The EU Plasma Wall Interaction Task Force : Recent Achievements and Midterm Plans

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The EU Plasma Wall Interaction Task Force
Recent Achievements and Midterm Plans
R. Zagórski PWI Responsible Officer EFDA CSU
Garching Special thanks to E. Tsitrone (CEA)
and R.Neu (IPP) and EU TF on PWI
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Outline
1) What is the EU PWI TF?
2) Recent achievements of the PWI TF
highlights of 2008
3) Work programme 2009-2010/11 major
milestones
4) Summary
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What is the EU PWI TF ?
The aim of the Task Force is to concentrate
European research on the most urgent problems in
the field of PWI for ITER and future devices, and
to propose scientific and technological concepts
to overcome these problems.
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ITER high priority research needs strongly PWI
related
1. Disruption/ Runaway Mitigation
Heat loads, runaway electrons reduction gt 1
order of magnitude
2. ELM Control/ Mitigation
reduction gt 1 order of magnitude
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
D. Campbell, ITPA CC meeting June 2008
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EU-PWI TF targeted at ITER through 7 SEWGs
1. Disruption/ Runaway Mitigation
Heat loads, runaway electrons reduction gt 1
order of magnitude
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
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EU PWI TF mature organisation
Task Force Plasma-Wall Interaction Main
orientations at Annual General Meeting Contact
Persons from 23 associations JET TF E and FT,
EFDA, F4E, ITER
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Timeline for the PWI TF
Presentation of the n1 annual WP to EFDA SC
(main lines ceiling) (feb-march)
SEWGs meetings
Call for Participation for n1 WP (summer)
Next call July 2009 for 2010
Answer to call (early sept) Call assessment by
PWI TF EFDA(end sept) Presentation to EFDA SC
for approval (oct)
Task agreements drafted for n1 WP
(nov) Implemented at the beginning of the year
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Priority support selection criteria 2010

• Baseline support no ceiling, proposals from
  associations ( 90 ppy)
• Priority support ceiling for ppy ( 24 ppy
  ppy) and hardware ( 400 kEuros)
• ? selection
• Rejected
• not in the scope of the PWI TF WP
• JET related work
• Reduced (? shifted to BS)
• non collaborative work (unless priority like
  T/Be related work, modelling)
• no associated effort in BS
• ceiling limit
• TF leadership (leader deputy) (0.5 ppy) EFDA
  SC on proposal by EFDA leader, 3 years term ?
  2009-2011
• SEWG leadership (0.25 ppy) EFDA on proposal
  from PWI TF leadership,
• term ? 1 year -2 years

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Recent scientific achievements highlights of
2008
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• SEWG Material migration
• Migration pattern refined, modelling progressing

• Tracer experiments ongoing (13C) AUG, Textor,
  TS
• Tracer injection post mortem modelling
• General transport Main chamber ? inner divertor
  ok
• Additional channel Outer ? inner divertor ?

• Erosion data in ITER relevant conditions (high
  particle flux / low energy)
• Pilot-PSI ? interpretation ongoing (geometry,
  surface temperature)

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SEWG High-Z Materials Radiation cooling with W
walls, liquid limiters

• PWI basis for plasma operation with W walls
  (ASDEX-U)
• Successful operation w/o boronisation confirmed
  (H?1)
• Boronisation ? radiation cooling essential ?
  reduced divertor heat loads
• Good performance in radiatively cooled plasmas
  (N2)

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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)

• Scaling of fuel co-deposition for Be, C and W
  PISCES
• Multi factor Tsurf, impact energy, arrival flux
  ratio
• ? revised predictions for the T retention in
  ITER

