1/18 tore supra association euratom-cea b. pégourié – sewg gaz balance & fuel retention -...
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1/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Tore Supra – repetitive long discharges.Tore Supra – repetitive long discharges.
B. Pégourié, C. Brosset, E. Tsitrone, A. Beauté, S. Brémond, J. Bucalossi, S. Carpentier,Y. Corre, E. Delchambre, C. Desgranges, P. Devynck, D. Douai, G. Dunand, A. Ekedahl,
aA. Escarguel, E. Gauthier, J. P. Gunn, P. Hertout, S.-H. Hong, F. Kazarian, M. Kocan, F. Linez, aY. Marandet, A. Martinez, bM. Mayer, O. Meyer, P. Monier-Garbet, P. Moreau, P. Oddon, J.-Y. Pascal, F. Rimini, bJ. Roth, F. Saint-Laurent, F. Samaille, S. Vartanian,
aC. Arnas, E. Aréou, C. Gil, J. Lasalle, L. Manenc, aC. Martin, aM. Richou, aP. Roubin, R. Sabot
Association Euratom-CEA, CEA/DSM/DRFC, CEA Cadarache, F-13108 Saint-Paul-lès-Durancea PIIM, CNRS/Université de Provence, F-13397 Marseille
bMPI für PlasmaPhysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching
Motivation:
Fuel retention issue
Reconcile the 2 determinations of D-retention : gas balance post-mortem analysis
Bring information on the retention mechanism : co-deposition deep migration in bulk CFC
2/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
A dedicated experiment
Deuterium Inventory in Tore Supra
Load the wall in D for good knowledge of the wall inventorygoal: 12g of D, i.e. 5× pre-campaign estimation
May 23th - June 7th, 2007
Dismantle one sector (20°) of the Toroidal Pumped LimiterExtract a number of tiles (~40) for analysis + deposits…for indentifying the retention mechanisms and close the particle balance
2007/
2008
Up to now, 10 tiles analysed
outline
OPERATIONINCREASE of IN-VESSEL D-INVENTORY INTEGRATED PARTICLE BALANCE PHYSICS of RETENTIONDetailed results on sample analysis (E. Tsitrone)Diagnostic of plasma-surface interaction (E. Delchambre)
3/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
OPERATION
4/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
OP
ER
AT
ION
100
10-1
10-2
10-3
10-4
10-5
Pre
ssu
re in
th
e to
rus
(Pa)
0 50 100 150 200 250 300 350 400 Time (h) since the beginning of the campaign
10 days of operation in 3 weeks160 « identical » long discharges (between 1 and 2 minutes)5h of plasma (about a normal year of operation)
Carbonization 13C + boronization
Time schedule of the campaign
nl ~ 2.5x1019 m-2
PLH ~ ramp up 1.31.8 MWPlasma duration 80 s
nl ~ 2.5x1019 m-2
PLH ~ 2 MWPlasma duration 120 s
Plasma scenario: retention >> post-discharge recovery
5/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Disruptions due to UFOs limit plasma durationO
PE
RA
TIO
N
UFO : Increase in Prad > 20%Scenario 1 Scenario 2
39750 Discharge number 40060
6/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
OP
ER
AT
ION
~85% of disruptions associated to flake ejection
from the limiter surface
from the LH-launchers
Hot spot outgassing (impurity) MARFE & flake ejection Prad increases swith-off PLH by security disruption
No change in core & edge parameters(moderate increase in impurity content)
7/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
OP
ER
AT
ION
Deposit pattern evolves during experiment
Beginning End of 1st phase
Deposits are thermally poorly attached to CFCIncrease of deposit thickness seen as increase of surface temperature
T-TrefT-Tref
Thick deposits : private flux regionsNo plasma , but radiation + CX atoms
Competition growth / erosionPattern characteristic to each scenario
8/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
BUILDING D-INVENTORY
9/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
D-I
NV
EN
TO
RY
WI = Inj.Gas – Exh.Gas – Post.Rec
Constant D-retention rate during campaign
60x1021
50
40
30
20
10
0
QIn
j (D
)
40.1x103
40.039.939.839.7
Discharge number
6x1021
4
2
0
