GAPS ON THE DIVERTOR CASSETTES

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GAPS ON THE DIVERTOR CASSETTES
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The divertor is split in 54 modules or cassettes
. These 54 divertor cassettes are positioned at
the bottom of the vacuum vessel and placed on two
accurately aligned toroidal rails. The nominal
gap between cassettes is 10 mm , required to
avoid contact between cassettes when they deflect
under the effect of induced electro-magnetic
forces during disruptions .
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• There are requirements to introduce cut-outs in
  the Plasma Facing Components in order to
  accommodate several of the diagnostic systems
  and probes allocated to the Divertor Ports
• There are as well requirements to locate
  wave-guides , Langmuir probes and Bolometers on
  the side of the cassetes . This implies
  increasing the gap between Plasma Facing
  Components in order to absorbe the extra width of
  these components and still ensure 10 mm gap
  between adjacent cassette components.

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Divertor Port Distribution
There are six Ports in which Diagnostics are
allocated
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10 mm Parallel Gap between Cassettes
In front of each Port there are three cassettes
into which diagnostic equipment can be installed
Central Cassette (
Central in Port ) or Diagnostic Cassette
Side Cassette ( Either Side of Central Cassette )
or Instrumented Cassette

• A Diagnostic Cassette (x6) (central in port)
• An Instrumented Cassette (x10) (either side of
  central cassette,except 04)

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Port 2
Cut-outs for LVNC in Blanket Module 18,
Divertor Outer Target not affected
Lower Vertical Neutron Camera (LVNC )
Impurity Monitor
Request to Increase gap from 10 to 20 mm to
improve light collection from Impurity Monitor
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Port 8
Increase Gap to 30 mm to fit Interferometer
system and still keep 10 mm nominal gap
Interferometer 20 mm wide
Laser Induced Fluorescence
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Port 10
Divertor X-Point LIDAR Thomson Scattering
Cut-out required for X-Point Thomson Scattering
emission and reception system
Local cut-outs to Increase gap locally from 10
to 38 mm to obtain light collection for
Divertor Outer Leg Thomson Scattering system
Outer Leg Thomson Scaterring
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Port 14
Increase Gap to 30 mm to fit Waveguides of
Reflectometer
Reflectometer 20 mm wide waveguides
Plate Erosion
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Port 16
No requirement for increased gap or for cut-out
VUV Impurity Monitor
IR Thermography
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Cassettes 06, 14, 24, 32, 42 50
Cut-out required in Outer Target
In Vessel View Gass Discharge System Probes
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Additional requirements to increase the gap
between cassettes due to the bolometers .
Cassettes affected and increase of gap requested
under revision.
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Additional requirements to increase the gap
between cassettes due to the Langmuir Probes .
Cassettes affected and increase of gap requested
under revision.