Prsentation PowerPoint

1
Transport (theory), accumulation area
Creation
WP ITER
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
2
Transport (theory), accumulation area
Creation
WP ITER
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
3
Transport (theory), Accumulation area
Area which progressed
EU task activity
Creation
Safety limit assessment
WP ITER
ITER prediction
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
Maintenance
EU UKEA (Patel)
Chemical reaction with gases
EU J. Winter
BE Benchmark Experiment
From layer to dust
Structural stresses relaxation
Low energy Plasma
High energy plasma
Nucleation model
Laser/matter interaction
Fractal code
Codes
Codes
EU X. Bonnin
EU T. Itina
BE
BE
Casimir
Laser ablation
EU DPC
Dusty plasma laboratory
Experiments
Plasma gun
Experiments
EU Pestchanyi
Glow conditioning
Arc (glow)
Tokamak
Grid,
Tokamak
Grid, .
4
Transport (theory), Accumulation area
Creation
WP ITER
EU SH Hong (JET, Tore Supra, AUG)
Dust and Tokamak operation
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
BE
Dust Injection
BE
EU S. Rosanvallon (Tore Supra/PPPL) G.
Maddaluno (FTU)
Transport Codes
Diag Plasma
US DIIID
EU Imperial College/Mast
Diff Rayleigh
Calibration for diag in between plasma (quantity)
EU G. Maddaluno (FTU)
US Oak Ridge
US PPPL
Electrostatic
EU V. Rohde (AUG) S. Rosanvallon (Tore Supra)
US DIIID, Alcator
Fast CCD, IR
EU SH Hong (JET, Tore Supra, AUG), V. Rohde (AUG)
Other techniques (dusty plasma)
EU B. Annaratone
Homogeneity of measurements!!!!
5
Transport (theory), Accumulation area
Creation
WP ITER
Calibration from dust injection (transport
studies)
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
Diag in between plasma
EU J. Wolowski, S. Rosanvallon
Review
Microbalance (part of TQ)
EU G. Maddaluno
Laboratory experiments
Suspension codes
Diff Rayleigh
US INEEL
US INEEL
US INEEL
Suspension
Impacteur (DS/TQ)
EU CEA
EU ENEA FZK, CEA/CNRS
EU CEA, FZK
Gas injection
BE
Laser extinction Spectrometry (DS)
EU F. Onofri
Laser interaction
EU P. Delaporte
Erosion (TQ)
EU CEA
Deposition (DHS)
EU CEA
6
Transport (theory), Accumulation area
Creation
WP ITER
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal

• Dust diagnostics (WP 2008-.)
• Operational consequences of dust during plasma
  operation
• use of fast CCD cameras and movies automatic
  analysis.
• Correlation between CCD dust signals, edge
  spectroscopic measurements and disruption.
• Optical measurements of dust in suspension.
• Assessment of the relation between dust in
  suspension measurements
• and the total quantity recollected
• Thomson scattering system used during plasma
  operation
• Electrostatic grids (AUG TS)
• Calibrated dust injection (FTU TS)

7
Transport (théorie), accumulation area
Creation
WP ITER
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
Lab. Studies on plane surfaces and in
gaps/castellations
Review
EU S. Rosanvallon, J. Wolowski
Electrostatic extractor
Laser ( plasma) (PhD)
EU Delaporte, Winter
Suspension
Laser Ablation (synergy)
Gas injection
Suction
EU UKAEA/JET
Suspension (total quantity)
Dust conveyor
EU UKAEA/University
Use of fluids
Dust removal Efficient removal system to be
tested in mock up
8
Transport (theory), accumulation area
Creation
WP ITER
Total quantity (TQ) Dust suspension (DS) Dust on
hot surfaces (DHS)
Dust characterisation
Dust removal
Others
Structure of Tokamak dusts
SSA reactivity (common procedures)
Chemical composition
US INEEL
US INEEL
EU S. Rosanvallon (TS), V. Rohde (AUG), C.
Arnas (MAST)
EU P. Roubin (TS)
EU CEA, CNRS, FZK
Dust collection characterisation Dust
characterisation (MEB analysis, BET measurements)
of dusts collected in EU machines couple to
maintenance activities. Comparison between metal
and carbon machine. Studies of dust chemical
reactivity with steam (couple with Surface
Specific Area estimation)
9
ITER Safety related activities

• EFDA task TW6-TSS-SEA5.1 Dust measurements and
  removal techniques (S Rosanvallon)
• diagnostics for knowledge
• CCD transport, laser extinction, embarked
  laser diffractometry, collection of dust
• diagnostics for safety monitor the dust
  quantities in the VV
• erosion (upper limit) speckle interferometry,
  erosion assessment from plasma measurements
• conversion factor evaluation from feedback
  experiments, from surface diagnostics
• removal
• use of existing or under development techniques
• integration very difficult

