Kein Folientitel

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Max-Planck Institut für Plasmaphysik
Status of WENDELSTEIN 7-X Construction F.
Schauer on behalf of the W7-X team Max-Planck-Inst
itut für Plasmaphysik, Euratom Association,
D-17491 Greifswald

• Overview
• In-vessel components
• Plasma vessel
• Magnet system
• Outer vessel
• Ports
• Assembly of the basic device
• Periphery
• Project issues

24th Symposium on Fusion Technology (SOFT24),
Warsaw September 12, 2006
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WENDELSTEIN 7-X Overview - technical data
Major radius 5.5 m Minor radius 0.53
m Plasma volume 30 m3 Non-planar coils
50 Planar coils 20 Number of ports 299 Rot.
transform 5/6 - 5/4 Induction on axis max.
3T Stored energy 620 MJ (nom.) 660 MJ
(max.) Heating power 15 - 30 MW Pulse length
30 min Machine height 4.5 m Maximal diameter
16 m Machine mass 725 t Cold mass 392
t W7-X symmetry 5 identical modules Module
symmetry 2 flip-symmetrical halfs
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WENDELSTEIN 7-X In-vessel components

• target elements (10 MW/m2)
• baffles (1.0 MW/m2)
• wall protection (0.2 MW/m2)
• control coils
• cryo pumps
• instrumentation and diagnostics
• about 1 Million parts

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WENDELSTEIN 7-X In-vessel components - divertor
10 separate divertor units consisting of targets
and baffles, 2 in each of the 5 modules
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WENDELSTEIN 7-X In-vessel components - divertor
target module
Target
Baffle Max. P/A 10 MW/m2
1 MW/m2 Total area 19 m2
5.6 m2 Modules No. 100
20 Elements No. 890 240
Material CFC-tiles, Cu (AMC)
graphite Heat sink CuCrZr CuCrZr
Fixation HIP, EBW clamped
CFC Snecma, France Target elements Plansee,
Austria
See also poster J. Boscary
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WENDELSTEIN 7-X In-vessel components status of
manufacture

• Targets
• First target element prototypes tested to 12
  MW/m² in GLADIS test facility (at IPP)
  Flaws detected at interface between CFC
  tiles and heat sink Improved elements
  expected in October (Plansee, Austria)
• Baffles Being fabricated in the
  workshops of IPP Garching ?15 finished
• Wall protection Graphite shield
  fabricated at IPP Garching, ?20
  finished
• Double-walled steel panels fabricated by
  MAN DWE, ?25 finished
• Control coils Production started at
  Babcock Noell comp. (BNG) First coil
  delivered in October
• Cryopumps
• Fabricated at IPP Garching, ?25 finished
• Piping, feedthrough, supports, flanges
• Fabrication starting at IPP Garching,
  prototypes built, procedures qualified

See also poster Füllenbach
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WENDELSTEIN 7-X Plasma vessel
Close tolerances

• volume 110 m3
• surface 200 m2
• mass 33 t 15 t
• vacuum lt 10-8 mbar
• baking up to 150 C
• tolerances ? 2 mm (narrow areas)

See also presentation Cardella/Reich, and poster
Koppe
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WENDELSTEIN 7-X Plasma vessel plasma vessel
Plasma vessel sectors (MAN DWE)

• Plasma vessel (PV) is built up from rings
• Each half-module delivered in two sectors
• Both sectors connected after threading on
  coil 3 (middle coil of half-module)

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WENDELSTEIN 7-X Plasma vessel thermal insulation

• Al-coated glass fibre panel with MLI
• Cu-braids for connection to
• He-cooling pipe
• MLI 20 layers of crinkled, Al-coated
  Kapton foil

(MAN DWE)
Thermal insulation on a vacuum vessel sector
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WENDELSTEIN 7-X Plasma vessel status of
manufacture

• Plasma vessel Manufacture of all half-module
  sectors completed
• One half-module finished after assembly of coil
  no. 3
• First half-module thermally insulated (thermal
  insulation is performed step by step in
  accordance with coil assembly)
• Magnetic diagnostics (Rogowski and saddle coils)
  is mounted on one module

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WENDELSTEIN 7-X Magnet system

• magn. field on plasma axis 2.5 T (max. 3T)
• magn. field at conductor max. 6.8 T
• magnetic energy 620 MJ (standard)
• 660 MJ (high iota)
• 50 non-planar coils 5 types
• 20 planar coils 2 types
• CIC sc cable 243 strands
  Cu/NbTi-ratio ? 2.5
• void fraction ? 37
• operated at gt3.4 K

