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LHC Cryogenics Status and perspectives

LHC Cryogenics Status and perspectives. S. Claudet on behalf of Cryogenic group. Content. Summer to September 2008 Present activities and shut-down constraints Consolidations towards availability: Machine related hardware Utilities Cryogenic system Power permit (s)

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LHC Cryogenics Status and perspectives

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  1. LHC CryogenicsStatus and perspectives S. Claudet on behalf of Cryogenic group

  2. Content • Summer to September 2008 • Present activities and shut-down constraints • Consolidations towards availability: • Machine related hardware • Utilities • Cryogenic system • Power permit (s) • Organisation of resources • Summary LHC MAC 24 - Cryogenics

  3. First beams around LHC Simultaneous Cryo start/maintain All sectors at nominal temperature Short in connection cryostats and repairs UX85 Ph1 works Open Days Christmas and water maintenance shut-down Cooling sectors + Cryo tuning + Powering activities LHC MAC 24 - Cryogenics

  4. LHC Cryogenics for D-day We did it ! Thanks to contributors and partners, luck was with the braves !!! LHC MAC 24 - Cryogenics

  5. Not much margin !!! UX85 Ph1 works Transformers 1,2 3,4 Air leak Oil leak Oil filters Tu Air CC 24V LHC Beams around the ring for the 1st time ! LHC MAC 24 - Cryogenics

  6. Bearings/Drive communication problems Re-connection at lower pressures (70-55-30mbar) 1.8K Units: Global significant progress ! Two Months before manual stop ! Better than 2wks MTBF Spring’08 ! LHC MAC 24 - Cryogenics

  7. LHC Cryogenics Autumn’08 Repairs Consolidations Maintenance Cryo tests: 2 sectors on one Ref.+ calorimetry Floating, TTMaxMAG<130K Warming-up by controled degradation of vacuum LHC MAC 24 - Cryogenics

  8. 1.8 K Refrigeration Unit Ex-LEP 4.5 K Refrigerator New 4.5 K refrigerator 1.8 K Refrigeration Unit Warm Compressor Warm Compressor Warm Compressor Warm Compressor Station Station Station Station Surface Cold Box Upper Cold Box 4.5K 15 mbar Shaft Lower Cold Box Cavern Cold Compressor Cold Compressor Interconnection Box box box Distribution Line Distribution Line Powering tests Powering tests Tunnel Magnet Cryostats Magnet Cryostats LHC Sector (3.3 km) LHC Sector (3.3 km) Two sectors on one cryoplant ≈ 10% capacity left for dynamic loads, after specific adjustments made ≈ 5MW of power input, instead of 8MW (2x4MW) Competitive for recovery after stops (<10hrs for CC, <24hrs after power failure for 2 sectors) Not valid for large transients, but an interesting feature for low beam loads, or validated fall-back scenario if serious problems with a refrigerator LHC MAC 24 - Cryogenics

  9. Warm-up by controled degradation of vacuum 19Sept’08 Warm-up of 12 Sectors progressively emptied, operation “75K stand-by” mode for protection of PIM’s and minimised thermal expansions Magnet emptying for maintenance or warm-up for consolidations LHC MAC 24 - Cryogenics

  10. Remote storage Helium inventory and remote storage 8 t Storage: 57 t 45t Ghe (Max/50t) 12t LHe Losses 34: 8 t Remote: 23 t (virtual storage) 8 x 16 t = 128 t LHC: 48 t (3 sectors) Only up to 5 sectors empty in 2008 (3 sectors used as storage) Spring 2009: 25t back + 10t new LHC MAC 24 - Cryogenics

  11. Consolidations: Machine related • Connection cryostats (56) • Level gauge piping for stand-alone magnets • On warm sectors, or • When temporary local warming is possible, or • On most delicate type (MQY) • Y line for bayonet heat exchanger tubes (34-78-81) when sector warm=> 34 only • Superconducting link at P3 (DSLC) • Heat sink (Cu leads) on some triplets (t.b.c) LHC MAC 24 - Cryogenics

  12. Levels for stand-alone magnets Since summer 2008: - Case by case compromise found - Global pressure stability required For 2009: Pipe work to be consolidated when possible LHC MAC 24 - Cryogenics

  13. Cable layout Layer 1 (inner) Wires 1-10: Layer 2: 11-26: Layer 3 (outer layer) 27-48: Not OK OK The DFBLC and DSLC in UJ33 Cryo instrumentation tuned for larger Helium mass-flow => Stable operation now at 9-10 g/s (w.r.t 4.5 g/s before) Improvement for powering above expectations ! LHC MAC 24 - Cryogenics

  14. Towards more stable utilities • Electricity: • 3.3kV input Power, 400V distribution, 24VDC units • Spares or fall-back solutions being implemented • Cooling water: • Many consolidations identified and launched • Main water pumps: MTTR ≈ Cryo tolerance … • Controls: • Communication cards and network being consolidated • Insulation vacuum: • Interlocks for “catastrophic rupture” to be simplified • PLC’s to gauges to be put on UPS … LHC MAC 24 - Cryogenics

  15. Cryogenics main consolidations • Mecanics: • Repairs of few leaks into cold-boxes insulation vacuum • Change of 1 control valve for 1.8K units when possible • Change of about 100/2200 valve popets • Instrumentation • Instrumentation on electrical feed boxes (TT, CV) • Tuning of valve positioner dynamics • Correction of Non-Conformities • Automatisms: • 2nd generation of logic (simplified) for tunnel • Standardisation of procedures for interconnection of sub-systems • 1.8K units LHC MAC 24 - Cryogenics

  16. Power permit (s) Often ≈ 80% availability on a sector, sometimes ≈ 90%, much more expected! • Conditions to be reviewed and possibly relaxed based on experience: • Cryo maintain (slow abort) to really protect equipment • Cryo start (start interlock) if powering ramp could be aborted, not to illustrate cryo stability • Analysis to be made for sets of pre-defined optics requirements: • Orbit correctors, decapoles, spare current leads not always necessary … LHC MAC 24 - Cryogenics

  17. LHC Cryo OP Organisation of resources • Cool-down of 8 sectors: • Should be OK with structure in place • HWC of many sectors in parallel: • Since mid Jan’08, operators up to 22h and Saturdays • Since Spring’08, two shifts (week) and Saturdays (day) • First beams: • We do not have CERN staff (alone) for any kind of shift • Various type of shifts possible via our industrial partner, with CERN experts and local control rooms (day time) in back-up • After July 2009: • End of present operation contract, with in-sourcing plus “Field Support Unit” as reference solution, to be re-evaluated end 2008 Winter shut down Sept. to Nov’08: 2 x (3x8h-7d/7d) in CCC Clearly a must at the beginning! New operators recruted (3 + 2 soon) one year before the end of contracts of 1st generation of operators (4), allowing to organise shift work in 2009 No significant progress yet with collaboration with other teams LHC MAC 24 - Cryogenics

  18. Summary • LHC Cryogenic system has been put in operation with success and was “ready” for D-day • Test programs were conducted to improve our understanding and tuning of sub-systems • Consolidation programs Utilities-Cryo-Machine are being implemented during this winter shut-down • Operation with shift (1 x 5x8) to start spring’09 and possibly a bit more, with industrial support to help for big transients and possible others for specific cases LHC MAC 24 - Cryogenics

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