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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 codeposition
in inner divertor W implantation/diffusion in
outer divertor
IPP
Inner div
Outer div
Remote
C
W
Towards a reliable fuel retention assessment
better consistency post mortem / gas
balance DITS (Deuterium Inventory in Tore Supra)
project in Tore Supra Gas balance / Post mortem
2 Significant contribution from gaps in erosion
zone
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SEWG Fuel removal ICWC optimization, first trial
on gaps
Chemical Methods N2, NH3 ? ITER Optimization
of ICWC ongoing (in Textor, Tore Supra, AUG) Gas
composition (H2, D2, O2, N2, NH3 ,He )
Homogeneity of ICWC plasma (B field)
Dust production during cleaning processes
laser cleaning (IPPLM, VR) dust/flake
production with significant fuel content
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SEWG Dust Dust measurements during plasma, first
dust injection experiments
Dust collection ongoing JET, AUG, Textor, Tore
Supra, FE200 Complex structure for C dust,
spherical for W (droplets from transients ?)
? Conversion factor 5-8 in TS
Dust measurements during plasma operation CCD
(TS, AUG), fast IR (AUG), electrostatic detector
(TS), Thomson scattering (FTU)
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SEWG Transient heat loads Progress in fast
diagnostics, mitigation with MGI
Transient heat loads progress in fast
diagnostics (IR, bolometry) ? ELM filamentation,
radiation during MGI Hardware exchange foreseen
(fast IR)
CRPP
Material damage collab RF plasma guns (F4E)
Judith (repetitive ELMs) Progress in
Modelling (FZK)
Mitigation of transients pellets (AUG) RMPs
first experiments on MAST ? dithering ELMs
(JET, AUG) MGI (TS, AUG, TCV ) Runaways ?
Radiation not axisymmetric ? heat loads ?
local melting.
Kinetic modelling of thermal loads in gaps peak
heat flux 2-3 x larger than tile surface (IPP.CR)
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Work programme 2009-2010/11 major milestones
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Main orientations for 2010/11

• Bilateral collaborations
• mixed materials PISCES (US) ? EFDA PWI TF
• material damage plasma guns (RF) ? F4E, but
  modelling dust PWI TF

• Including recent ITER requests
• disruptions/runaways
• W RD
• divertor re-attachment heat loads
• IC wall conditionning

• Integrated plasma operation impact of impurity
  seeding
• erosion, mixed material, fuel retention

• 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)

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SEWG fuel retention
TA 1 Fuel retention as a function of wall
materials foreseen for ITER

• Milestones 2009
• Complete studies in C environment TEXTOR, TS,
  TCV, (JET)
• Retention in full W AUG
• Retention in Be/W/mixed materials PSI devices
• Projection of reliable estimates on tritium
  retention in ITER in a joint ITPA project

CEA, ENEA, FZJ, IPP, IST, Latvia, MedC, MHEST,
TEKES, UKAEA, VR
BS 6.5 ppy, PS 5.7 ppy, hardware 48 kEuros

• Key issues for 2010/11
• ? benchmark for ITER prediction methodology
• Multi machine scaling of fuel retention
• Post mortem fuel location (gaps, bulk ) ?
  fuel removal

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SEWG Fuel Removal
TA 2 Fuel removal compatible with retention in
different and mixed first wall
materials

• Milestones 2009
• Quantify the removal rates for mixed material
  films
• Resolve the impact of nitrogen molecules on
  cleaning processes
• Impact of repetitive oxidising plasmas (GDC/RF)
  on beryllium bulk properties.
• Effect of sample temperature for oxidative or
  advanced chemical cleaning on oxide film
  formation, and beryllium oxide removal rates
• Removal of deposited films in tile gaps and
  castellations
• Improve the efficiency of flash-lamp cleaning

CEA, CIEMAT, ENEA, FOM, FZJ, IPP, IPPLM, MedC,
MHEST, UKAEA, VR
BS 11.9 ppy, PS 1.5 ppy, hardware 30 kEuros

• Key issues for 2010/11
• Impact on dust production
• IC wall conditionning
• Removal in gaps

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SEWG Dust in Fusion Devices
TA 3 Dust generation and characterization in
different devices

• Milestones 2009
• Dust conversion factor evaluation
• TS, MAST, AUG, FTU (JET for comparison)
• Operational consequences of dust in current
  machines
• on disruptions and diagnostics
• Control of dust creation process via layer
  stabilisation
• Laboratory studies, dedicated tokamak experiments

CEA, CIEMAT, ENEA, FZJ, IPP, UKAEA, VR
BS 7.9 ppy, PS 0.9 ppy, hardware 30 kEuros

• Key issues for 2010/11
• Dust conversion factor (gross erosion ? dust)
• Metallic dust
• Dust from maintenance, cleaning
• Dust from transients (collaboration with RF on
  plasma guns ? F4E)
• Modelling of dust creation and transport

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SEWG Material Migration
TA 4 Erosion, transport and deposition of first
wall impurities

