R. Neu: SEWG meeting, July 7-8, The EU Plasma Wall Interaction Task Force : Work Programme 2010(-2011) R. Neu (Deputy TF leader, IPP Garching) E. Tsitrone (TF leader, CEA Cadarache) With contributions from : S. Brezinsek (FZJ), P. Coad (UKAEA), C. Grisolia (CEA), T. Loarer (CEA), K. Krieger (IPP), M. Lehnen (FZJ), G. Maddaluno (ENEA), V. Philipps (FZJ), J. Roth (IPP), M. Rubel (VR) EFDA contact: R. Zagorski (EFDA CSU Garching)

R. Neu: SEWG meeting, July 7-8, Outline 1) Introduction: the PWI TF and the ITER context 3) Summary 2) Work programme : major milestones

R. Neu: SEWG meeting, July 7-8, Introduction : the EU PWI TF and ITER context

R. Neu: SEWG meeting, July 7-8, ITER high priority research needs : strongly PWI related [D. Campbell, ITPA CC meeting June 2008] 1. Disruption/ Runaway Mitigation 2. ELM Control/ Mitigation 3. Plasma Facing Materials Physics basis for ITER reference scenarios with W/ Be PFCs ; C removal 4. Scenario Development 5. Diagnostics Dust / Hot dust ; divertor erosion ; mirrors ; H/D/T inventory Beryllium Tungsten Carbon Heat loads, runaway electrons: reduction > 1 order of magnitude Radiation cooling, supression of accumulation

R. Neu: SEWG meeting, July 7-8, Disruption/ Runaway Mitigation 2. ELM Control/ Mitigation 3. Plasma Facing Materials Physics basis for ITER reference scenarios with W/ Be PFCs ; C removal 5. Diagnostics Dust / Hot dust ; divertor erosion ; mirrors ; H/D/T inventory Heat loads, runaway electrons: reduction > 1 order of magnitude Fuel retention Fuel Removal Transient heat loads ELMs and disruptions Material erosion and transport in tokamaks Materials Material migration High-Z Materials ITER-like Material Mix Dust in fusion devices Dust EU-PWI TF : targeted at ITER through 7 SEWGs Material ErosionW R&D Fuel retention Dust Heat loads ITPA Div SOL : 5 topics 4. Scenario Development Rad. cool., accumulation supr.

R. Neu: SEWG meeting, July 7-8, Task Force Plasma-Wall Interaction Main orientations at Annual General Meeting Contact Persons from 23 associations + JET TF E and FT, EFDA, F4E, ITER IO ITPA divertor and SOL (co-chair) Special Expert Working Groups Annual specialised meeting of SEWG members Joint meetings (Material Mixing & Migration for 2009) EU PWI TF: mature organisation Associations Baseline work programme : 20 % (?) Priority support : up to 40 % EFDA ITM-TF TG MHD TG H&CD (ICWC) TG diags (LIBS) TG Mat (W alloys) TG Transp Emerging techno (Dust & T) (Disrup.)

R. Neu: SEWG meeting, July 7-8, Highlights of 2008 Strong participation in PSI and IAEA 2008 > 20 oral papers (2 PSI review), > 100 publications ITER fuel retention ITPA DivSOL MIT meeting + IAEA + final report Joint meeting (ITM / MHD / PWI) on disruptions Preparation of WP2009 in new EFDA frame Call for interest launched in Summer 08 Task agreements finalised early 09 Annual meeting Frascati Oct reporting : WP % executed (5% delayed)

R. Neu: SEWG meeting, July 7-8, Definition of the Work Program for the next year(s) Presentation of the n+1 annual WP to EFDA SC (main lines – ceiling) (Feb-March) Call for Participation for n+1 WP (summer) Answer to call (early Sept) Call assessment by PWI TF (end Sept) Presentation to EFDA SC for approval (Oct) Task agreements drafted for n+1 WP (Nov) Implemented by end of the year SEWGs meetings Annual PWI TF meeting, reporting on current WP Timeline for the PWI TF Next call : July 2009 for 2010

