Ex-1.2.5

1
Ex-1.2.5 Experiment Overview (C30C)
S.Brezinsek, P.Coad, M.Groth, J.Likonen,
G.F.Matthews, M.Rubel, A.Widdowson and all
participants in C30C and JET-EFDA contributors
2
Outline

• Goals
• Plasmaa for C30C experiment AKA Ex-1.2.5
• Achievements
• Information about post-mortem analysis foreseen
  (back-up)

• Goals
• Representative foot print of material migration
  in H-Mode with ILW
• Comparison of in-situ techniques with post-mortem
  analysis
• Document the erosion pattern, i.e. Be.
• Fuel retention with the ILW
• Gas balances vs. fuel content analysis from
  post-mortem analysis
• Role of co-deposition vs. implantation
• Evolution of wall conditions with the ILW
• Phases to be compared within C28A/monitoring
  pulse/C30C
• Mini-campaign comparable to 1 ITER pulse
  (fluence)

3
Ex-1.2.5 H-modes prior to long term sample removal

• Reliable, safe and high repetitive plasma
  scenario
• Scenario must be robust and representative for
  ILW campaigns
• Use of well developed and exploited plasma
  scenario
• with good confinement (NBI only)
• Compatible with multiple gas balance studies
• Minimise disruption risks / avoidance of MGI
• Plasma duration/repetition optimisation to
  achieve max fluence
• Aim 1000s of divertor flux during heating phase
  gt 1µm deposition at critical surfaces
• Avoid plasma movement/sweeping to avoid smearing
• Maximise the divertor time
• Plasma scenario
• Low triangularity V5_refFT_LT 2.0MA/2.0T/12
  MW/6s flattop
• Identical configuration to first plasma operation
  and monitoring pulses
• Minimised Be wall interaction gt reduce retention
• No need for ICRH

3
4
Multi-code approach to track impurity migration

• Background plasma provided by EDGE2D/EIRENE
  and/or Onion-skin model ? build on Ex 3.1.3 (for
  low-d config.)
• OSM likely to provide better model for divertor
  conditions than EDGE2D/EIRENE
• WALLDYN simulation of migration and mixing
  particularly C28a and C30c
• ERO for local Be and W migration in the divertor
  ? fuel retention mirror deposition simulations
  at KY3 location
• 3D GAPS for migration into divertor gaps and
  pumping plenum
• ASCOT for 10Be migration from IWGL

Low-d V5_REF1FT_LT on stack C High-d HT3R on
stack D
4
5
Schedule and associated experiments

• Initial session to set-up the plasma and
  characterise it with all available diagnostics
  prior to C30C (Thursday 83553-83562)
• Local 15N tracer exposure through GIM14 (Monday
  83632-83635)
• 7 sessions with exposure of mirrors on KY3 probe
  head (cause impurity influx)
• 3 AGHS gas balances (25 barl) included in the 2
  weeks
• Monday (16.7. and 23.7.) and 27.7.2012 (last day)
• Last day complete AGHS analysis of recovered gas
  from cryo panel included
• Step one LHe
• Step two LN (possibilities to measure N and ND3
  derivates)

6
Typical plasma of C30C (yes, typical indeed)
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Sessions summary

• Number of succesful plasmas 151 discharges
• Plasma duration (flattop) 906 s
• Plasma duration (divertor-time) 2400 s
• Divertor fluence per pulse 3.7x1024 ions/m2
• Divertor fluence per campaign 5.6x1026 ions/m2
• 5 disruptions above 1MA gt disruptivity 3.3
• 2 induced by 15N2 injection
• 1 by impurities from probe drive
• 1 by diagnostic failure
• Almost no W/Ni/Cr influxes without probe drive
  equipped with mirrors
• Restrictions
• Surface temperature limit 900-1020C
• Minor technical issues (power supllies, control
  systems etc.)
• BUT, machine performed very good over two weeks

8
Gas Balances
C30C
9
Impurities
Carbon
Beryllium
C30C
C30C
10
Impurities
Oxygen
Zeff
C30C
C30C
11
Prad/PNBI
C30C
12
Images
13
Experiment requirements / links to surface
analysis