• Milestones 2009
• Global material transport investigations
  (erosion/redeposition balance)
• Tracer injection experiments (13CH4, SiH4,
  Be-evaporation, WF6) in tokamaks and associated
  plasma transport modelling
• Erosion and redeposition in gaps
• Re-erosion and in-situ layer disintegration of C
  layers on first wall materials such as W and Be

CEA, CIEMAT, DCU, Cyprus, FOM, FZJ, IPP, IPP.CR,
IST, MedC, MHEST, OAW, TEKES, UKAEA
BS 18.1 ppy, PS 3.6 ppy, hardware 13 kEuros

• Key issues for 2010/11
• Main wall erosion / redeposition
• Impact of impurity seeding on erosion
• Benchmark/development of local erosion/redep
  codes (ERO, )

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SEWG High-Z Materials
TA 5 Development of the PWI basis in support of
integrated high-Z scenarios for ITER
BS 16.4 ppy, PS 1.9 ppy, hardware 120
kEuros TA 6 Liquid plasma-facing components
BS 1.7 ppy, PS 0.9 ppy

• Milestones 2009
• PWI aspects of all-W AUG operation
• Melt layer behaviour under realistic conditions
• Interaction of plasma with metallic surfaces
• Potential of liquid metal PFCs

CEA, ENEA, FOM, FZJ, FZK, IPP, IPPLM, IST, MHEST,
OAW, SCK-CEN, TEKES, VR

• Key issues for 2010/11
• 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

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SEWG ITER Material Mix
TA 7 Expected alloys and compounds and their
influence on PWI processes

• Milestones 2009
• Compound formation in binary and ternary systems
  of Be, C, W and O
• Material intermixing and fuel retention behaviour
  under dynamic conditions
• Composition, fuel retention and chemical
  characterisation from mixed deposits in tokamaks
• Modelling of material mixing for extrapolation to
  ITER

CEA, FOM, FZJ, IPP, IPPLM, IST, MedC, TEKES, VR
BS 8.3 ppy, PS 2 ppy, hardware 10 kEuros

• Key issues for 2010/11
• 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

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SEWG Transient Heat Loads
TA 8 Mitigation of disruption loads for ITER
TA 9 Heat load in ITER relevant ELM scenarios

• Milestones 2009
• Power and particle fluxes on divertor and main
  chamber PFCs (incl. runaway fluxes) during
  disruption types expected in ITER
• AUG, TS, MAST, CV, TEXTOR, FTU, ISTTOK (JET)
• Optimisation of massive gas injection by
  coordinated experiments in conditions applicable
  to ITER
• AUG, TS, MAST,TCV, TEXTOR (JET)
• Power and particle fluxes during ELM mitigation
  by pellet injection and external pertubation
  fields in conditions applicable to ITER
• AUG, MAST (JET)
• Power and particle fluxes during type-I and
  type-III ELMs
• AUG, MAST, TCV (JET)

CEA, CRPP, ENEA, FOM, FZJ, FZK, HAS, IPP, IST,
ÖAW, SCK-CEN, UKAEA
BS 6.5 ppy, PS 1.8 ppy, hardware 26 kEuros
(TA 8)
6.6 ppy, PS 1.6 ppy, hardware 55 kEuros
(TA 9)
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SEWG Transient Heat Loads

• Key issues for 2010/11
• Material damage
• (Bilateral collaboration with RF on plasma guns ?
  F4E)
• Modelling of material damage melt layer motion
  
• benchmark vs plasma guns tokamaks
• 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 )
• 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

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Summary
EU PWI TF well targeted and reactive to ITER
requests (ICWC, divertor reattachment)
2008 Enhanced collaboration between associations,
mainly through SEWGs. Positive answer of 23
associations to the call for interest 2009 Full
integration of new associations in 2009
WP 2009 Workprogramme 2009 reflects adaptation
to the new EFDA frame Increasing collaboration
with new TGs and TFs, ITER, F4E PS for Joint
Experiments, work on T, Be, activated
materials 2010/11 Workprogramme established
(Call in preparation July 2009) Effort to
strengthen modelling for extrapolation to
ITER Emphasis on issues raised by ITER and
formulated within ITPA
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Thank you for your attention
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Tritium retention in ITER Recent EU evaluation
Roth, PPCF 2008