Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
1/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
• Context : The impact of these “special” interventions• In-situ work or cryomagnet replacement ?• Reasons for an intervention:• Vacuum related issues• Cryogenics related issues• Electr(omechan)ical integrity • Beam optics• DS Collimators•Miscellaneous• How many cryomagnets exchange? Spares?• The special interventions team and the work location• Conclusions24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
2/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Context : The impact of these “special” interventions
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
Limited space
Shared human resources
Limited time (Minimise the impact on the shutdown duration)
Interventions on the same circuits
3/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
In-situ work or cryomagnet replacement? (1/2)
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
Many operations with > 6 different teams:IC, ELQA, VSC, Survey, BLM, QA,… and an heavily interleaved sequence Actions on circuits sometimes not sectorised over 3 km (beam lines, cryo lines) Also technical and schedule interferences
Sequence touches 4 half cells (216 m)
4/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
In-situ work or cryomagnet replacement? (2/2)
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? All cryomagnets are not equivalent:
By increasing difficulty:- Standard cryodipole- Standard SSS without jumper- Standard SSS with jumper- DS(6kA) cryodipole- DS(6kA) SSS without jumper- DS(6kA) SSS with jumper- Cryoassemblies connected to a DFBA- DSs @P6 are specific (No Q7, Jumper on Q10 instead of Q9 …)- LSS ? (Variable-No rule)
For a “standard” cryodipole:Duration: 6 weeks from opening of IC to reclosure if non-stop work
considering one extended day (12 hours) in one shiftWorkload: About 600 man hours per standard cryodipole replacement
Welders, mechanics, electromechanics, ELQA, QA, leak tester
Less if consecutive magnets5/23
J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
Vacuum related issues (1/3)
24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
Leaks
Subsector is localized but not the exact leak originTime is required before opening & during the shutdown for leak detection/localisationPresent status : about 20 leaks / 11 are important / 1 is critical (A27L4)Usually, repairable in-situNew leaks could appear before the next long shutdown or be created by the warm-upTypical sequence: Leak detection / confirmation on each subsector during warm-up Opening of the interconnections Leak localisation (Requires circuit pressurisation: Safety & Coordination) Leak repair Repair validation
Conclusion: Work on all leaks to improve the situationOnly one cryomagnet could have potentially to be exchanged (A27L4)
6/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
Vacuum related issues (2/3)
24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
PIMs :-Buckled during warm-up : based on last warm-up after SSS displacement : ≈ 18 (RF ball test)-Heavily damaged : ≤ 10-Preventive replacements :
+ Arc extremities18/32 in baseline+ Not in the baseline: QQBI and QBQI close to a SSS with vacuum barrier (356 or 862) to decrease the risk of bucking in case of local warm-upConclusion:
About 45 PIMs are considered to be replaced
Low risk of failure in case of local warm-up that could require venting to replace the failed PIM and a subsequent scrubbing run (≈ a week)
A non-conformity of the RF fingers during their fabrication can lead to a failure of the component during the warm -up
7/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
Vacuum related issues (3/3)
24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
Nested bellows:About 55 small damages identified / 2 are heavierInspection will be carried out (VSC) to confirm that they do not need to be changed.Useful only in case of cryogenics operation error.Can survive a few accidental cases No replacement plannedBeam screens: One with leaking cooling capillary (S81): 2 were bypassed for symmetry No need for intervention Wrong type of beam screen (saw-teeth profile): 12 MBs/2 SSSs mainly in 34This could be an issue for cryogenics and electron cloud build-upVSC follows that with ABP & CRGÞNo replacement planned so far but impact in terms of resources described later ; Would mean 14 cryomagnets more to remove and surface work
QBQI.10L5, NCR 831037, nested bellows V2
8/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Consolidation of SAM Helium level gauges
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? Cryogenics related issues (1/3)