• Ex-1.2.5 H-modes prior to long term sample
  retrieval with tracer injection- Main experiment
  to provide migration pattern specific to final
  H-mode phase Mass balance will be carried out
  using profiling, weighing and IBA but other
  methods also relevant Dust collection will be
  used to provide dust conversion factor link to
  Px-3.4.1 Dust detection after disruption
• - Nitrogen 15 injected prior to repeat discharges
  to mark start of experiment detection via AMS
• Also to include Px-1.1.8 First mirror plasma
  facing tests with the reciprocating probe which
  will undergo
• reflectivity and surface analysis of mirrors
  and channels after exposure
• Codes EDGE2D, OSM, ERO, WALLDYN
• Ex-1.1.2 Initial first wall Be erosion, Be and W
  material mixing and fuel retention
• All migration related surface analysis will be
  relevant but particular interest in analysis of
  indexed long term samples in the divertor which
  will have reached their 3000 pulse limit about
  now (Pulse no. 83000).
• Codes EDGE2D, OSM, ERO, WALLDYN
• Ex-1.1.4 Material migration to remote areas
• QMB shutters will be opened during Ex-1.2.5 and
  shadowed area analysed also wheels from long term
  samples to be analysedCodes EDGE2D, OSM, ERO
• Ex-1.2.1 Be tile power handling, Bx-1.2.1 Study
  of accidental Be melt events, Ex-1.3.1 Disruption
  heat loads High resolution photo survey and
  removal of dump plate tiles (TC and LTS) for
  profiling, microscopy etc.
• Codes ENDEP, MEMOS

14
Experiment requirements / links to surface
analysis
Ex-1.1.7 Divertor W erosion and ELM induced
sputtering IBA of divertor marker tiles and Mo
surface marker Codes EDGE2D, OSM, ERO Ex-1.1.5
Evaluation of fuel retention in all scenarios IBA
and TDS of deuterium content provides the
backbone of the information Codes Intention is
to repeat ITER analysis for JET which included
some ERO based assumptions Ex-1.1.9 Particle
balance for N injection and development of
removal technique D-beam NRA needed for N14
detection, N15 detected by AMS Ex-1.2.3 Bulk W
tile power handling Investigation (to be defined)
of state of spring tension etc. in marker module
removed from JET Codes Existing Efremov FE
analysis Ex-2.1.6 Characterisation of ICRF
heating with the ILW Analysis of tile 8 may be
relevant also the proposed removal of
re-ionisation, BC and HFGC tiles for fast track
ion beam analysis. If replacement tiles are
available these would be precision weighed
providing a better baseline for the
future. Codes TOPICA Monitoring of W-coating
condition and origin of W particles (UFO analysis
group) Microscopic analysis of tile surfaces and
sectioning dust collection and analysis
15
Overview of tiles to be removed in 2012

• Goals
• Investigation of
• erosion of wall and divertor tiles
• migration of impurities
• deposition
• fuel retention
• migration of 10Be
• transport of W in the divertor
• T retention diagnostics (rotating collectors,
  mirrors, QMBs, louvre clips, deposition monitors)
• Divertor tiles
• Full set of divertor tiles
• 25 µm and 10µm W/Mo
• IWGL, OPL, dump plate
• 7 µm Be/ 2 µm Ni
• 10Be tile
• Tiles for 10Be tape testing already identified

16
Analysis plan of tiles in 2013

• Associations
• CCFE (tile profiling, IBA analyses)
• TEKES, Finland (coring, sectioning, SIMS,
  optical microscopy)
• ITN, Portugal (IBA analyses)
• IPP, Germany (IBA analyses)
• VR, Sweden (microbeam analyses, SEM)
• MEdC, Romania (AMS for tritium, XPS, XRD, X-ray
  tomography)
• AEUL, Latvia (FCM for tritium)
• FZJ, Germany (TDS)
• MIT, USA (NRA using deuterium beam) ? subject to
  formal agreement
• Methods
• AMS Accelerator Mass Spectrometry
• FCM Full Combustion
• IBA Ion Beam Analysis
• NRA Nuclear Reaction Analysis
• SIMS Secondary Ion Mass Spectrometry
• SEM Scanning Electron Microscopy

