P
a.m
3)
Tore Supra - Disruptions 2002-2004
Recovery after disruption : up to 5 1022 D < Imax
• Large scatter at given Ip : machine history dependent ?(highest exhaust in start up phase)
• Threshold in Ip :
• Ip < 0.8 MA : ~ after shot recovery• Ip > 0.8 MA : increase with Ip dissipated energy high enough to heat D rich deposited layers [D. Whyte, PSI 2004]
6E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomSample analysis : D content
Outboard limiter
Cold deposits (~ 120 °C)D/C ~ 10 %ND ~ 1022 at /m2 / m * S * d
TPL
Neutraliser finger
Hot deposits (> 500°C)D/C ~ 1 %ND ~ 1021 at/m2 * S
[C. Brosset, PSI 2004]
TPL deposits analysis still in progressCold deposits in shadowed areas D reservoir
Several ms
Shadowed
< 1 m
Plasma facing
Several ms
Carbon deposits
Net deposition zoneNet erosion zone (main plasma interaction area)
Net deposition zones
7E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomInterpreting the particle balance
BUT : does not explain shot to shot behaviour unless very strong diffusion takes place
Phase 1
Progressive saturation of bombarded surfaces (D+, D0) until CDmax reached
• Implantation D C D+, D0
dimp< 0.1 m
Carbon
D+
D0
D2+
D2
TPL
Bumpers
[E. Tsitrone, PSI 2004]
Saturation time : from ~ 1s (TPL) to ~ 100 s (bumpers)
8E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
Phase 1
Interpreting the particle balance
• Outgassing after shot ~ phase 1 duration ( ~ 100s) : ok with filling / emptying the porosity reservoir
Good candidate for phase 1 BUT : extrapolation from lab to tokamak environment (temperature)
• TS deposited layers : 100 times more porous than original CFC [P. Roubin, PSI 2004]
• Filling the CFC porosityD2, D0
Adsorption
M. Warrier et al., Contrib. Plasma Phys. 44, No. 1-3, (2004)
• Adsorption : weak bond ( chemical bond) ok for transient mechanism
• Extrapolation from lab exp (77 K) : 1022 D/g deposits 0.5 g enough to account for phase 1
5 1021 D
9E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomInterpreting the particle balance
Phase 1 + 2
• ok with Zeff, ok with low net erosion on TPL (high local redeposition), ok with layers growing rate
1020 C/s1.5 1020 CD4/s
Distant redeposition (TPL shadowed areas, neutralisers, outboard limiter …)
6 1020 C/s (phys. + self)
1.5 1020 CD4/s (chem.)
Erosion
5 1020 C6+/s
Local redeposition
Preliminary estimates of carbon erosion sources • physical + chemical sputtering by D+ and D0
• self sputtering by Cn+ (assumed 5% C in D+ flux)
• Codeposition :
Carbon deposits
C, D
CxDy
physical sputtering
chemical sputtering
carbon balance roughly coherent
10E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomInterpreting the particle balance
Phase 1 + 2
• If D/C = 0.1 : need 2 1021 C/s of net redeposition : high erosion/redeposition on TPL ( > 100 m on 4 m2): not observed
No coherence between D retention rate / D/C ratio / C erosion/redeposition
D rich film created during the discharge subsequently depleted in D (glows, disruptions) ?