Details in ECR: LHC-LQN-EC-0001Level gauge reading was not stable
Existing capillary replaced by a larger metal hoseIt is planned to consolidate the 2 remaining ones (Q6R2, Q6L8) during the long shutdown
Repair of leaking Y-linesIt is planned to consolidate the 2 known cases (S78:17-19R7 & S81:19-22R8) during the long shutdown
9/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Installation of Pressure Relief Devices
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? Cryogenics related issues (2/3)
To be installed on cryodipoles (DN200) during next shutdown in 23, 45 (part), 78 & 81: ≈ 600 units and on 2 SAM (DN160)
10/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Triplets braid
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? Cryogenics related issues (3/3)
Cryo-InstrumentationAccess will be given to allow cryo-team to intervene
L1 R1 L2 R2 L5 R5 L8 R8NCR 982513 982506 982524 982518 982511 982525 982512 982517Action Remove Install Remove Install Install Remove Remove InstallStat./Prior. 1 Done 2 2 Done 1 2 2
3 weeks of work per triplet (not full time)To be done in second part of the shutdown (ALARA)Priority 1 are included in the baseline (HL exp)Priority 2 will be done if time is available 11/23
J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
Consolidation of the Connection Cryostats
Electr(omenchan)ical integrity (1/4)
The proposed plan is :•Measure and if necessary consolidate the CC 11L8•Consolidate the CC in 11L3 (If DSColl. not installed) & 11L1•Measure / inspect all the CCs to check no displacement
Details in ECR: LHC-LE-EC-0003
Risk of short to ground on main BB due to supports displacementAddition of extra insulation to go up to ultimate energy
12/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
Special splices:-600 A: in 78 : sampled inspections -6kA:(see presentation by F Bertinelli, LHC Splices Task Force)Opening for inspection of line N boxes not fully documented (sampling) and/or 8L and/or possible outliers found during splice mapping for inspection and possible consolidation-13 kA (DFBA): access and one specific case
Electr(omenchan)ical integrity (2/4)
Circuit issues (Open, high R)
Circuit Sector RemarkRCO.A81B2 81 Circuit is openRCBH31.R7B1 78 Circuit is too resistiveRCOSX3.L1 81 Circuit is open
• Investigation will be carried out• Some tests could be required before warm-up• Repair procedure to be defined• New issues could occur
13/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? Cryomagnets issues: High internal splice resistance
Electr(omenchan)ical integrity (3/4)
No change of the splice resistance even after this extensive fatigue test in SM18
To be analysed in the LHC machine in details
From Zinur Charifoulline
Why should a magnet with a high internal splice resistance be replaced ?
Scheme from C Scheuerlein
Note small value !
QuadsDipoles
Not for cryogenics reason (OK for extra heat load) Not for electrical reason For mechanical reason# to exchange (proposal) + 8 dipoles (4A&4B) in S12&23) & 1 SSS (in S34) + Test programme Reduction by 50 % of inner resistance 14/23
J.Ph. Tock
To be disconnected for DS Coll installation
Technology Department
Chamonix 2011 LHC Performance Workshop
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? Cryomagnets issues
Electr(omenchan)ical integrity (4/4)
# to exchange (proposal)
+ 5 dipoles15/23
J.Ph. Tock
Dip ID Sector Issue Status1007 78 Breakdown at 1.6 kV Diagnostic (IFS) then exchange if not repairable in tunnel1263 67 IFS wires Inspect then likely repairable in the tunnel1372 12 IFS wires Inspect then likely repairable in the tunnel2007 78 QH likely damaged Diagnostic (TDR) then advisable to exchange2138 45 QH likely damaged Diagnostic (TDR) then advisable to exchange2214 45 QH likely damaged Diagnostic (TDR) then advisable to exchange2395 12 IFS wires Inspect then likely repairable in the tunnel2413 12 Weakness in 3 HF QH Advisable to exchange3708 23 IFS wires Inspect then likely repairable in the tunnel
Has also a high inner splice resistance
Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
Beam optics
24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
Wrong SSS types (S34): [LHC-LQA-EC-0004 M Modena] • 2 circuits are degraded (one is missing) (Q23,27,28,32 R3): [2 with jumpers]• MQS: Q23,27• MO: Q28,32Q5L8 : Warm corrector installed (78)
• To be replaced by a new Q5 L8
Priority to be given to RQS circuit (ABP input)
# to exchange : Proposed baseline : 2 (Q23R3, Q27R3)
16/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
DS Collimators (See previous presentation by V Parma)
24th of January 2011
What to do in 2012/13 if you are not consolidating splices ?