See also presentation Wanner, and posters
Schröder, Köppen, Birus, Bykov, Egorov, Feist
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WENDELSTEIN 7-X Magnet system - coils
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WENDELSTEIN 7-X Magnet system non-planar coil
production
Overview of Production hall (BNM, Zeitz)
Winding pack and casing (Winding ABB, Ansaldo
casing Österby, Sweden)

• Winding pack built up of 6 double-layers
• 18 turns per double-layer (one cable length)

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WENDELSTEIN 7-X Magnet system non-planar coil
production
Coil AAB18
copper stripes
casing

• Cooling by 2 He-loops in parallel,
• with 2 turns each in series
• Thermal contact via copper stripes

embedding
cooling channel
winding pack
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WENDELSTEIN 7-X Magnet system non-planar coil
production
Required coil accuracy ?B/B00 lt 2?10-4,
corresponding to 2 mm for manufacturing and
assembly
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WENDELSTEIN 7-X Magnet system planar coil
production
Planar Coil (Tesla, UK)

• Same superconductor as with NPC
• Winding pack built up from 3 double-layers
• 12 turns per double-layer (one cable length)
• Bolted casings, reinforced with 300 - 400
  shear pins per coil
• Casing cooling by 1 cooling loop contacted
  via Cu-plates to housing

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WENDELSTEIN 7-X Magnet system Cryogenic tests
on coils

• Test facility at CEA Saclay, France
• 2 cryostats for 2 coils each
• Full current tests at 5 K
• Quench test to check Ic-margin (min. 1st coil
  of each type)
• Capacity about 2 coils per month

See also poster Ehmler
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WENDELSTEIN 7-X Magnet system Paschen tests on
coils

• It cannot be excluded that during W7-X
  operation Paschen minimum
• conditions (breakdown voltage ?160 V at 0.3
  3 mbarmm) exist locally
• Powerful tool to detect hidden insulation
  defects
• Therefore all coils are tested under Paschen
  minimum conditions in air (between 0.001
  and 100 mbar) at 9.1 kV

Joint insulation failure detected by Paschen test
See also poster Petersen-Zarling
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WENDELSTEIN 7-X Magnet system status of coil
production

• Non-planar coils
• Superconductor fabrication finished
• All 50 winding packs finished
• All 50 casings cast and complete
• 38 coils embedded
• 12 coils complete
• 6 coils formally accepted
• Short circuit detected in one coil termination
• Suspicion of similar weakness in seven other
  coils,
• necessity of repair being investigated
• Systematic insulation defects in type 1 and 5
  coils being repaired
• 1 coil assembled
• Planar coils
• all winding packs finished
• 13 coils embedded
• 8 coils complete
• 3 coils formally accepted

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WENDELSTEIN 7-X Magnet system bus bars

• Superconducting bus-bar system connects
• coils
• coils and power supplies
• bifilar winding of bus bar for coil type 1 to
  avoid error fields

Development and manufacture of bus-bar system by
Research Centre Jülich (FZJ)
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WENDELSTEIN 7-X Magnet system bus bars
Bus bar connection at coil terminal
Status Bus bar fabrication started
Bus bar manufacture Weight support during
bending process using He-balloons
See also poster Rummel
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WENDELSTEIN 7-X Magnet system central support
structure

• Welded structure, 10 half-modules, supports
  the whole magnets system
• Cooled by one cooling loop per half-module
• Final machining before assembly guarantees
  exact interfaces
• Total mass 72 t
• Produced by ENSA, Spain

See also presentation Cardella/Reich
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WENDELSTEIN 7-X Magnet system central support
structure
Inboard side
Outboard side
Trial assembly of 2 half-modules after precise
machining of flange interfaces (accuracy 0.1 mm)
at Rovera comp. (Italy)
See also poster Pilopp
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WENDELSTEIN 7-X Magnet system coil support
elements
Central Support Elements (CSE) Narrow Support
Elements (NSE) Lateral Support Elements (LSE)

• Central support elements
• Coils are fixed by heavy inconel bolts to
  the central supporet structure (CSS)
• Wedges against shoulders at the CSS-side
  flanges support shear forces and torque
• Support for 5 Non-planar coil types
• 6 CSE with 9 bolts M30 each
• 2 CSE with 6 bolts M30 each
• 1 CSE with 1 bolt M90
• 1 CSE with 1 bolt M76
• 2Support for 2 planar coil types
• 4 CSE with 4 bolts M24 each

See also poster Damiani
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WENDELSTEIN 7-X Magnet system coil support
elements

• Cross section of a central support element with
  9 bolts M30
• Bolts arranged in a 3x3 matrix
• Inconel sleeves for increased elasticity
• Superbolt nuts for controlled high pre-loading

See also poster Dudek
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WENDELSTEIN 7-X Magnet system coil support
elements

