August 16 th , 2013 LS1 Committee (LSC) L. Tavian on behalf of A. - - PowerPoint PPT Presentation

• L. Tavian, TE/CRG, LSC 16.08.2013

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August 16th, 2013 LS1 Committee (LSC)

• L. Tavian on behalf of A. Perin & K. Brodzinski, TE-CRG

• L. Tavian, TE/CRG, LSC 16.08.2013

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Content

• Introduction:
• the faulty equipment (QRL & DFBA)
• The failure mode of compensators based on multi-

ply bellows.

• Status and repair plan of QRL compensators
• Status and repair plan of DFBA gimbal bellows
• Conclusions

• L. Tavian, TE/CRG, LSC 16.08.2013

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The faulty equipment (QRL Line C)

Witzenmann DN100 multi-ply bellows compensators (4 plies of 0.3 mm) Internal ply damage (S45, 14R4) External ply damage (S78, 10R7)

• L. Tavian, TE/CRG, LSC 16.08.2013

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The faulty equipment (DFBA)

Calorstat DN120 multi-ply gimbal bellows (2 plies of 0.2 mm) DFBAK shuffling module: Internal ply collapsing

• L. Tavian, TE/CRG, LSC 16.08.2013

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The failure mode (QRL as typical)

Filling of the inter-ply space with time (3-4 years of operation) Pressure increase of the inter-ply space during warm-up  compensator collapsing ! Maxi pressure with conservative assumption: isochoric transformation and space initially at line conditions (P, T)

• CM: 1500 bar
• Line C: 1200 bar
• Line E & F: 120 bar
• Line D: 20 bar
• Line B: 1 bar

He (P, T) Difficult to survive !! Could be saved by non-isochoric process ! A “virtual” leak (not seen during global leak test)

Metallographic observations (EN-MME)

crack

• L. Tavian, TE/CRG, LSC 16.08.2013

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What are the operation indicators ?

Case 1: Ply scratches on the vacuum side: Case 2: Only plastic deformations or ply scratches on the He side:

• No operation indicator !
• But the mechanical integrity of the concerned

compensators is not acceptable  high risk of damage during the next pressure test or cool-down

• Possible identification via:
• Visual inspection (direct or endoscopic)
• 1 case identified on the DFBA (at present)
• Or systematic X-Ray campaigns
• 1 case identified on the QRL (at present)
• Transitory vacuum break
• Followed by permanent He leak (the

virtual leak is becoming a real one) The “easiest” case:

• 6 clear cases identified on the QRL
• 1 case on the QRL with only the He

leak (no transitory vacuum break).

0.2 0.4 0.6 0.8 1 11/4/13 12:00 12/4/13 0:00 QRL vacuum [mbar]

Sector 81 Sub-sector D

• L. Tavian, TE/CRG, LSC 16.08.2013

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Content

• Introduction:
• the faulty equipment (QRL & DFBA)
• The failure mode of compensators based on multi-

ply bellows.

• Status and repair plan of QRL compensators
• Status and repair plan of DFBA gimbal bellows
• Conclusions

• L. Tavian, TE/CRG, LSC 16.08.2013

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QRL Line C compensator status

A B C D E F G H I LT X-ray LT X-ray LT X-ray LT LT LT X-ray LT X-ray LT X-ray Case 1: Damage compensateur identified by LT and confirmed by X-rays : Total (final) 7/560 (1.25 %) Case 2: Damage compensateur (still tight) identified by X-rays only: Total (provisional) 1/115 (~1 %) Leak-tested sub-sector (VSC) X-rayed sub-sector compensators on Line C (CRG, MME) X-rayed sub-sector compensators on Line B, D, F (CRG, MME) X-ray still to be done (according to LSC #14 action) S67 S78 S81 QRL sub-sector S12 S23 S34 S45 S56 X-ray X-ray E E E E E E E E: Extracted from the QRL (Nominal rate: 1 per week)

• L. Tavian, TE/CRG, LSC 16.08.2013

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QRL spare status

• At CERN
• 4 DN100 spare compensators (nominal for line C)
• 8 DN80 spare compensators (could be used in sub-sector E, F, G, H and I where

the flow is reduced)

• The 12 spares are under validation: leak tests to identify possible virtual leaks

(“booming” test) after 10 mechanical cycles.

