LHC Cryogenics: “From cool-down & HWC to operation with beam” S. Claudet, for LHC cryogenics Extended LTC, 3 Mar’08

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Content How to operate up to 8 sectors together Recovery after a quench: how much time does it take? Is expert intervention required? How can this be improved? Equipment folder: tests results, handling of non- conformities, performance below specs, machine as commissioned vs. machine as nominal Alarms/signals/SW available in CCC Piquet/Experts availability 3. Resources 2. Availability 1. Technical issues 4. Tools & Resources

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Major Technical issues (1/2) Being implemented before HWC: –DFB’s: level gauges, anti-condensation, valves and filters –Stand-alone levels: short term solution being applied (evolution ?) No remaining technical limitations so far To be tested during HWC: –Re-connection of line B (pumping) below 50 mbar –Quench lines at odd points in case large number of cells would quench –Heat loads, to quantify the remaining capacity for beam induced loads w.r.t previsions Time slots to be allocated at best globally

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Major Technical issues (2/2) Identified, not yet launched: –P8 ex-LEP 4.5K refrigerator: subcooler to be replaced –QRL line D temperature: 20K is an average, not yet all-along –UX85: Tolerance to single-events for PLC’s and electronics Most of necessary hardware available, time slot to be decided Identified, but to remain for some time: –Helium inventory: from 20l/m to > 25l/m –Line Y heat-exchanger: if discovered after cool-down (1, 3, ?) –Stand-alone levels: long term solution ? –Robustness of some electronic cards and features ? Direct impact on recovery time, not on performance for the 1st run + Time slots for preventive maintenance, or wait and repair strategy ?

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Availability: From 7-8 to others For future sectors, we maintain our objectives with work on recovery time But as well we try to give Cryo Start/Maintain earlyer ! 7-8 (2007): 85% for LSS (>1st May’07) 66% for ARC (>1st Jun’07) Target 4-5: 90% for LSS 80% for ARC ELQA Cryo Maintain ARC: 63% (Since 14Jan08) Stand-alone levels DFB’s valves Cryo Maintain LSS: 70% - 93% (Since 21Jan08 or 01Feb08) LHC 45: MTBF: 11 days - MTTR: 48 hrs

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Recovery Time after Limited Resistive Transitions More than 14 cells or full sector: recovery up to 48 hours In case of fast discharge (even w/o quench): 2 h recovery (heating due to eddy currents). (Predictions at design stage) Achieved or achievable Now: 2 to 3 times slower

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Recovering a quench 2. Larger He Qty released (criteria!): > Pre-cooling required before LHe re-filling > Perturbation of global process, to be done by expert Alternative 1. considered less perturbating for HWC, ideas to make it automatic and 10 kA 1. Small He Qty released: > Usual 1.9K cooling valve at max. opening > Self adapting and global process kept OK

S. Claudet - 3rd March 2008LHC Cryo - extended LTC LHC Cryogenics availability Rough ideas for discussions Reminder: a cryogenic system takes time (hours) to recover any kind of stop (seconds) Target for HWC Target for LHC operation considering independent origins

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Availability MTBF: –Less perturbations due to EL or CV systems –First results of global effort of teams to work together  To be further improved for beams to circulate one day! MTTR: –Experience so far with cold compressors helped pump-down to 15mbar to be successful at each try! –Conservative approach to prevent spoiling 15mbar conditions (2hrs more versus 2 days lost!) –Ideas to make it more automatic are being tested –We will never compensate the time delay for Y lines ! Quench recovery: –A simple and safe solution is being studied for automation

S. Claudet - 3rd March 2008LHC Cryo - extended LTC No Tel SdC P2 - P4P6P8 - P18 U. WagnerG. FerlinF. Millet JP. Lamboy (P2/2-3) S. Junker (P4/3-4) + C. Parente (Apprentissage) L. Herblin (P18/1-2) A. Eychenne (P2)G. Vincent (P6)E. Lussi (P18) N. Navion (P4)E. Millet (P8) Affectations LHC Cryo CRG-OA LHC Cryo OP P18P2P4P6P M. Soubiran (Analyse fonctionnelle) Team Leader: S. Claudet + Industrial partner teams in local control rooms (≈ 23 personnes ALLS) + 2 posts (C) identified, not yet through !

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Working periods CERN staff: –Normal working hours + overtime when needed –On-call service: 1 Operator (direct) + 1 Engineer (back-up) Now: mostly to guarantee safety and helium inventory –Expert assistance in CCC for specific tests Industrial partner: –Normal working hours + overtime when needed –On-call service: 1 Operator (direct) + 1 Operator (direct) –Afternoon shifts (14h-22h): 2 Operators, mostly for LN2 trucks –Saturdays: 2 Operators, for LN2 trucks and interventions HWC activities already possible up to 22h and Saturdays ! Investigations for 1 Operator in CCC (2 shifts) after logistics with LN2 trucks

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Resources Cool-down of 8 sectors: –Should be OK with structure in place HWC of many sectors in parallel: –Already now, up to 22h and Saturdays –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 as reference solution, to be re-evaluated in 2008

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Challenge for Spring’08 Preparing tools to help having a quick global overview, and identify what needs to be delegated to local tuning teams or consolidated

S. Claudet - 3rd March 2008LHC Cryo - extended LTC Summary Technical issues treated to allow HWC and first LHC beams Methodology for cryogenic commissioning in place Learning curves for transients on the good way, with automation in progress and team experience growing Work started to safely improve “Cryo start” statistics and availability OP team structure adapted in January 2008 to face parallelism (x8) Imminent presence in CCC (2 shifts during week)  We can adapt and redeploy resources until July 2009, (incl. 2 x 5x8)  Longer term future to be consolidated