• Narrow Supports on inboard side
• forces up to 1.5 MN
• sliding contact (lt5 mm)
• and tilting (lt1o).
• Al-bronce pad with MoS2 layer
• Counter-side sprayed with MoS2-spray
• Lateral Supports on outboard side
• Rigid (bolted/welded) connection
• Planar Supports
• (to fix planar coils on non-planar ones)
• Two options available, to be decided
• - sliding contact analogously to NSE- elastic
  joint

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WENDELSTEIN 7-X Magnet system status of support
structure

• Central support structure
• First CSS module interface flanges machined
• Cooling tubes being installed
• Delivery of first module beginning of 2007
• Central support elements
• First prototype tested, second prototype test
  being prepared
• Wedge welding being qualified
• Inconel bolts ordered
• Narrow support elements
• Extensive development program close to
  completion
• Production for first coil interfaces started
  (IPP workshops and sub-contractors)
• Lateral support elements
• Welded LSE design finished
• Welding procedure qualified
• Bolted HM-connection development close to
  completion

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WENDELSTEIN 7-X Outer vessel

• Outer vessel
• Volume 525 m3
• Surface 480 m2
• Mass 170 t
• Vacuum 10-6 mbar
• Port dome openings 549

See also presentation Cardella/Reich
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WENDELSTEIN 7-X Outer vessel
Outer vessel during pre-assembly (MAN DWE)
Thermal shield prototype (MAN DWE)

• Status
• 10 module half-shells welded
• 10 half-shells have been milled
• 4 half-shells equipped with about 70 of the
  domes/flanges
• first module to be delivered until April 2007

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WENDELSTEIN 7-X Ports
Port insulation prototype (MAN DWE)
OV MLI
Ports (Romabau-Gerinox AG, CH)

• Status
• 299 ports, 190 for diagnostics, 19 for heating,
• 20 for pumping and 70 for divertor supply
• 278 delivered
• Final delivery in November 2006

port tube shield
port bellows shield
OV shield
See also posters Reich, Kunkel
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WENDELSTEIN 7-X Assembly magnet modules
Mounting stand Ia magnet PV half-module
Mounting stand Ib flip-symmetric magnet
PV half-module
Mounting stand II magnet PV module
Experimental hall (final assembly)
Half-module mounting stands Ia and Ib
Metrology centre
See also poster Bräuer
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WENDELSTEIN 7-X Assembly torus completion
5 magnet modules including bus system, plasma
vessel, and central support structure
Machine base, in-vessel components,
instrumentation, current feed-through, joints,
heating systems and diagnostics
Periphery (cooling, electrics, auxiliaries,
supplies)
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WENDELSTEIN 7-X Assembly status
Assembly of coil AAB18 (type 3) on insulated
plasma vessel
NPC and PLC pre-assembly
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WENDELSTEIN 7-X Periphery Power supply,
protection, current leads

• Power supply
• All seven units of coil power supplies
  delivered (ABB Switzerland) and accepted
• Power supplies for control coils delivered
• Protection
• Nickel dump resistors delivered
• Quench detection system being developed in
  cooperation with FZK
• Prototype electronics successfully tested in
  stray field
• Current leads
• 7 pairs required
• Maximal design current 18.2 kA
• Upside-down operation
• High temperature superconductor at ?50 K
• Development, manufacture, and test contract with
  FZK

See also posters Hartmann, Schacht, Laqua, Spring
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WENDELSTEIN 7-X Periphery Refrigeration system

• Status
• Production on time
• (Linde Kryotechnik, CH)
• Comissioning end of 2008

Layout refrigerator hall
Split cold-box
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WENDELSTEIN 7-X Periphery ECRH
10MW, 140GHz cw system
View into the transmission duct
TED
CPI
TED
W7-X Gyrotrons 1 MW, cw each (Forschungszentrum
Karlsruhe, FZK)
Full performance demonstrated TED Gyr. 920 kW
for 30 min CPI Gyr. 900 kW for 30 min

• Status
• 5 out of 10 gyrotrons delivered
• Optical transmission lines up to torus hall
  completed, most loaded section tested

See also poster Braune
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WENDELSTEIN 7-X Projcet issues - Site
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WENDELSTEIN 7-X Projcet issues - Personnel
History und Plan
Status September 2006
Additional 17 contracted from companies
20 IPP Garching 10 inspectors/advisors
20 FZJ 25 FZK and IPF Stuttgart Plan
2007 Assembly personnel will be contracted
from industry
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WENDELSTEIN 7-X Projcet issues Schedule

• Schedule endangered due to coil quality
  problems (mainly defective HV insulation and
  interturn faults)
• Acceleration measures considered
• Second coil test facility
• Second assembly line up to mounting stand II

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WENDELSTEIN 7-X