1. 1/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 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, a A. Escarguel, E. Gauthier, J. P. Gunn, P. Hertout, S.-H. Hong, F. Kazarian, M. Kocan, F. Linez, a Y. Marandet, A. Martinez, b M. Mayer, O. Meyer, P. Monier-Garbet, P. Moreau, P. Oddon, J.-Y. Pascal, F. Rimini, b J. Roth, F. Saint-Laurent, F. Samaille, S. Vartanian, a C. Arnas, E. Aréou, C. Gil, J. Lasalle, L. Manenc, a C. Martin, a M. Richou, a P. Roubin, R. Sabot Association Euratom-CEA, CEA/DSM/DRFC, CEA Cadarache, F-13108 Saint-Paul-lès-Durance a PIIM, CNRS/Université de Provence, F-13397 Marseille b MPI 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. 2/18 TORE SUPRA Association Euratom-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 inventory goal: 12g of D, i.e. 5 × pre-campaign estimation May 23 th - June 7 th, 2007 Dismantle one sector (20°) of the Toroidal Pumped Limiter Extract 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 OPERATION INCREASE of IN-VESSEL D-INVENTORY INTEGRATED PARTICLE BALANCE PHYSICS of RETENTION Detailed results on sample analysis (E. Tsitrone) Diagnostic of plasma-surface interaction (E. Delchambre)

3. 3/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 OPERATION

4. 4/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 OPERATION 10 0 10 -1 10 -2 10 -3 10 -4 10 -5 Pressure in the torus (Pa) 0 50 100 150 200 250 300 350 400 Time (h) since the beginning of the campaign 10 days of operation in 3 weeks 160 « identical » long discharges (between 1 and 2 minutes) 5h of plasma (about a normal year of operation) Carbonization 13 C + boronization Time schedule of the campaign nl ~ 2.5x10 19 m -2 P LH ~ ramp up 1.3 1.8 MW Plasma duration 80 s nl ~ 2.5x10 19 m -2 P LH ~ 2 MW Plasma duration 120 s Plasma scenario: retention >> post-discharge recovery

5. 5/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Disruptions due to UFOs limit plasma duration OPERATION UFO : Increase in Prad > 20% Scenario 1 Scenario 2 39750 Discharge number 40060

6. 6/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 OPERATION ~85% of disruptions associated to flake ejection from the limiter surface from the LH-launchers Hot spot outgassing (impurity) MARFE & flake ejection P rad increases swith-off P LH by security disruption No change in core & edge parameters (moderate increase in impurity content)

7. 7/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 OPERATION Deposit pattern evolves during experiment BeginningEnd of 1st phase Deposits are thermally poorly attached to CFC Increase of deposit thickness seen as increase of surface temperature T-T ref Thick deposits : private flux regions No plasma, but radiation + CX atoms Competition growth / erosion Pattern characteristic to each scenario

8. 8/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 BUILDING D-INVENTORY

9. 9/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 D-INVENTORY WI = Inj.Gas – Exh.Gas – Post.Rec Constant D-retention rate during campaign Exh Normal discharge Disruption Retention rate ~ 2 g/h Total increase of in-vessel inventory ~ 11 g deuterium

10. 10/18 TORE SUPRA Association Euratom-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-INVENTORY Global wall inventory (1) Total correction ~ 0.4g D

11. 11/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Background chamber pressure 6×10 -5 Pa ( 50% D 2 ) Total exhausted ~ 0.6g D Global WI ~ 10g D (3.0×10 24 atoms) Global wall inventory (2) Global WI = WI during plasmas – exhaust during nights & week-ends D-INVENTORY

12. 12/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 PARTICLE BALANCE - RETENTION

13. 13/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Tile selection for analysis PARTICLE BALANCE - RETENTION 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. 14/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 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] profiles PARTICLE BALANCE - RETENTION Gaps < 400°C

15. 15/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 PARTICLE BALANCE - RETENTION Tile analysis : Thermodesorption Integrated over Toroidal Limiter surface Total 4g Deuterium : 40% of D-loaded Erosion zone Thin deposits Thick deposits D atoms desorbed / sample 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/m 2 0.4g/m 2

16. 16/18 TORE SUPRA Association Euratom-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) PARTICLE BALANCE - RETENTION