Hard to explain the retention rate in phase 2 with codeposition alone
• 1/3 of produced CD4 trapped : but high D/C ratio film : not observed
2 1020 D/s
1020 C/s1.5 1020 CD4/s
Distant redeposition (TPL shadowed areas, neutralisers, outboard limiter …)6 1020 C/s
1.5 1020 CD4/s
Erosion
5 1020 C6+/s
Local redeposition
• Codeposition : D balance
11E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom Summary
Phase 2Phase 1
• D implantation in C : progressive saturation but not transient
• D adsorption in porosity : good candidate, but to be assessed in tokamak environment
• Codeposition of D and C :Can hardly explain the retention rate in phase 2
• D content sample analysis : D mainly in cold deposits in shadowed areas (120 °C)
Missing D not found yet but still a lot to investigate (TPL deposits, pumping ducts …)
• D recovery (He glow discharge, disruptions) < in vessel inventory accumulated in a single long discharge
• D retention : no wall saturation after 15 minutes in high Te / low ne edge plasma
Transient retention : recovered after shot
Permanent retention : NOT recovered after shot
12E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
13E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomTore Supra : well equipped for particle balance
• Gas injection : manometers
• Active pumping : 10 neutralisers with turbo-molecular pumps equipped with 20 pressure gauges (1 in vertical port, 1 at the pump) + 2 Penning gauges (D2/He) + mass spectrometer• 2 pressure gauges in the chamber (equatorial ports)• pressure gauges in primary exhaust system
• Systematic calibration procedure : calibrated gas injection in the chamber with/without pumps activated
D+
to pumps
dNp/dt = inj – pump – in vessel
14E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomEffect of active pumping
Pumping on
Active pumping on Tore Supra : no effect on dynamic wall retention but offset on gas injection
Pumping off
Same wall inventory
Shifted gas injection
15E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
0 50 100 150 200 250 300 350 400 450 5000
1
2
3
4
0 50 100 150 200 250 300 350 400 450 5000
50
100
150
200
250
300
350
LH power (MW)
Injected flux (Pa.m3/s)Extracted Flux (Pa.m3/s)
Gas Puffing
Vessel Inventory
TPL exhaust
Vessel ExhaustPlasma Content x100
Inve
nto
ries
(P
a.m
3 )
s
Time (s)
Shot 32299
Particle balance sensitive to LH power loss
dNp/dt = inj – pump – in vessel
16E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
Shot 33067
T (°C) before/after disruption (20 ms)
Disruption heats deposited layers
Net erosion zone (main plasma interaction area)
Thickest deposition zone (shadowed/plasma area)
Moderate deposition zone (plasma interaction area)
T > 220 °CPlasma loaded zones
Shadowed zones
CCD imaging of the TPL
17E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
T°C #33067 (t-20ms) T #33067 (disruption)
IR shows cold deposits
18E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomD inventory in the machine
Estimated D inventory in the machine : From analysed samples : ~ 5 1022 D (80% in cold deposits)From non analysed samples (TPL surface) : ~ 4 1022 D (most of it in TPL shadowed zones)Total : ~ 9 1022 D
Estimated D inventory from particle balance integrated over a campaign: From averaged net retention rates : ~ 1.5 1024 DGlow discharge : ~ 4 1023 DDisruptions : ~ 3 1023 DTotal : ~ 8 1023 D
No firm conclusion can be drawn on D balance
BUT : surface/depth of layers difficult to assess, samples still to be analysed
BUT : retention rate scenario dependent, not all disruptions recorded, glow D2 not accounted, cleaning discharges …
19E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomDeuterium retention in Tore Supra long discharges