QP
ost (
D)
40.0x103
39.939.839.7
Discharge number
25x1021
20
15
10
5
0
QE
xh (
D)
40.1x103
40.039.939.839.7
Discharge number
Exh
Normal dischargeDisruption
30x1021
20
10
0
-10
WI (
D)
140120100806040200
Discharge duration (s)
Trapping
Outgassing
Normal discharges Disruption
Retention rate ~ 2 g/h
Total increase of in-vessel inventory ~ 11 g deuterium
10/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
During plasma operation, C is 0.01× D in the pumped gas
[H]/[D] decreases from 20% to 2% during the campaign
D-I
NV
EN
TO
RY
Global wall inventory (1)
Total correction ~ 0.4g D
11/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Background chamber pressure 6×10-5 Pa ( 50% D2)
Total exhausted ~ 0.6g D
GlobalWI ~ 10g D (3.0×1024 atoms)
Global wall inventory (2)
Global WI = WI during plasmas – exhaust during nights & week-ends
D-I
NV
EN
TO
RY
12/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
PARTICLE BALANCE - RETENTION
13/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Tile selection for analysisP
AR
TIC
LE
BA
LA
NC
E -
RE
TE
NT
ION 40 tiles to be extracted for sampling and analysis
10 tiles selected out of 40• 5 erosion zone• 2 thin deposits• 3 thick deposits
DITS CFC structure PFCs IR Detritiation
14/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
0.30
0.25
0.20
0.15
0.10
0.05
0.00
[D]/
[C]
403020100
depth (m)
Thick deposits Thin deposits Erosion zone
0.30
0.25
0.20
0.15
0.10
0.05
0.00
[D]/
[C]
403020100
depth (m)
Thick deposits Thin deposits Erosion zone
Thick deposits 500-600°C(up to 1000°C close to the tangency point)
Thin deposits 120°C
Erosion zone 200°C
Top of the tiles Poloidal gaps
Tile analysis : NRA – average [D]/[C] profilesP
AR
TIC
LE
BA
LA
NC
E -
RE
TE
NT
ION
Gaps < 400°C
15/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
PA
RT
ICL
E B
AL
AN
CE
- R
ET
EN
TIO
NTile analysis : Thermodesorption
Integrated over Toroidal Limiter surface
Total 4g Deuterium : 40% of D-loaded
Erosion zone
Thin deposits
Thick deposits
D a
tom
s d
eso
rbed
/ s
amp
le
Integrated measurement / whole D-content
Medium samples (2mm from surface) : < 5% of D-content
Results for the first 10 tiles analysed
Top samples (first 2mm)2g/m2
0.4g/m2
16/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Integrated D-inventory
Erosion zones (3.5 m²) 2.1 g 37 % in gaps (275m)
Thin deposits (3.0 m²) 1.5 g 1 % in gaps (235 m)
Thick deposits (0.5 m²) 1.1 g 8 % in gaps ( 39 m)
Total 4.7 g (18 % in gaps)to be compared with 10 g from gas balance measurements
Erosion zones 0.4 g in tiles 0.8 g in gaps
Thin deposits 1.95 g in tiles 0.05g in gaps
Thick deposits 0.6 g 0.1 g in gaps
Trapped in bulk CFC 0.4 g (~10 % total retention)Co-deposition 3.5 g (~90 % total retention)
NRA(top +lateral faces)
TDS (top)NRA (lateral)
PA
RT
ICL
E B
AL
AN
CE
- R
ET
EN
TIO
N
17/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
0 2000 4000 6000 8000 100000
2
4
6
8
10
12
14
20 mm19 mm
D r
etai
ned
[1021
D/m
2 ]
Air exposure time [h]
QD = 1.97x1021 exp(-t/442.2)+ 8.16x1021 exp(-t/22517)
where QD is the D amount (0-16 m) expressed in D/m2,
t is the storage time expressed in h
200 eV D ions CFC NB31, Tirr = 323 K, = 4x1024 D/m2
NRA (0-16 m)
20 mm
21 mm
20 mm
20 mm19 mm
6 months
~ 65 %
PA
RT
ICL
E B
AL
AN
CE
- R
ET
EN
TIO
ND-inventory : effect of time
Decrease of the D-content between end of operation and analysis
Estimated TPL D-inventory at the end of plasma operation~7.2 g if CFC and deposits concerned (70 % of total)~5.4 g if only CFC concerned (55 % of total)
total
presentlyfound
with D-losseswith time
tiles
gaps
erosion thin deposits
thick deposits
TPL ~ 7 m² (of ~ 15 m² in Tore Supra)Possible total D-inventory > 10 g of the dedicated D-inventory campaign
Contribution to previous campaigns
18/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Summary
