cryomagnets, interconnections, superconducting circuits · 2011. 11. 23. · cryomagnets,...
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Technology
Department
Cryomagnets, Interconnections, Superconducting Circuits:
24th of January 2011 Chamonix 2011 LHC Performance Workshop
What to do in 2012/13 if you are not consolidating splices ?
1/23
J.Ph. Tock
Technology
Department
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 Chamonix 2011 LHC Performance Workshop
What to do in 2012/13 if you are not consolidating splices ?
2/23
J.Ph. Tock
Technology
DepartmentContext : The impact of these “special” interventions
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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
3/23
J.Ph. Tock
Technology
DepartmentIn-situ work or cryomagnet replacement? (1/2)
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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)
4/23
J.Ph. Tock
Technology
DepartmentIn-situ work or cryomagnet replacement? (2/2)
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 shift
Workload: About 600 man hours per standard cryodipole replacement
Welders, mechanics, electromechanics, ELQA, QA, leak tester
Less if consecutive magnets
5/23
J.Ph. Tock
Technology
Department
Cryomagnets, Interconnections, Superconducting Circuits:
Vacuum related issues (1/3)
24th of January 2011 Chamonix 2011 LHC Performance Workshop
What to do in 2012/13 if you are not consolidating splices ?
Leaks
Subsector is localized but not the exact leak origin
Time is required before opening & during the shutdown for leak detection/localisation
Present status : about 20 leaks / 11 are important / 1 is critical (A27L4)
Usually, repairable in-situ
New leaks could appear before the next long shutdown or be created by the warm-up
Typical 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 situation
Only one cryomagnet could have potentially to be exchanged (A27L4) 6/23
J.Ph. Tock
Technology
Department
Cryomagnets, Interconnections, Superconducting Circuits:
Vacuum related issues (2/3)
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 extremities
18/32 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-up
Conclusion: 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
7/23
J.Ph. Tock
Technology
Department
Cryomagnets, Interconnections, Superconducting Circuits:
Vacuum related issues (3/3)
24th of January 2011 Chamonix 2011 LHC Performance Workshop
What to do in 2012/13 if you are not consolidating splices ?
Nested bellows:About 55 small damages identified / 2 are heavier
Inspection 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 planned
Beam 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 34
This could be an issue for cryogenics and electron cloud build-up
VSC follows that with ABP & CRG
No 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
8/23
J.Ph. Tock
Technology
DepartmentConsolidation of SAM Helium level gauges
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 hose
It is planned to consolidate the 2 remaining ones
(Q6R2, Q6L8) during the long shutdown
Repair of leaking Y-lines
It is planned to consolidate the 2 known cases
(S78:17-19R7 & S81:19-22R8) during the long
shutdown
9/23
J.Ph. Tock
Technology
DepartmentInstallation of Pressure Relief Devices
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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)
10/23
J.Ph. Tock
Technology
Department
Triplets braid
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 R8
NCR 982513 982506 982524 982518 982511 982525 982512 982517
Action Remove Install Remove Install Install Remove Remove Install
Stat./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 available11/23
J.Ph. Tock
Technology
Department
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 displacement
Addition of extra insulation to go up to ultimate energy
12/23
J.Ph. Tock
Technology
Department
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 Remark
RCO.A81B2 81 Circuit is open
RCBH31.R7B1 78 Circuit is too resistive
RCOSX3.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
13/23
J.Ph. Tock
Technology
Department
24th of January 2011 Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
What to do in 2012/13 if you are not consolidating splices ?
Cryomagnets issues: High internal splice resistanceElectr(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 resistance14/23
J.Ph. Tock
To be disconnected for
DS Coll installation
Technology
Department
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 dipoles
15/23
J.Ph. Tock
Dip ID Sector Issue Status
1007 78 Breakdown at 1.6 kV Diagnostic (IFS) then exchange if not repairable in tunnel
1263 67 IFS wires Inspect then likely repairable in the tunnel
1372 12 IFS wires Inspect then likely repairable in the tunnel
2007 78 QH likely damaged Diagnostic (TDR) then advisable to exchange
2138 45 QH likely damaged Diagnostic (TDR) then advisable to exchange
2214 45 QH likely damaged Diagnostic (TDR) then advisable to exchange
2395 12 IFS wires Inspect then likely repairable in the tunnel
2413 12 Weakness in 3 HF QH Advisable to exchange
3708 23 IFS wires Inspect then likely repairable in the tunnel
Has also a high inner splice resistance
Technology
Department
Cryomagnets, Interconnections, Superconducting Circuits:
Beam optics
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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: Q28,32
Q5L8 : 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)
16/23
J.Ph. Tock
Technology
Department
Cryomagnets, Interconnections, Superconducting Circuits:
DS Collimators (See previous presentation by V Parma)
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 Radially
DFBA to move # 2 Affect also warm region
DS Collimators # 4 TCRYO
New cryostats # 3 1 CC’ of ≈ 9 m length
Jumper longi motion # 4 DFBA & Q7: Not standard
Modif line N # 6 (8)
Involves surface work
17/23
J.Ph. Tock
Technology
Department
Miscellaneous
24th of January 2011 Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
What to do in 2012/13 if you are not consolidating splices ?
