Presentation to NSCX

1. WENDELSTEIN 7-X Assembly Max-Planck-Institut für Plasmaphysik Presentation to NSCX KKS-Nr.: 1-AD Dok-Kennz.: -Txxxx.0 October 2007 Heinz Grote 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. Leak testing Strategy Max-Planck-Institut für Plasmaphysik, EURATOM Association • 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. Leak testing Equipment (1) Max-Planck-Institut für Plasmaphysik, EURATOM Association All large components are leak tested with Helium in a vacuum tank Volume: 55 m³ inner diameter: 4.900 mm max. inner height : 3.150 mm max. height of load (crane height): 2.600 mm max. weight of load: 7.500 kg base pressure (< 2*10-7 mbar empty tank) (< 3*10-5 mbar loaded with W7-X coil) double–O–ring seal [Viton] with interspace pumping 26 CF-ports various size pumps: 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. Leak testing Equipment (2) Max-Planck-Institut für Plasmaphysik, EURATOM Association 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. Leak testing Equipment (3) Max-Planck-Institut für Plasmaphysik, EURATOM Association Leak detection chamber made of Al sealed with Tacky Tape Heinz Grote

6. Leak testing Equipment (4) Max-Planck-Institut für Plasmaphysik, EURATOM Association Leak detection chamber made of stainless steel foil sealed with Tacky Tape Heinz Grote

7. Leak testing at 77 K Data logger He- service pipe Temperature sensor Silicone sealed stainless steel chamber for assuring 100 % He-atmosphere during leak testing Leak testing Equipment (5) Max-Planck-Institut für Plasmaphysik, EURATOM Association Heinz Grote

8. Mechanical Pumping System - Cryostat Requirements during pump down Max-Planck-Institut für Plasmaphysik, EURATOM Association • 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. Mechanical Pumping System - Cryostat Working requirements, Geometry Max-Planck-Institut für Plasmaphysik, EURATOM Association • 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 port3,180 l/s • Geometry • Ports for pumping 3 per module (= 15 overall), • diameter 500 mm each • Volume approx. 500 m³ Heinz Grote

10. Mechanical Pumping System - Cryostat Layout Max-Planck-Institut für Plasmaphysik, EURATOM Association 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. Mechanical Pumping System - Cryostat Present status Max-Planck-Institut für Plasmaphysik, EURATOM Association Uwe Schultz Heinz Grote

12. Pumping System for Plasma Vessel Max-Planck-Institut für Plasmaphysik, EURATOM Association - 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 unit at the ports AEH and AEP Heinz Grote

13. Pumping System for Plasma Vessel Requirements for the Pumping System Max-Planck-Institut für Plasmaphysik, EURATOM Association 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. Pumping System for Plasma Vessel Mechanical pumping system – Layout of 1 unit Max-Planck-Institut für Plasmaphysik, EURATOM Association Port AEH Port AEP 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  25*10³ l/s at the ports AEH alone necessary for operation in the standard case, where the interaction zone of the plasma with the divertor targets is located near this port Total approx.: 37.7*10³ l/s Heinz Grote

15. Pumping System for Plasma Vessel Location of the Ports Pumping ports Max-Planck-Institut für Plasmaphysik, EURATOM Association AEH AEP AEP AEH Pumping ports Heinz Grote

16. Pumping System for Interspace Vacuum Present status Max-Planck-Institut für Plasmaphysik, EURATOM Association 38 rectangular and oval ports with multilayer bellows (Plasma Vessel) 1 – 100 mbar to 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. Control Schematic for Pumping System W7-Xbased on SIMATIC S7-400 Max-Planck-Institut für Plasmaphysik, EURATOM Association central main control W7-X master programmable logic controllers part components W7-X Olaf Volzke Heinz Grote