Presentation to NSCX

Heinz Grote 1

Presentation to NSCXWENDELSTEIN 7-X Assembly

Max-Planck-Institut für PlasmaphysikKKS-Nr.:

1-ADDok-Kennz.:

-Txxxx.0Heinz Grote October 2007

Vacuum Systems at Wendelstein 7-X and Leak Testing during Assembly

Insulating vacuum in the cryostat

Ultra-high-vacuum in the plasma vessel

Interspace Vacuum system for multilayer bellows, double sealings, control coils, el. feedthroughs

Evacuation of the gas inlet into the plasma vessel – already working

Insulating vacuum in cryostats of the gyrotrons ECRH – already working

Vacuum system for pellet injection

Vacuum system and gas inlet NBI

Insulating vacuum ICRH

Vacuum systems for diagnostics (many)

Vacuum system for the cooling machine...

Heinz Grote 2

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Leak testing Strategy

All components to be assembled are leak tested with Helium or SF6

-before delivery (qualification of the workshops varies)-during incoming inspection-after re-work-on the assembly stands immediately after welding or mounting of the sealings-finally in an integral leak test after closing the cryostat and the plasma vessel

Where ever possible pressure gradients during testing are equal as in working condition

Where ever possible tubes and weldings of cryogenic parts are tested at temperature of LN2

Heinz Grote 3

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Leak testing Equipment (1)

All large components are leak tested with Helium in a vacuum tank

Volume: 55 m³inner diameter: 4.900 mmmax. inner height : 3.150 mmmax. height of load (crane height): 2.600 mmmax. weight of load: 7.500 kgbase pressure (< 2*10-7 mbar empty tank) (< 3*10-5 mbar loaded with W7-X coil)double–O–ring seal [Viton] with interspace pumping26 CF-ports various sizepumps: 4 x 65m³/h rotary vane pumps, 2 x 1.000m³/h roots-pumps 2 x cold traps 2 x 1.000 l/s turbomolecular pumps,

used for W7-X coil Paschen tests, He-leak tests of superconductors and He-cooling tubes on coils, support structure etc.

Heinz Grote 4

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Leak testing Equipment (2)

All joints and weldings are leak tested locally with special designed chambers or flexible bags

Variety of silicone sealed leak detection chambers made of stainless steel

Heinz Grote 5

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Leak testing Equipment (3)

Leak detection chamber made of Al sealed with Tacky Tape

Heinz Grote 6

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Leak testing Equipment (4)

Leak detection chamber made of stainless steel foil sealed with Tacky Tape

Heinz Grote 7

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Leak testing Equipment (5)

Silicone sealed stainlesssteel chamber for assuring100 % He-atmosphereduring leak testing

Temperature sensor

He- service pipe

Data logger

Leak testing at 77 K

Heinz Grote 8

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Mechanical Pumping System - Cryostat Requirements during pump down

Requirements during pump down from atmospheric pressure

Evacuation down to 1 mbar 24 hours

Evacuation down to 1*10-2 mbar 72 hours(from 1 down to 1*10-2 mbar in

48 hours)

Cooling down p < 1*10-2 mbar

Outgassing rate of the insulation 1*10-5 mbar*l/(s*m²)

Load of the insulation with water vapor 0.25 g/m²

Amount of the insulation 30 layers á 1,400 m² (conservative assumption)

Heinz Grote 9

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Mechanical Pumping System - Cryostat Working requirements, Geometry

Working Requirements

Max. partial pressure (He) 1*10-5 mbar

Max. tolerable leak (He) 1*10-2 mbar*l/s Seff >= 1,000 l/s(inside the

cryostat)

1,000 l/s in the cryostat 2,000 l/s at the port 3,180 l/s

Geometry

Ports for pumping 3 per module (= 15 overall),diameter 500 mm each

Volume approx. 500 m³

Heinz Grote 10

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Mechanical Pumping System - Cryostat Layout

Pumping set on each of the 5 modules

Gate valve DN 320 ISO F

Tube DN 320, length 4 m Bypass DN 100

TMP 2,000 l/s

Rotary vane pump 65 m³/h

Roots pump 250 m³/h )) on 2 modules only

Rotary vane pump 65 m³/h )

Heinz Grote 11

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Mechanical Pumping System - Cryostat Present status

Uwe Schultz

Heinz Grote 12

Max-Planck-Institut für Plasmaphysik, EURATOM AssociationPumping System for Plasma Vessel

- Base pressure, UHV-conditions, 10-8 mbar Turbomolecular pumps (TMP)

- Experimental, 10-5 - 10-4 mbar Hydrogen (Deuterium, Helium)

up to 10-3 mbar in the Divertor

high gas load Cryopumps,

TMP + Roots + Rotary-pumps

(3-stage mechanical pump system)

- Regeneration of Cryopumps with TMP

- Pumping through divertor gap: Cryopumps behind the target modules

TMP: 10 individual systems 1 in each divertor unitat the ports AEH and AEP

Heinz Grote 13

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Pumping System for Plasma Vessel Requirements for the Pumping System

Experiment: 3*1021 s-1 1.5*1021 molecules*s-1 ~ 50 mbar*l/s

Pressure in Divertor: < 5*10-4 mbar Pumping speed: > 100*103 l/s

cryo pumps: 75*103 l/s for H2

TMP: 25*103 l/s for H2

Pump down: ca. 1,300 m² inner surface, (1,000 m² stainless steel, 300 m² carbon, B4C)

outgassing: 1*10-7 mbar*l/(s*m²) (SS), 1*10-6 mbar*l/(s*m²) (C, B4C),

total: 4*10-4 mbar*l/s

base pressure : < 1*10-8 mbar Pumping speed: > 40*103 l/s TMP only

Heinz Grote 14

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Pumping System for Plasma Vessel Mechanical pumping system – Layout of 1 unit

Pumping gap 2,430 l/s 2,870 l/s

node: 3,200 l/s

2*1,850 l/s = 3,700 l/s

Pumping gap 1,340 l/s 1,460 l/s

1,850 l/s

Port AEH Port AEP

Total approx.: 37.7*10³ l/s

25*10³ l/s at the ports AEH alonenecessary for operation in the standard case, wherethe interaction zone of the plasma with the divertor targets is locatednear this port

Heinz Grote 15

Max-Planck-Institut für Plasmaphysik, EURATOM AssociationPumping System for Plasma Vessel

Location of the Ports

Pumping ports

Pumping ports

AEP

AEP

AEH

AEH

Heinz Grote 16

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Pumping System for Interspace Vacuum Present status

38 rectangular and oval ports with multilayer bellows (Plasma Vessel) 1 – 100 mbarto be vented only if both the cryostat and the plasma vessel are vented

40 rectangular and oval ports with double sealings (Plasma Vessel) ~ 0.1 – 1 mbar to be vented together with the plasma vessel

146 cryostat ports with double sealings ~ 0.1 – 1 mbar

to be vented together with the cryostat

3 independent roughing vacuum systems – fivefold each according to W7-X modules(dry roughing pump, valve, measuring gauge, tubes to ports DN12-20)

10 control coils will have interspace vacuum to protect the plasma vessel from water leaks

14 electrical feedthroughs – not permanently pumped

Heinz Grote 17

Max-Planck-Institut für Plasmaphysik, EURATOM Association

Control Schematic for Pumping System W7-Xbased on SIMATIC S7-400

master programmable logic controllers

part components W7-X

Olaf Volzke

central main control

W7-X