R. Neu: SEWG meeting, July 7-8, Work programme : major milestones

R. Neu: SEWG meeting, July 7-8, Main orientations for Strengthening of modelling for extrapolation to ITER and DEMO – Interpretative modelling for benchmarking tools used for ITER simulations (SOLPS, ERO, DIVIMP …) – in close connection with ITM-TF (code development) 2 years WP : TA2010 and TA2011 will be very similar Integrated plasma operation : impact of impurity seeding – erosion, mixed material, fuel retention … Including recent ITER requests – disruptions/runaways – W R&D – divertor re-attachment heat loads – IC wall conditioning Bilateral collaborations : – mixed materials : PISCES (US) EFDA PWI TF (EFDA call for long term visiting scientist, deadline August 15!) – material damage : plasma guns (RF) F4E, but modelling + dust = PWI TF

R. Neu: SEWG meeting, July 7-8, Materials SEWG Material migration Main wall erosion / redeposition Impact of impurity seeding on erosion Benchmark/development (gaps …) of local erosion/redep codes (ERO, …) SEWG High Z Impact of impurity seeding on W erosion Control of W contamination : erosion (ELMs, ICRH) core W + interpretative modelling of W erosion and transport Operation on damaged W PFCs + modelling of W damage & melt layer motion Liquid metals SEWG Material mixing Binary systems : comparison lab vs tokamak mixed deposits Impact of impurity seeding + thermal excursions (ELMs) on mixed material formation Extension of transport codes to simulate material mixing at the walls MD modelling of mixed material formation

R. Neu: SEWG meeting, July 7-8, Fuel retention / removal / dust SEWG Fuel retention Multi machine scaling of fuel retention benchmark for ITER prediction methodology Post mortem : fuel location (gaps, bulk …) fuel removal SEWG Fuel removal Impact on dust production IC wall conditionning Removal in gaps SEWG Dust Dust conversion factor (gross erosion dust) Metallic dust Dust from maintenance, cleaning Dust from transients (Bilateral collaboration with RF on plasma guns F4E) Modelling of dust creation and transport Coordination TG Diag / EFDA Emerging techno needed : indication of (+ F4E / ITER IO) other calls!

R. Neu: SEWG meeting, July 7-8, Transient heat loads Disruptions Particle and heat fluxes during disruptions (fast diags needed) –Asymmetries (convective + radiative fluxes) –Runaways : modelling needed –Heat loads in mitigated disruptions (MGI) Optimisation of disruption mitigation (MGI), including runaways suppression –Modelling needed for MGI impact (penetration, radiation …) Coordination MHD TG / ITM TF / F4E / ITER IO : joint meeting Feb 09 ELMs and inter ELMs heat loads Heat fluxes for unmitigated vs mitigated ELMs Main chamber : far SOL transport and fast particles Heat loads during loss of detachment events Material damage (Bilateral collaboration with RF on plasma guns F4E) Modelling of material damage & melt layer motion benchmark vs plasma guns + tokamaks SEWG Transients

R. Neu: SEWG meeting, July 7-8, Total TA2009 : 22.6 ppy (+ 4 ppy for new associations) Total WP2010 : ppy EFDA emerging techno + F4E High Z Disruptions Resources for 2010 : priority support

R. Neu: SEWG meeting, July 7-8, ITER : several top priority issues are PWI related (disruptions, ELMs, W R&D, diags for dust and T) EU PWI TF : reactive to ITER requests (ICWC, divertor reattachment) Summary Coordination : European (other EFDA TF/TGs, F4E) and international (bilateral collaboration with US, ITPA) work programme established : Disruptions and high Z materials Modelling for extrapolation to ITER and DEMO Next call : July 2009 (new tool: ECOM, deadline September 5) SEWG meetings : fuel retention/removal/dust : June15-17, Cadarache material migration / mixed materials : July 8-7, JET transient heat loads / High Z : October 1-2, Ljubljana PWI TF meeting : November 4-7, Warsaw PSI conference : abstracts due November 15 Position for (young) scientist at PISCES under EFDA mobility !!! (deadline August 15)