17. 17/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 6 months ~ 65 % PARTICLE BALANCE - RETENTION D-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 presently found with D-losses with 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. 18/18 TORE SUPRA Association Euratom-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 saturation 2g/h D, i.e. 60% of injected flux Increase of wall D-inventory ~10g (~3×10 24 D) PLASMA-WALL INTERACTION & D-INVENTORY 5h of plasma in long pulse (>1min) operation Scenario modified due to increasing number of UFOs and disruptions No 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. 19/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Additional viewgraphs

20. 20/18 TORE SUPRA Association Euratom-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. 21/18 TORE SUPRA Association Euratom-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) 750 m 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 × 3 m) 500 UFOs during D-loading experiment ~0.12g C (5×10 -4 of gross erosion)

22. 22/18 TORE SUPRA Association Euratom-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 because Not the same geometry Not the same edge parameters Not 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/h with 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. 23/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Particle recovery after disruptions Recovery after disruption : up to 5 10 22 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 Q inj -Q exh

24. 24/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 6 anodes toroidally distributed I tot =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 I tot =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 Sequence D2-GDC : remove oxyde p=0,35 Pa duration : 180 min. He-GDC : desorb implanted D 2 p=0,4 Pa duration : 30 min. Carbonisation : 15 bar.l 13 CH4 p=0,45 Pa duration : 210 min. He:20% 13 CH4 80 monolayers a- 13 C:H Boronisation : 7,5 bar.l B 2 D 6 p=0,45 Pa duration : 100 min. He:15% B 2 D 6 80 monolayers a-B:D [D. Douai] CONDITIONNING INITIAL SURFACE IDENTIFICATION

25. 25/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 = 1.5×10 19 m -3 I p = 0.6 MA P LH = 1.8 MW max P rad = 0.7 MW = 1.5×10 19 m -3 I p = 0.6 MA P LH ~ 2 MW P rad = 0.7 MW 2 nd scenario 1 st scenario 125 s 85 s Plasma scenarios Magnetic field = 3.8 T

26. 26/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 MARFE causes P LH switched off by security P LH switced off if radiation increases above fixed limit Line of sight of the security system located in midplane With increasing impurity content, MARFEs are triggered by smaller perturbations

27. 27/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Time schedule of the radiative instability D P rad C IV MARFE Flake ejection Hot spot outgassing (impurity) MARFE & flake ejection Prad increases swith-off PLH by security density limit

28. 28/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Deposit pattern evolves during experiment Deposits are thermally poorly attached to CFC Increase of deposit thickness seen as increase of surface temperature Movie of the T TPL during the 1st phase of the experiment Thick deposits : private flux regions on TPL No plasma, but radiation + CX atoms Competition growth / erosion Deposit pattern characteristic to each scenario

29. 29/18 TORE SUPRA Association Euratom-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 regions Total erosion from CII/D ratio: Y tot ~1% Chemical erosion from CD/D ratio: low S/N, data consistent with Y chem 1% Gross erosion estimated from Y tot + BBQ simulations (J.Hogan et al., IAEA 2006) For the whole campaign ~ 230 g

30. 30/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Constant plasma edge parameters [J. Lasalle, L. Manenc] Temperature : [M. Kocan, J. Gunn, J.-Y. Pascal] Edge density and temperature : 0 20 40 60 80 100 temperature [eV] T i T e T i,e 0.06m = T i / T e 3.5 0.020.040.060.080.1 0 00.020.040.060.080.10.12 10 17 10 18 distance from the LCFS [m] Density [m -3 ] n e (T i = 3.5T e ) n e (T i = T e ) n e 0.07m n e 0.04m

31. 31/18 TORE SUPRA Association Euratom-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 = 1.5×10 19 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. 32/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 Moderate increase of impurity content Constant core and edge plasma parameters n e (0)~2.7×10 19 m -3 ; T e (0)~3.5keV ; n e (a)~2×10 18 m -3 ; T e (a)~25eV Moderate increase of impurity content

33. 33/18 TORE SUPRA Association Euratom-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. 34/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 depth ( m) [D]/[C] Poloidal gaps, erosion zone Top (plasma) Bottom (copper)

35. 35/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 depth ( m) [D]/[C] Poloidal gaps, thin deposits Top (plasma) Bottom (copper)

36. 36/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 depth ( m) [D]/[C] Poloidal gaps, thick deposits Top (plasma) Bottom (copper)

37. 37/18 TORE SUPRA Association Euratom-Cea B. Pégourié – SEWG Gaz Balance & Fuel Retention - JET – July 22-23, 2008 PARTICLE BALANCE - RETENTION Erosion 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 hydrocarbons On a layer of 15 m 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