PARTICLE BALANCE & PHYSICS of RETENTION
First results : ~ 50% of wall D-inventory found in Toroidal Limiter(up to 70 % if D-losses with time taken into account)
Retention on limiter: ~ 10% in CFC, ~90 % in deposits
Constant retention rate for the whole campaign, no saturation2g/h D, i.e. 60% of injected flux
Increase of wall D-inventory ~10g (~3×1024 D)
PLASMA-WALL INTERACTION & D-INVENTORY
5h of plasma in long pulse (>1min) operationScenario modified due to increasing number of UFOs and disruptionsNo change in the main plasma parameters
Largest flakes probably the consequence of repetitive discharges(constant wetting and constant deposition at exactly the same location)
OPERATION
19/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Additional viewgraphs
20/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Previous TS results (C. Brosset et al., JNM 2005)
All deposits far from LCFS but significant plasma flux (~ to B)Deposits on TPL surface, close to LCFS but no direct plasma flux not collected
Collection after campaign with high power discharges (high temperature of deposits)
0.3g D found (2.6g estimated Wall Inventory)
Extrapolated to present Wall Inventory (10g) 1.2g
21/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Attempt for global C-balance (from J.Hogan et al., IAEA 2006)
750m
D-load exp. 2002-2007
230g 2200g
Gross erosion (scaling law)
Net redeposition : cleaning of whole vacuum chamber ~800g deposits scrapped from PFCs
Net erosion ~ net redeposition(neglects erosion due to glows)
D-load exp. 2002-2007
100g 1000g
Net erosion
agrees with erosion from confocal scopy ~1000g eroded from TPL surface
Only ~55-65% of local C-redeposition
UFO ~0.2mg C (3mm×3mm×3m)500 UFOs during D-loading experiment ~0.12g C (5×10-4 of gross erosion)
22/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Extrapolation fuel retention to ITER
From D-loading experiment:5h of plasmas 10g of increase of wall D-inventory 4g D found in TPL
1.3g in erosion zones 2.7g in deposits
TPL = main source of C other PFCs likely deposited areas 8.7g in deposits
Extrapolation to ITER speculative becauseNot the same geometryNot the same edge parametersNot the same surface temperatures…
With respect to flux on PFCs (2 orders of magnitude)150g/h 700g T after ~40 nominal discharges (400s)
In erosion zones, with respect to integrated flux (2 orders of magnitude) : 20g/hwith respect to loaded surface (~1order of magnitude) : 2g/h
In deposited zones, with respect to net erosion (Redep = 0.55 in TS; 46g/h eroded C) (Redep = 0.99 in ITER; 27g/h): 1.5g/h(22-4)g/h 700g T after ~300-1600 nominal discharges (400s)
23/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Particle recovery after disruptions
Recovery after disruption : up to 5 1022 D
• Large scatter at given Ip : machine history dependent ?composition of gas ?
• Threshold in Ip :
• Ip < 0.8 MA : ~ after shot recovery• Ip > 0.8 MA : increase with Ip dissipated energy high enough for significant outgassing
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
Qinj-Qexh
24/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
6 anodes toroidally distributed Itot=6A applied potential : ~600 V
Tokamak walls = cathode
Station de gaz
6 gas injection points toroidally distributed
Pumping speed 2200 l.s-1
Gas injection and glow electrodes system
6 anodes toroidally distributed Itot=6A applied potential : ~600 V
Tokamak walls = cathode
Station de gaz
6 gas injection points toroidally distributed
Pumping speed 2200 l.s-1
Gas injection and glow electrodes system
0
50
100
150
200
4:48 7:12 9:36 12:00 14:24 16:48 19:12
Temp (°C)
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
Pressure (Pa)
D2 GDC He GDC He:15%B2D6 He:15%13CH4
SequenceD2-GDC : remove oxyde p=0,35 Pa duration : 180 min.
He-GDC : desorb implanted D2
p=0,4 Pa duration : 30 min.