# to “exchange” :Baseline : 32
32 cryo-assemblies to be:• Disconnected• Brought to surface• Reworked• Reinterconnected
IC to cut # 28 Some special ones (DS)
Jumpers to cut # 6 5 to reconnect (Cryoextensions)
Cryostats to move # 26 7 Longitudinally / 6 RadiallyDFBA to move # 2 Affect also warm regionDS Collimators # 4 TCRYONew cryostats # 3 1 CC’ of ≈ 9 m lengthJumper longi motion # 4 DFBA & Q7: Not standardModif line N # 6 (8)
Involves surface work
17/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
Miscellaneous
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
BPM cables checks and repairsRP samples : See ECR LHC-LI-EC-0001 for detailsRecover and measure some of them ;New ones to be installed ?New issues appearing before long shutdownDetected during operation (Higher L, E, time…)Non-conformities generated during the long shutdown
18/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
•How many cryomagnets to exchange? Spares?
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
19/23J.Ph. Tock
MB SSS Tot1 8 1 9 High inner splice resistance To be confirmed after tests/study2 5 0 5 Electrical integrity Between 1 and 93 0 2 2 Beam optics Restoration of MQS in 34 only4 1 0 1 Leaks Depending on repairability5 0 0 0 Reversed beam screens Not considered but could be 14 !6 16 8 32 DS Collimators Not counted in total
TOTAL 14 3 17 DS Coll excluded
# Quantity Reason Remark
For MBs, spares should be available.If reversed BS to be changed, this will have to be done in SMI2
For SSSs, 3 should be available before the start of the shutdown (2012)A balance between time saved and procurement of new cryostat components needs to be done Work at the surface will be required to rework the extremities of removed cryomagnets
Technology Department
Chamonix 2011 LHC Performance Workshop
The special interventions team
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ? Function At CERN Missing Total WorkCoordinator 0.5 0 0.5 External interfacesTeam leader 1 0 1 On-siteExpert welder 1 1 2 All types of weldsWelder 0 1 1 AssistantWelders Automatic and manual (including QA,…)Expert electromechanic 1 0 1 Ultrasonic weldsElectromechanics 1 4.5 5.5 Electromechanics (Assistance in US welding, electrical insulation, line N...)Main splices Soldering, shunting,…Expert mechanics 1 0 1 Specialist in cutting (all types)Mechanics 0 4 4 Opening/closure of IC, thermal insulation, assistance in cutting,…Logistics 0.5 1 1.5ELQA Krakow Collaboration: Not in totalQA inspector 0.5 2 2.5 Endoscopy, electrical checks, traceability, inspections..Leak Test
TOTAL 6.5 13.5 20 < 1/3 experienced staff !!!
Train
TE-VSC
TE-MPE
EN-MME
Surface work (SMI2, 180) to be considered in addition. Change of cryomagnets with reversed BS would strongly impact [+ 5.5 FTE]
Ratio of experienced staff 20/23
J.Ph. Tock
*Based on 12 months between opening of the first IC and closure of the last one
Technology Department
Chamonix 2011 LHC Performance Workshop
The work location
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
21/23J.Ph. Tock
5
182
3
4
7
6
High inner splice
SSS
Highest leakElectrical integrity issueReversed beam screen(s)Beam opticsDS Coll.