BPM cables checks and repairs
RP samples : See ECR LHC-LI-EC-0001 for details
Recover and measure some of them ;
New ones to be installed ?
New issues appearing before long shutdown
Detected during operation (Higher L, E, time…)
Non-conformities generated during the long
shutdown
18/23
J.Ph. Tock
Technology
Department
•How many cryomagnets to exchange? Spares?
24th of January 2011 Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
What to do in 2012/13 if you are not consolidating splices ?
19/23
J.Ph. Tock
MB SSS Tot
1 8 1 9 High inner splice resistance To be confirmed after tests/study
2 5 0 5 Electrical integrity Between 1 and 9
3 0 2 2 Beam optics Restoration of MQS in 34 only
4 1 0 1 Leaks Depending on repairability
5 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
DepartmentThe special interventions team
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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 interfaces
Team leader 1 0 1 On-site
Expert welder 1 1 2 All types of welds
Welder 0 1 1 Assistant
Welders Automatic and manual (including QA,…)
Expert electromechanic 1 0 1 Ultrasonic welds
Electromechanics 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 1.5
ELQA Krakow Collaboration: Not in total
QA 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
The work location
24th of January 2011 Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
What to do in 2012/13 if you are not consolidating splices ?
21/23
J.Ph. Tock
High inner splice
SSS
Highest leak
Electrical integrity issue
Reversed beam screen(s)
Beam opticsDS Coll.
Spread all around : work on leaks, PIMs,
SAM (He, DN160)
Y-lines repairCC Consolidation / InspectionDN 200 installationTriplet braid
Cryo-dipole
Circuit and splices issues
Technology
DepartmentConclusions
24th of January 2011 Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
What to do in 2012/13 if you are not consolidating splices ?
22/23
J.Ph. Tock
[FTE] [%]
6.4 32% Cryomagnets Exchange
4.5 23% DS Collimators
4 20% Other planned work
5.1 26% New issues / NC
20 TOTAL
The list of interventions on superconducting magnets and circuits (other than
main splices consolidation) has been presented.
Work is foreseen all along the LHC
A team to carry out these interventions in the allocated time has been
presented; the ratio of experienced staff (<1/3) seems low
The 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
resistance
A value of 30% for new issues & NC seems more realistic
Technology
Department
24th of January 2011 Chamonix 2011 LHC Performance Workshop
Cryomagnets, Interconnections, Superconducting Circuits:
What to do in 2012/13 if you are not consolidating splices ?
23/23
J.Ph. Tock
Thank you for your attentionAnd to many persons for their infos, slides, inputs, …
Technology
DepartmentSpare slides
24th of January 2011 Chamonix 2011 LHC Performance Workshop
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
24/23
J.Ph. Tock
Technology
Department
High internal splices resistances (1/5)
LHC machine and spare status
The cryodipole specification is < 7 nOhm for dipoles
All 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 nOhm
1 [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 Chamonix 2011 LHC Performance Workshop25/23
J.Ph. Tock
Technology
Department
High internal splices resistances (2/5)
Experience so far3 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 D2
2420:(Spare): R ≈ 25 nOhm Interaperture splice
Pictures from H Prin (MSC-LMF)
Almost no soldering in splices
24th of January 2011 Chamonix 2011 LHC Performance Workshop26/23
J.Ph. Tock
Technology
Department
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 quenches
No change of the splice resistance even after this
extensive fatigue test in SM18
To be analysed in the LHC machine in details
24th of January 2011 Chamonix 2011 LHC Performance Workshop27/23
J.Ph. Tock
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