10
RD needed for ITER

• Diagnostics Removal
• Technical feasibility considering divertor
  design, optical accesses, reference surfaces, etc

11
RD needed for ITER

• Diagnostics Removal
• Technical feasibility considering divertor
  design, optical accesses, reference surfaces, etc

Evacuation
12
RD needed for ITER

• Diagnostics Removal
• Link between local measurements and global
  inventory?
• Is it better to use global inventory or dust in
  suspension?
• If global inventory kept, how to correlate local
  measurements (ex 0D gravimetric diagnostics or
  2D extinction) and global inventory?
• What are the studies needed before Tokamak
  demonstration? Need to have a dedicated mock up
• For dust diagnotics removal
• For dust mobilization and explosion studies
• For detritiation studies
• Mock up divertor sector including the vacuum
  vessel and a port, in a closed volume with
  possibilities to work under vacuum or inert gas

13
ITER Safety related activities

• ITER Task Force launched 20 days ago.
• Goal Draft the effort and relevant plan of
  ITER Designers to provide studies
• and design activity necessary
  to bring the DCR to the TCM approval

14
Dust prediction in tokamak

• Dust generation
• intimately linked to erosion during operation
  and disintegration of deposited layers.
• Conversion factor of deposited layers, CD, must
  be established for all phases as
• normal operation, disruptions, maintenance
  activities (He-GD with arcing, oxidation,
  venting).
• CD determined in JT60U and in Tore Supra.
• Dust collected after a full campaign is compared
  to the carbon erosion in different operational
  phases

• Cd Best estimate 10, conservative value 30.
  
• For present ITER material choice and CD10 ,
• dust production 0.5 g carbon and 0.6 g for Be
  per 400 s, full power discharge.
• For W where erosion is small.
• for all material, processes such as melting and
  droplet formation during disruption and ELMs,
• unipolar arcing, He and H embrittlement and
  blistering will dominate as already predicted in
• previous estimation (PWI processes
  difficult to predict for ITER conditions).
• More work especially on modelisation and
  crosscheck with experiments on plasma gun.

15
Dust prediction in tokamak
Dust collection characterisation Dust collection
and conversion factor, Cd(). Need of the
assessment of the total eroded PFC quantity
(normal operation, conditioning, of normal
events ) and of the total quantity of dust in
the machine (estimated from dust in situ
recollection). Dust collection homogeneity has to
be addressed too. All the EU machines concerned
but a comparison between an all metal machine
(AUG, ILW) and carbon machine must be
supported. Dust characterisation (MEB analysis,
BET measurements) of dusts collected in EU
machines couple to maintenance activities.
Comparison between metal and carbon machine.
Studies of dust chemical reactivity with steam
(couple with Surface Specific Area estimation) 1.6
Dust generation diagnostic Skinner diag in AUG,
could be used in JET? (ongoing collaboration)
16
DUST observation in Tokamak (Tore Supra)

• Dust and operation observation with CCD cameras
  (fast)
• Goal source of dust particle, transport, .

17
DUST observation in Tokamak (Tore Supra)
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Dust sampling

• Dust sampling in current machine
• Goal correlation of dust and operation process,
  maintenance etc

On going program with DIIID and
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TEXTOR Experiment with Tungsten plate
Roof graphite limiter (graphite)
Tungsten plate
Tungsten plate after exposure
G. Sergienko, V. Philipps
23
Surface morphology of melt zone W Droplets or
Dust
M. Rubel, G. Sergienko, V. Philipps
24
Melt zone Carbon dust inclusions in cavities
EDX spectra Carbon in cavities
Note It is not possible to conclude whether
inclusions contain elemental carbon or tungsten
carbide.
M. Rubel, G. Sergienko, V. Philipps
25
Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
KrF laser (248nm 27ns)
Irradiation in air of the CFC tile surface
without particle at F400mJ/cm² Cleaning effect
a superficial layer is removed
F400mJ/cm² N1
F400mJ/cm² N2
Irradiation in air of a CFC tile with C particles
26
Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
laser removal of C particles on W substrate
Purpose to get rid of layer influence on
particle removal process
redeposited carbon particles
Laser spot
KrF laser, 248nm, 27ns
Laser cleaned surface
Carbon layer
27
Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
Time Of Flight experiments Results
C particles on W substrate. KrF laser. Pfew Pa
2mm
The velocities are very high in comparison with
previous results (silica on Si) - The ablation
process is not related to explosive evaporation
of humidity or spallation - higher is the
velocity, easier could be the collection
28
Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)