R. Neu: SEWG meeting, July 7-8, Annex

R. Neu: SEWG meeting, July 7-8, ITPA : new organisation ITPA (International Tokamak Physics Activity) has changed Summer 2008 : IEA (International Energy Association) legal framework of ITER Central coordinating committee : 3 representatives from each ITER partner Chair : R. Stambaugh (US), EU : J. Paméla, F. Romanelli, H. Zohm 7 ITPAs : Transport and confinement (S. Kaye, US) Energetic particles (S. Guenter, EU) Integrated operation scenario (S. Ide, JA) MHD stability (A. Sen, IN) Pedestal (H. Wilson, EU) Diagnostics (R. Boivin, US) Divertor and SOL (B. Lipschultz, US) New leadership for each group B. Lipschultz (chair), E. Tsitrone (co chair), R. Pitts (ITER co chair) selected Stronger connection to ITER organization : info + concerns both ways Coordinated experiments : DSOL (IEA on large tokamaks), international database

R. Neu: SEWG meeting, July 7-8, Disruption/ Runaway Mitigation 2. ELM Control/ Mitigation 3. Plasma Facing Materials Physics basis for ITER reference scenarios with W/ Be PFCs ; C removal 5. Diagnostics Dust / Hot dust ; divertor erosion ; mirrors ; H/D/T inventory Heat loads, runaway electrons: reduction > 1 order of magnitude Fuel retention Fuel Removal Transient heat loads ELMs and disruptions Material erosion and transport in tokamaks Material migration High-Z Materials ITER-like Material Mix Dust in fusion devices Dust Towards increased coordination … F4E EFDA Emerging Techno Diag TG MHD TG, ITM TF H & CD TG US : PISCES RF : plasma guns

R. Neu: SEWG meeting, July 7-8, SEWG Proposed Task Agreements for SEWG Fuel retentionTA-1: Fuel retention analysis as a function of wall materials foreseen for ITER SEWG Fuel removalTA-2 : Exploration of fuel removal methods compatible with retention in mixed materials and metals (Be) SEWG Dust in Fusion Devices TA-3: Dust generation and characterization in different devices SEWG Material MigrationTA-4: Erosion, transport and deposition of low-Z wall materials SEWG High-Z Materials and Liquid metals TA-5: Development of the PWI basis in support of integrated high-Z scenarios for ITER and Demonstration of liquid PFCs SEWG ITER Material MixTA-6: Determination of expected alloys and compounds and their influence on PWI processes SEWG Transient Heat Loads TA-7: Mitigation of disruptions and ELM and inter-ELM heat loads WP2010: 7 Task Agreements proposed

R. Neu: SEWG meeting, July 7-8, Manpower BS (ppy) Manpower PS (ppy) Hardware PS (k) Mobility (k) TF Coordination SEWG Coordination TA-1: Fuel retention as a function of wall materials foreseen for ITER 7350 TA-2: Fuel removal compatible with retention in different and mixed first wall materials TA-3: Dust generation and characterization in different devices TA-4: Erosion, transport and deposition of first wall impurities TA-5: Development of the PWI basis in support of integrated high-Z scenarios for ITER, Liquid plasma-facing components TA-6: Expected alloys and compounds and their influence on PWI processes TA-7: Mitigation of disruption loads for ITER, ELM and inter-ELM heat loads Total91 ppy23.75 ppy400 k350 k Overview of resources requested for 2010 NB : resources requested for 2011 ~ same level

R. Neu: SEWG meeting, July 7-8, Overview of 2011 resources Manpower BS (ppy) Manpower PS (ppy) Hardware PS (k) Mobility (k) TF Coordination SEWG Coordination TA-1: Fuel retention as a function of wall materials foreseen for ITER 7350 TA-2: Fuel removal compatible with retention in different and mixed first wall materials TA-3: Dust generation and characterization in different devices TA-4: Erosion, transport and deposition of first wall impurities TA-5: Development of the PWI basis in support of integrated high-Z scenarios for ITER Liquid plasma-facing components TA-6: Expected alloys and compounds and their influence on PWI processes TA-7: Mitigation of disruption loads for ITER Heat load in ITER relevant ELM scenarios Total91 ppy24.25 ppy400 k350 k

R. Neu: SEWG meeting, July 7-8, Recent scientific achievements: Highlights of 2008

R. Neu: SEWG meeting, July 7-8, SEWG Material migration Migration pattern refined, modelling progressing Erosion data in ITER relevant conditions (high particle flux / low energy) : Pilot-PSI interpretation ongoing (geometry, surface temperature) Tracer experiments ongoing ( 13 C) : AUG, Textor, TS Tracer injection + post mortem + modelling Main chamber inner divertor ok Outer inner divertor ? N 2 injection in lab experiments (PSI-2 …) N 2 scavenger effect confirmed. Tokamak ? [PSI08] Progress with the ERO code : Gaps, effect of ELMs, higher C x D y But : sticking probability, surface roughness, redeposited layers re- erosion [FZJ]