• Interpreting the particle balance
• Particle retention during long discharges
• Particle recovery (after shot, glows, disruptions)
• Experimental results
E. Tsitrone, C. Brosset, J. Bucalossi, B. Pégourié, T. Loarer, P. Roubin2, Y. Corre, E. Dufour, A. Géraud, C. Grisolia , A. Grosman, J. Gunn , J. Hogan3 , C. Lowry, R. Mitteau , V. Philips4,
D. Reiter4, J. Roth5, M. Rubel6, R. Schneider7, M. Warrier7
Association Euratom-CEA, CEA Cadarache, CEA-DSM-DRFC, F-13108 Saint Paul-lez-Durance, France2 : LPIIM, UMR 6633, Université de Provence, Centre Saint-Jérôme13 397 Marseille cedex 203 : Fusion Energy Division, ORNL, Oak Ridge, TN 37831-8072 USA4 : Institut für Plasmaphysik, FZ Jülich, Euratom Association, D-52425 Jülich, Germany5 : Max Planck Institute für Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching Germany6 : Alfven Laboratory, Royal Institute of Technology, Association Euratom VR, 100 44 Stockholm, Sweden7 : Max Planck Institute für Plasmaphysik, Euratom Association, Teilinst. Greifswald, Wendelsteinstrasse 1, D-17491 Greifswald Germany
minimize the retention rate optimize the recovery techniques
ITER in vessel T inventory limit : (retention rate - recovery rate) dt < 350 g
20E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
Phase 1 Phase 2
Particle retention in long discharges
dNp/dt = inj – pump – in vessel
No saturation of in vessel retention after 15 minutes of cumulated plasma time
• Phase 2Constant retention rate (= 50% of injected flux)No saturation after 6 minutes
• Identical shot to shot behaviour
• Phase 1 (~ 100 s)Decreasing retention rate
• In vessel inventory shot duration in phase 2(Imax = 81022 D for 6 minutes)
21E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomSample analysis : D content
Outboard limiter
Cold deposits (~ 120 °C)D/C ~ 10 %ND ~ 1022 at /m2 / m * S * d
TPL
Neutraliser finger
Hot deposits (> 500°C)D/C ~ 1 %ND ~ 1021 at/m2 * S
[C. Brosset, PSI 2004]
TPL deposits analysis still in progressCold deposits in shadowed areas D reservoir
Several ms
Shadowed
< 1 m
Plasma facing
Several ms
Carbon deposits
Net deposition zone Net erosion zone (main plasma interaction area)
Moderate deposition zone (plasma interaction area)
Thickest deposition zone (shadowed area)
D content in analysed samples < D inventory over campaign
22E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomInterpreting the particle balance
Phase 1 + 2
• Codeposition :
Carbon deposits
C, D
CxDy
Physical sputtering (C/s)
Chem. sputtering (CD4/s)
Self sputtering (C/s)
D+ (1022 /s) 3 1020 1.25 1020 D0 (4 1021 /s) 4.5 1019 2.75 1019
C 6 + (5 1020 /s) 2.6 1020
Estimates of carbon erosion sources
• ok with Zeff, ok with high redeposition (low net erosion on TPL), ok with layers growing rate carbon balance roughly coherent 1020 C/s
1.5 1020 CD4/s
Distant redeposition (TPL shadowed areas, neutralisers, outboard limiter …)6 1020 C/s
1.5 1020 CD4/s
Erosion
5 1020 C6+/s
Local redeposition
• C source underestimated : no synergy D+/D0, no localised hot Tsurf, no LH accelerated e-
23E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomSample analysis : D content Net erosion zone
Plasma facing
< 1 m
Carbon substrate
Neutraliser finger
Outboard limiter
Cold deposits (~ 120 °C)D/C ~ 10 %ND ~ 1022 at /m2 / m * S * d
TPL
Hot deposits (> 500°C)D/C ~ 1 %ND ~ 1021 at/m2 * S
[C. Brosset, PSI 2004]
TPL deposits analysis still in progressCold deposits in shadowed areas
Several ms
Shadowed
hot deposits
cold deposits< 1 m
Plasma facing
Several ms
Carbon deposits
Net deposition zone
24E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
Euratom
Phase 1
Interpreting the particle balance