• Treatment of castellation
• With direct irradiation
• Using shock waves

• Excimer or NdYAG lasers

5 ou 10
1, 2 ou 5
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
0 tir
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
1 tir à F 580 mJ/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
1 tir à F 700 mJ/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
2 tirs à F 700 mJ/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
1 tir à F 890 mJ/cm²
34
Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
5 tirs à F 890 mJ/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
1 tir à F 1,2 J/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
2 tirs à F 1,2 J/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
3 tirs à F 1,2 J/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
5 tirs à F 1,2 J/cm²
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Laser dust removal (P. Delaporte A. Vatry LP3
Luminy)
1 tir à F 1,4 J/cm²
40
Dust production during conditioning

• HeGD and W walls

Consequences on plasma operation on dust
creation.
41
Dust in situ measurements laser extinction
42
Dust in situ measurements laser extinction
43
Dust in situ measurements laser extinction
44
Dust in situ measurements GRIDS
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Dust and layer formation by laser ablation
picosecond Nd-YAG laser ?1064nm Pulse duration
50ps Repetition rate 10Hz
Mask
Lens
Vacuum chamber

• Experimental parameters
• Distance sample - target
• Gas pressure (He)
• Irradiation time

CFC tile or W sample
Silicon substrates
Sample holder
Delaporte/Vatry, CNRS LP3, Marseille
48
Carbon particles formed under vacuum
Textor Dust in magnetic confinement fusion
devices and its impact on plasma operation, J.
Winter, G. Gebauer
Delaporte/Vatry, CNRS LP3, Marseille
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Institute of Plasma Physics and Laser
Microfusion, Association URATOM IPPLM Warsaw,
Poland
Experimental arrangement
For monitoring the efficiency of the removal in
real time the optical spectroscopy was
incorporated into the set-up.
This experiment was performed in collaboration
with team from the Institute of Fundamental
Technical Problems PAS in Warsaw.
51
Dust characterization by optical
microscopy (performed in FZJ Juelich)
Dust statistics
A sample photo of dust collected on a glass plate
Dust collected on glass plates near the
target. Near gaussian grain size distribution
with mean diameter range in ?m range
52
Dust generated by laser-light impact on
co-deposits from TEXTOR Early Results
Analysis methods 3He NRA at 2 MeV and
microscopy. Irradiated targets Graphite plates
with TEXTOR co-deposits CDeuterium up to 1019
cm2 Dust collected from metal plate adjacent to
irradiated target CDeuterium 3.9 x 1017
cm2 Message Dust generated by laser-light
impact still contains fuel species thus
indicating that we move hydrogenated co-deposit
to another location in a tokamak. Important
note This single result needs verification by
other fully quantitative studies.

Structure of dust generated by irradiation of
co-deposits with laser light.
P.Gasior (IPPLM), P. Sundelin and M. Rubel (VR)
53
Dust production by ELMs
S. Pestchanyi
Simulation

• Analysis of the dust production in MK-200 plasma
  gun and JUDITH electron beam facility allows
  fitting and validation of the PEGASUS-3D code
• As an example, dust size distribution function
  produced by the ELM of 1 MJ/m2 and 500 µs has
  been simulated
• The function contains exponential distribution up
  to size 15 µm and several fibre debris of 20-200
  µm.
• Number of small particles in the distribution
  decreased 10 times with increase of their size
  on each 3 µm
• The result is reported at the ISFNT8 conference
  by S. Pestchanyi

Fibre debris
dust from the matrix
Fibre debris
Debris from experiment with NB31
Good agreement ?
54
Future activity (2008 and after) with plasma gun
Russian samples

• Formal collaboration with Russia on analysis and
  studies on samples obtained in plasma
• gun experiment (Troisk)
• BET measurements
• SEM/TEM studies
• Laser ablation and dust laser suspension with
  samples from plasma gun
• Additional measurements on mixed materials
• Modelling of plasma gun interaction with PFC
  (dust production)

55
Glow discharge recovery (Tore Supra, Douai,
Rosanvallon)
GDC1_06 BSD
GDC1_01 BSD
GDC1_05 SE
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Glow discharge recovery (Tore Supra)
Tests in Glow discharge tank for removal studies
GDC6_03 BSD
Elsewhere not so much except in the jar
GDC8_03 BSD
57
Dusty laboratory plasma (Arnas, LPIIM Marseille
Bonnin, Villetaneuse)
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Dusty laboratory plasma (Boufendi, Orléans)
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Dust injection
Dust injection (S. Rosanvallon CEA) Necessary
for diagnostic calibration Injection of
calibrated dusts (C, Ø 10 µm, 2-6 mg per
injection, from the top of the machine)
Courtesy R. Granetz (MIT - US)
60
SSA and dust
BET measurements done on plasma layers recovered
in TS and in TEXTOR (Roubin, LPIIM, Marseille)
On going comparison between TEXTOR and TS samples