Carbonisation : 15 bar.l 13CH4 p=0,45 Pa duration : 210 min. He:20%13CH4 80 monolayers a-13C:H
Boronisation : 7,5 bar.l B2D6
p=0,45 Pa duration : 100 min. He:15% B2D6 80 monolayers a-B:D
[D. Douai]
CONDITIONNING INITIAL SURFACE IDENTIFICATION
25/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
<ne> = 1.5×1019m-3
Ip = 0.6 MA
PLH = 1.8 MW max
Prad = 0.7 MW
<ne> = 1.5×1019m-3
Ip = 0.6 MA
PLH ~ 2 MW
Prad = 0.7 MW
2nd scenario1st scenario
125 s 85 s
Plasma scenarios
Magnetic field = 3.8 T
26/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
MARFE causes PLH switched off by security
PLH switced off if radiation increases above fixed limitLine of sight of the security system located in midplane
With increasing impurity content, MARFEs are triggered by smaller perturbations
27/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Time schedule of the radiative instability
DPrad
C IV
MARFE
Flakeejection
Hot spot outgassing (impurity) MARFE & flake ejection Prad increases swith-off PLH by security density limit
28/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Deposit pattern evolves during experiment
Deposits are thermally poorly attached to CFCIncrease of deposit thickness seen as increase of surface temperature
Movie of the TTPL during the 1st phase of the experiment
Thick deposits : private flux regions on TPLNo plasma , but radiation + CX atoms
Competition growth / erosionDeposit pattern characteristic to each scenario
29/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Plasma-wall interaction & Carbon erosion
CII 515nm
CII emission on net erosion zones + gaps
CD on net erosion zones + leading edge
CD 431nm
Carbon erosion estimated in both erosion and deposition regionsTotal erosion from CII/D ratio: Ytot ~1%
Chemical erosion from CD/D ratio:low S/N, data consistent with Ychem1%
Gross erosion estimated from Ytot + BBQ simulations (J.Hogan et al., IAEA 2006)
For the whole campaign ~ 230 g
30/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Constant plasma edge parameters
[J. Lasalle, L. Manenc]
Temperature :3.97 3.975 3.98 3.985 3.99 3.995
x 104
0
5
10
15
20
25
30
shot
Te [e
V]
r - rLCFS
~ 2 cm
r - rLCFS
~ 7 cm
[M. Kocan, J. Gunn, J.-Y. Pascal]
Edge density and temperature :
0
20
40
60
80
100
tem
pe
ratu
re [
eV
]
Ti
Te
T
i,e
0.06m
= Ti / T
e 3.5
0.02 0.04 0.06 0.08 0.1 0
0 0.02 0.04 0.06 0.08 0.1 0.1210
17
1018
distance from the LCFS [m]
De
nsi
ty [
m-3]
ne(T
i = 3.5T
e)
ne(T
i = T
e)
n
e
0.07m
n
e
0.04m
31/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Constant plasma core parameters
[J. Lasalle, L. Manenc]
Temperature :
Density : feed-back controlled <ne> = 1.5×1019 m-3
No uncontrolled increase during the whole campaign No significant change in the profile
[C. Gil, R. Sabot]
Scenario 1# 39777# 39930
Scenario 2# 39990# 40030
32/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Moderate increase of impurity content
Constant core and edge plasma parameters ne(0)~2.7×1019m-3 ; Te(0)~3.5keV ; ne(a)~2×1018m-3 ; Te(a)~25eV
Moderate increase of impurity content
33/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
Toroidal gaps
Poloidal gaps Top (plasma)
Bottom (copper)
Sample analysis
Toroidal gaps
Poloidal gaps
34/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
depth (m)
[D]/[
C]
Poloidal gaps, erosion zone
Répartition du D dans les parties latérales toroïdales des tuiles en zone d'érosion.
0
5000
10000
15000
20000
25000
1 2 3 4 5 6 7
Profondeur en mm du plasma au Cu
No
mb
re d
e D
en
1E
15
D/c
m²
F1T3Q4L1
F4T2Q4L1
F26T9Q4L1
F26T11Q4L1
F27T8Q4L1
Top (plasma) Bottom (copper)
35/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
depth (m)
[D]/[
C]
Poloidal gaps, thin deposits
Dépôts fins Gap
0
50
100
150
200
250
300
350
400
450
500
1 2 3 4 5 6 7
F17T7Q4L1
F27T20Q4L1
Top (plasma) Bottom (copper)
36/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
depth (m)
[D]/[
C]
Poloidal gaps, thick deposits
Répartition GAP dépôts épais
0
5000
10000
15000
20000
25000
1 2 3 4 5 6 7
profondeur en mm
no
mb
re d
e D
en
1E
15D
/cm
²
F4T9Q4L1
F26T3Q4L1
F27T4Q4L1
Top (plasma) Bottom (copper)
37/18
TORE SUPRA
AssociationEuratom-Cea
B. Pégourié – SEWG “Gaz Balance & Fuel Retention” - JET – July 22-23, 2008
PA
RT
ICL
E B
AL
AN
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- R
ET
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TIO
NErosion zones : Mechanism for D-retention
Erosion zone : D-content ~100× that expected from implantation
5 µm
100 µm
Porosity probably involved in retention process
Filling up of pores by hydrocarbonsOn a layer of 15m thickness(average depth of D in erosion zone)
2g of D for the Limiter
(compared with 1.3g already found)
CFC = porous material ~20% of voids