R. Neu: SEWG meeting, July 7-8, SEWG High-Z Materials Radiation cooling with W walls, liquid limiters Progress in W diagnostics : IR, spectroscopy PWI basis for plasma operation with W walls (AUG) Successful operation w/o boronisation confirmed Boronisation radiation cooling essential reduced divertor heat loads Good performance in radiatively cooled plasmas (N 2 ) [PSI08, IAEA08] Effect of neutron irradiation : W specimen irradiated ( dpa) Transient heat loads Cracks but no melting. Microstructure ? [SCK-CEN, FZJ] Liquid limiters : Li in FTU, TJII : LLL (performance increased) Ga in ISTOK [ENEA] [PSI08]

R. Neu: SEWG meeting, July 7-8, Scaling of fuel co-deposition with Be, C and W : PISCES Multi factor : Tsurf, impact energy, arrival flux ratio revised modeling for T retention in ITER reduction (x 0.5) of predicted inventory due to temperature dependence SEWG ITER Material Mix: Ternary systems explored, scaling for fuel codep ITER Exploration of ternary systems : W-Be-C or Be-O-W Lab experiments but also tokamaks (W-C in Textor) 900 K 1120 K 1320 K He + ion fluence ~ 1–2×10 26 m -2 Detailed study of PWI with W : PISCES He & Be prevents blistering ( K) He driven growth of nanostructures ( K) suppressed with Be or C [PSI08] [PISCES]

R. Neu: SEWG meeting, July 7-8, SEWG Fuel retention: Low fuel retention in full W AUG, gas balance vs post mortem Low fuel retention in full W AUG confirmed both from post mortem and gas balance C : codep in inner divertor W : implantation in outer divertor [IPP] [PSI08] Towards a reliable fuel retention assessment : better consistency post mortem / gas balance DITS project in Tore Supra Significant contribution from gaps in erosion zone [PSI08, IAEA08] Development of the LIBS technique (FZJ, CEA) : benchmarked against post mortem on Textor tiles Inner div Outer div Remote

R. Neu: SEWG meeting, July 7-8, SEWG Fuel removal ICWC optimization, first trial on gaps Optimization of ICWC ongoing in Textor, Tore Supra, AUG Homogeneity of ICWC plasma (B field) Gas composition (He/D 2 ) [MedC] [CEA] Removal in gaps thermo-oxydation (CIEMAT), ECR or GDC (IPP, FZJ), laser (CEA), plasma torch (MedC) [PSI08, IAEA08] Dust production during cleaning processes : laser cleaning (IPPLM, VR) : dust/flake production with significant fuel content

R. Neu: SEWG meeting, July 7-8, SEWG Dust Dust measurements during plasma, first dust injection experiments Dust measurements during plasma operation : CCD (TS, AUG), fast IR (AUG), electrostatic detector (TS), Thomson scattering (FTU) Dust collection ongoing : AUG, Textor, Tore Supra, FE200 Complex structure for C dust, spherical for W (droplets from transients ?) [PSI08] [FZJ] Preliminary dust injection experiments in Textor Driving force = j x B Edge C increased, no effect in core

R. Neu: SEWG meeting, July 7-8, SEWG Transient heat loads Progress in fast diagnostics, mitigation with MGI [CRPP] Transient heat loads : progress in fast diagnostics (IR, bolometry) ELM filamentation, radiation during MGI Hardware exchange foreseen (fast IR) [PSI08, IAEA08] Material damage : collab RF plasma guns (F4E) + Judith (repetitive ELMs) [PSI08] Kinetic modelling of thermal loads in gaps : peak heat flux 2-3 x larger than tile surface (IPP.CR) Mitigation of transients : first experiments with RMPs on MAST dithering ELMs MGI (TS, AUG, TCV …) : Radiation not axisymmetric. Runaways ? Disruption avoidance with ECRH : ENEA, IPP [PSI08] [IAEA08]