68
1019
2
4
68
1020
2
S (s
-1)
500450400350
t (s)
0.001
2
3
4
56
0.01
2
P (Pa)
68
1019
2
4
68
1020
2
S (s
-1)
500450400350
t (s)
0.001
2
3
4
56
0.01
2
P (Pa)68
1019
2
4
68
1020
2
S (s
-1)
500450400350
t (s)
0.001
2
3
4
56
0.01
2
P (Pa)
68
1019
2
4
68
1020
2
S (s
-1)
500450400350
t (s)
0.001
2
3
4
56
0.01
2
P (Pa)pvessel
Soutgas
dpvessel/dt = Soutgas – Seff pvessel
• Recovery ~ phase 1 duration : ok with filling / emptying the porosity reservoir
Good candidate for phase 1 BUT : extrapolation from lab to tokamak environment
(temperature, pressure, incident particles)
• Filling the CFC porosity
• TS deposited layers : 100 times more porous than virgin CFC [P. Roubin, PSI 2004]
D2, D0
Adsorption
M. Warrier et al., Contrib. Plasma Phys. 44, No. 1-3, (2004)
• Adsorption : weak bond ( chemical bond) ok for transient mechanism
• Extrapolation from lab exp : 1022 D/g deposits 0.5 g enough to account for phase 1
5 1021 D
25E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomDeuterium retention in Tore Supra long discharges
• Interpreting the particle balance
• Particle retention during long discharges
• Particle recovery (after shot, glows, disruptions)
• Experimental results
E. Tsitrone, C. Brosset, J. Bucalossi, B. Pégourié, T. Loarer, P. Roubin2, Y. Corre, E. Dufour, A. Géraud, C. Grisolia , A. Grosman, J. Gunn , J. Hogan3 , C. Lowry, R. Mitteau , V. Philips4,
D. Reiter4, J. Roth5, M. Rubel6, R. Schneider7, M. Warrier7
Association Euratom-CEA, CEA Cadarache, CEA-DSM-DRFC, F-13108 Saint Paul-lez-Durance, France2 : LPIIM, UMR 6633, Université de Provence, Centre Saint-Jérôme13 397 Marseille cedex 203 : Fusion Energy Division, ORNL, Oak Ridge, TN 37831-8072 USA4 : Institut für Plasmaphysik, FZ Jülich, Euratom Association, D-52425 Jülich, Germany5 : Max Planck Institute für Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching Germany6 : Alfven Laboratory, Royal Institute of Technology, Association Euratom VR, 100 44 Stockholm, Sweden7 : Max Planck Institute für Plasmaphysik, Euratom Association, Teilinst. Greifswald, Wendelsteinstrasse 1, D-17491 Greifswald Germany
minimize the retention rate optimize the recovery techniques
ITER in vessel T inventory limit : (retention rate - recovery rate) dt < 360 g
26E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomParticle recovery after glow discharge and disruptions
Recovery after He glow discharge (6 hours) : 1.5 - 2 1022 D < Imax
• Independent of the quantity trapped during the day of experiment • ~ desaturation of 15 m2 of carbon implanted with D for 300 eV incident He
0.2 0.4 0.6 0.8 1 1.2 1.4 1.60
20
40
60
80
100
120
Plasma current before disruption (MA)
Par
ticle
exh
aust
(P
a.m
3)
Tore Supra - Disruptions 2002-2004
0.2 0.4 0.6 0.8 1 1.2 1.4 1.60.2 0.4 0.6 0.8 1 1.2 1.4 1.60
20
40
60
80
100
120
0
20
40
60
80
100
120
Plasma current before disruption (MA)
Par
ticle
exh
aust
(P
a.m
3)
Tore Supra - Disruptions 2002-2004
Recovery after disruption : up to 5 1022 D < Imax
• Large scatter at given Ip : machine history dependent ?(highest exhaust in start up phase)
• Threshold in Ip :
• Ip < 0.8 MA : ~ after shot recovery• Ip > 0.8 MA : increase with Ip dissipated energy high enough to outgas deposited layers [D. Whyte, PSI 2004]
27E. Tsitrone 20th IAEA Vilamoura 1-6/11/2004
EuratomInterpreting the particle balance
BUT : does not explain shot to shot behaviour unless very strong diffusion takes place
Phase 1
Progressive saturation of bombarded surfaces (D+, D0) at CDmax = f(Einc, Tsurf )
• Implantation D C D+, D0
dimp< 0.1 m
Carbon
D+
D0
D2+
D2
TPL
Bumpers
[E. Tsitrone, PSI 2004]
Saturation time : from ~ 1s (TPL) to ~ 100 s (bumpers)
Implantation of D0 in bumpers