Spread all around : work on leaks, PIMs,
SAM (He, DN160)Y-lines repair
CC Consolidation / InspectionDN 200 installationTriplet braid
Cryo-dipole
Circuit and splices issues
Technology Department
Chamonix 2011 LHC Performance Workshop
Conclusions
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
22/23J.Ph. Tock
[FTE] [%]6.4 32% Cryomagnets Exchange4.5 23% DS Collimators4 20% Other planned work
5.1 26% New issues / NC20 TOTAL
The list of interventions on superconducting magnets and circuits (other than main splices consolidation) has been presented.Work is foreseen all along the LHCA team to carry out these interventions in the allocated time has been presented; the ratio of experienced staff (<1/3) seems lowThe assumed baseline does not include the exchange of cryomagnets with a reversed beam screen; adding this would have a major impact (resources, time?)Extra preparatory work is required to gain knowledge on inner splices with high resistanceA value of 30% for new issues & NC seems more realistic
Technology Department
Chamonix 2011 LHC Performance Workshop
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
23/23J.Ph. Tock
Thank you for your attentionAnd to many persons for their infos, slides,
inputs, …
?
Technology Department
Chamonix 2011 LHC Performance Workshop
Spare slides
24th of January 2011
Cryomagnets, Interconnections, Superconducting Circuits:What to do in 2012/13 if you are not consolidating
splices ?
Actions to get data to make an educated decision:Replace “only” magnets that will not withstand the LHC lifetime with
margin
- Detailed modeling of all the dipole inner splices and of the EM forces- Determine correlation between electrical resistance and mechanical strength (model and test on dedicated samples) and see if it is a relevant criterion[Will also define the correlation between cryolab and FRESCA resistance measurements]- Perform extra tests on cold masses (removed from tunnel ?) and/or on representative samples (No of cycles LHC lifetime equivalent) to validate acceptable resistance level (Approach used for the 6 kA pray-hand splices)
Splices test programme
24/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
High internal splices resistances (1/5)LHC machine and spare status
The cryodipole specification is < 7 nOhm for dipolesAll were measured precisely several times (nQPS)
From Zinur Charifoulline
Dipoles: 40 (13A,27B) > 7.5 nOhm 18 (7A, 11B) > 10 nOhm (≈ 5 )3 (1A,2B) > 20 nOhm (> 10
)
Quads: 4(5) are > 10 nOhm1 [Q7R3] is > 20 nOhm
Spare dipole CM: Max: 21A, 23B (44 in total) ≈ 8.1 nOhmTested : 12A, 11B (23 tested) ≈ 9.6 nOhm
24th of January 2011
25/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
High internal splices resistances (2/5)Experience so far
3 cases : 2 from the machine and 1 from the spares stock
Ref: LHC Project Note 430 : Dipole Magnet Splice Resistance from SM18 data
2334:(S12): R ≈ 100 nOhm Interpole splice D1
2303:(S67): R ≈ 50 nOhm Interpole splice D22420:(Spare): R ≈ 25 nOhm Interaperture splice
Pictures from H Prin (MSC-LMF)
Almost no soldering in splices
24th of January 2011
26/23J.Ph. Tock
Technology Department
Chamonix 2011 LHC Performance Workshop
High internal splices resistances (3/5)Degradation : Experience so far
Test report EDMS No1008959 : Splice Resistance measurements in SM18 : 2303
(TE-MSC-TF)
2303:(S67): R ≈ 50 nOhm Interpole splice D2
Extensively tested in SM18 in 2009:-1000 cycles from 50A to 9 kA (5 TeV eq.) @ 50A/s-10 hours @ 9kA-6 provoked quenches @ 9 kA-Thermal cycle to RT-Training up to 11850A-500 cycles from 5kA to 11.85 kA (Nom)-10 hours @ 11.85kA-5 provoked quenches @ 11.85 kA-Training up to 12.85 kA (Ultimate) in 2 natural quenchesNo change of the splice resistance even after
this extensive fatigue test in SM18To be analysed in the LHC machine in
details24th of January 2011
27/23J.Ph. Tock