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1TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA D program: Specific experiments before dismantling Purpose:

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Presentation on theme: "1TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA D program: Specific experiments before dismantling Purpose:"— Presentation transcript:

1 1TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA D program: Specific experiments before dismantling Purpose: find/or not significant D amount in the CFC explain the lacking D in TS particle balance Can we close the particle balance as it is ? or Do we need specific experiments ?

2 2TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA 1-discharge particle balance These conditions: retained flux : D/s Flux Gas puff Paroi Pompes LPT+tore Plasma Post-discharge outgassing

3 3TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA 1-day particle balance 7 x 200 s ~ 1400 s of plasma 2.5x10 23 D 15 x 20 s ~ 300 s of plasma Short pulses: particle balance closed with He glows Long pulses: significant contribution to wall inventory 6h of He glows : 1.5-2x10 22 D recovered 2.5x10 22 D

4 4TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA global particle balance WI = period (Q inj –Q exh )- period Q glow - period Q disrpt - …) No reliable estimation of the wall inventory probably > D atoms Q inj – Q exh ~ /s for long discharges (LD) < /s for short discharges (SD) Q glow for a night of glows Q disrpt ~ per disruption End of 2004 : s of plasma, of which LD WI ~ ??? D atoms (Tsitrone, IAEA2004) Now : 2 years, i.e. > s of plasma later SD ???

5 5TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA C-layers in the close SOL: [D]/[C] ~ 1-10 % C-layers in the far SOL: [D]/[C] ~ % surface/thickness of carbon layers difficult to assess strong assumption on the D concentration profile complete collection of carbon layers not unrealistic Deposited C-layers found in different places (Brosset, PSI2006) TPL (upper surface / back of the tiles) neutralisers outboard movable limiter LH launcher Poloidal inner bumpers Water-cooled copper tube of protection against ripple electrons Importance of co-deposition Post-mortem analyses: inventory D Present day wall inventory: > 8 x D > 7 x D still missing

6 6TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA Why a dedicated experiment ? Good indication that deep diffusion plays a role D-implantation in CFC does not saturate (J. Roth) [D]/[C] ~ % up to 10 m in AUG tiles in Tore Supra PFCs : ~ C atoms [D]/[C] ~ 0.01 % in the whole PFCs [D]/[C] ~ 1 % 1 mm in the loaded zones of TPL to account for present WI But: no accurate value for present wall inventory Impossible to close reliably the particle balance possibly dominated by LD performed 4 years ago Low [D]/[C] if diluted in large volume Necessity of dedicated experiment to charge the TPL in D in a controlled way and with accurate particle balance

7 7TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA What do we need ? Requirement: WI >> estimated present WI 8x10 23 D For good accuracy : WI ~ 4x10 24 D (~ 5 x WI) Retained flux ~ 2x10 20 /s -> 2x10 4 of LD (equivalent to a year of operation) …rough estimate… 160 LD of 2 min ~ 11 days of operation (15 LD/day) Routine LD scenario: nl ~ 2x10 19 m -2 I p = 0.6 MA P LH ~ 2.5 MW

8 8TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA Why a better accuracy ? WI = period (Q inj –Q exh ) No He-glows and (hopefully) no disruptions Characterization of the plasma outflux out and recycling: Langmuir probes H, CII, (CD ?) Time-dependence of Q inj, Q exh, retention, deposits… (constant or changing with time / discharge n° ?) Incident flux distribution onto the TPL …size of the reservoir if saturation observed …dependence of retention with fluence ??? (difficult because limited range of out in loaded regions and presence of deposits in shadowed regions) Extrapolated [D]/[C] to the TPL ~ period (Q inj –Q exh )

9 9TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA Main arguments Particle balance during 1 discharge or 1 day is accurate but we cannot estimate reliably the wall inventory over long periods (i.e. the total wall inventory). Significant improvement obtained by charging the wall in a controlled manner, up to values > the estimated total wall inventory. This can be done in about two weeks of long-discharge operation (well developed scenario). Extrapolation of D content of analysed tiles can be quantitatively compared to measured integrated retention.

10 10TPL Dismantling Project Review 08/12/06 Bernard Pégourié TORE SUPRA Association EURATOM-CEA Injection of C 13 H 4 as a tracer Injection C 13 H 4 Line impurities: bumpers, outer wall, TPL Only long distance C-transport How much C 13 H 4 to be measured ? Only TPL: No toroidal distribution C(loaded) C(shadowded) TPL + tiles (bumpers, LPA): Poloidal & toroidal distributions More interesting but… How many tiles available ??? More analysis, activation ??? … if possible, needs a more detailed evaluation


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