17
Additional analysis proposed following C28-30
results

• Specific issues from ILW operations to be added
  to planning
• Erosion due to ICRH heating origin of W sources
  
• Post-mortem surface and metallographic analyses
  or fast track IBA if no spares
• Tiles affected HFGC, A , B and re-ionisation
  tiles
• Not currently in shutdown plan so a change
  request will need to be raised.
• Disruption damage / melting to dump plate tiles
  at top of vessel
• Thermocouple tiles 2A1,2,3,4,5,6,8 are in the
  current shutdown plan for replacement
• It is proposed that these are dismantled for
  closer analysis of the melted areas to get a
  better estimate of the volume of melted material
  and melt characteristics. At the same time a
  more complete analysis of deposition can be
  obtained.
• Nitrogen 14 profile in the co-deposited layers
  due to N2 seeding experiments
• Post-mortem analyses using NRA with D beam of
  existing cored samples (not possible by other
  means)
• Anomalies revealed by high resolution photography
  in vessel
• Prompt review of high resolution in-vessel
  photographic survey is recommended on the basis
  of this change requests may be made for temporary
  removal of tiles for fast track IBA

18
Analysis plan of tiles in 2013

• IWGL, Dump plate, Wide poloidal limiter tiles
• IWGL 5 Be tile pieces in each right wing,
  right middle, centre, left middle, left wing
• Dump plate single Be piece
• WPL 7 Be tile pieces in each right wing,
  right middle, right intermediate, centre,
• left intermediate, left middle, left wing
• Coated with 2-3 µm Ni and 6-8 µm Be
• Tiles have been pre-analysed by IBA (CCFE),
  weighed and tile profiled (CCFE) before
• mounting in JET to facilitate measurement of
  erosion after exposure
• Analysis plan
• Remove from Inconel backing plate
• Tile profiler to look for gross erosion (CCFE)
• Re-measurement by IBA (of whole tile pieces if
  possible) to look for
• erosion/deposition/H-isotope retention
• Part off individual castellations with milling
  machine (8x8x8mm each, JOC)
• Further analysis for erosion/deposition/H-isotope
  retention (selected from requests to TFFT)
• such as
• Further IBA on small samples
• SIMS

19
Analysis plan of tiles in 2013

• Inner Wall Cladding
• A toroidal distribution of small Inconel inserts
  sachets
• 9 of these prepared at IPP, Garching with Be and
  W coatings on half of each sachet
• 5 coated with Be at General Atomics, via UCSD
• Samples have been pre-analysed by IBA (IPP,
  Garching/CCFE) before mounting in
• JET to facilitate measurement of erosion
  after exposure
• Analysis plan
• Remove from Inconel IWC plate (which will be
  refitted with spare sachet) (JOC)
• Re-measurement by IBA to look for
  erosion/deposition/H-isotope retention
• Further analysis for erosion/deposition/H-isotope
  retention (selected from requests to TFFT)
• such as
• SIMS
• Sectioning
• SEM
• TDS

20
Analysis plan of tiles in 2013

• Divertor tiles
• Marker coated tiles 1,3,4,6,7,8 in Modules 2 and
  14
• Standard divertor tiles are CFC coated with 2-3
  µm Mo 18-22 µm W (total 20-25 µm)
• Marker tiles to be exchanged coated with 2-3 µm
  Mo 12-14 µm W 3-4 µm Mo
• 3-4 µm W (total 20-25 µm)
• Tiles have been pre-analysed by IBA (IPP,
  Garching) and tile profiler (CCFE) before
• mounting in JET to facilitate measurement of
  erosion after exposure
• Analysis plan
• Remove metal fastenings from tiles (JOC)
• Tile profiler to look for gross erosion (CCFE)
• Re-measurement by IBA (of whole tile pieces if
  possible) to look for
• erosion/deposition/H-isotope retention
• Cut series of 17mm diameter core samples from
  tile (TEKES)
• Further analysis for erosion/deposition/H-isotope
  retention and for interdiffusion, alloying,
• carbidisation etc (selected from requests to
  TFFT) such as
• Further IBA on small samples
• SIMS
• Sectioning