• Additional spares.
• Meeting with Witzenmann on 6 Aug’13 ( optional contact with BOA and Skodock)
• 5 new spares (DN100): delivery scheduled on CW44 or 45
• New welding procedure more reliable with systematic “booming” test (at CERN)

4 plies 2 rings

Present procedure

Flange 4 plies

New procedure

Flange 4 plies 2 rings

• L. Tavian, TE/CRG, LSC 16.08.2013

Page 11 Page 11 CW 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 1 2 3 4 5 X-Ray S45 & S56 (CRG & MME) X-Ray of remaining QRL (~5.5 sectors) TBC (CRG & MME) CERN spare validation (12 units) (CRG & VSC) Delivery of new spares (5-10 units) New spare validation (5 units) (CRG & VSC) Compensator 1 T1 T2 T1 T2 T3 Compensator 2 T1 T2 T1 T2 T3 Compensator 3 T1 T2 T1 T2 T3 Compensator 4 T1 T2 T1 T2 T3 Compensator 5 T1 T2 T1 T2 T3 Compensator 6 T1 T2 T1 T2 T3 Compensator 7 T1 T2 T1 T2 T3 Compensator 8 T1 T2 T1 T2 T3 T1 Mechanical preparation (CRG) T2 Compensateur integration/welding and leak test (CRG & VSC) T1 Screen and MLI interconnect integration (CRG) T2 External envelop closure/welding (CRG) T3 Individual and global leak test (VSC) T1 (Team 1): 2 persons (2 technicians) T2 (Team 2): 2 persons (1 welder + 1 mechnanics) (TE-VSC support to be added) T3 (Team 3): VSC support 2014 2013 Aug Sep Oct Nov Dec Jan

Repair plan for QRL compensators

Final order and slot allocation to be refined and validated in collaboration with the central coordination (EN-MEF)

• L. Tavian, TE/CRG, LSC 16.08.2013

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Content

• Introduction:
• the faulty equipment (QRL & DFBA)
• The failure mode of compensators based on multi-

ply bellows.

• Status and repair plan of QRL compensators
• Status and repair plan of DFBA gimbal bellows
• Conclusions

• L. Tavian, TE/CRG, LSC 16.08.2013

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DFBA IP Découpe M Inspection

Lower Upper

Découpe M Inspection

Lower upper

DFBAB 1R 07-Aug 08-Aug

• k
• k

1-2 DFBAC 2L 19-Aug DFBAD 2R 13-Aug 14-Aug

• k
• k

2-3 DFBAE 3L 19-Aug DFBAF 3R 21-Aug 3-4 DFBAG 4L 26-Aug DFBAH 4R 28-Aug 4-5 DFBAI 5L 31-Aug DFBAJ 5R 20-Apr 18-Jul

• k
• k

5-6 DFBAK 6L 18-Jul

• k

damaged DFBAL 6R 25-Apr 18-Jul

• k
• k

6-7 DFBAM 7L

• 26-Jul
• k
• k

DFBAN 7R 15-Jun 02-Aug

• k
• k

7-8 DFBAO 8L

• 02-Aug
• k
• k

DFBAP 8R

• 25-Jul
• k
• k

8-1 DFBAA 1L 07-Aug 08-Aug

• k
• k

Dates Bellows status Bellows status Secteur DFBA IP Dates

DFBA gimbal bellows status

Present statistics (total 32 bellows): 1/20 (5 %) Spare status: 2 spare bellows at CERN (still under search) Meeting with Calorstat foreseen end of Aug’13

Endoscopic inspection through line M interconnects Thanks to MSC for early opening

• f M sleeves !

• L. Tavian, TE/CRG, LSC 16.08.2013

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Repair plan for the DFBA gimbal

• Repair work could be eased if bellows can be replaced by rigid assembly

(bus-bars could remain in place)  thermo-mechanical analysis under progress (conclusion by end Aug’13)

• Scenario 1: In-situ repair
• Very tricky access issue
• Very risky operation
• No repair time defined yet
• Scenario 2: Workshop repair
• Mechanical and electrical (112 splices from 13 kA to 600 A) disconnection of the

shuffling module  ~2-3 weeks (MSC, MME, CRG, HE)

• Transport to surface (HE)
• Repair  ~3 weeks (rigid assembly) to ~6 weeks (new gimbal bellows) (MME)
• Transport to tunnel (HE)
• Reconnection of the shuffling module  4 weeks (MSC, MME, CRG, MPE, VSC,

ABP-SU)

• Total : 9 to 13 weeks (2 to 3 months)  Resource availability to be confirmed !

upper bellows Lower bellows

• L. Tavian, TE/CRG, LSC 16.08.2013

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Conclusion

• QRL compensators:
• 8 damaged compensators identified at present on line C including 1 deformed and

tight (identified only via X-ray).

• Line C X-ray on the remaining sub-sectors (+150 kCHF) is highly recommended to

identify all the cases 2  impact if a leak appears at 80 K during next cool-down: 200 kCHF of LN2 + 3 months of delay for the concerned sector.

• The known case repair could be completed by end 2013  to be validated by the

central coordination.

• Additional mechanical analysis is underway to evaluate the failure risk of Line B, D,

E and F compensators (C. Garion).

• DFBA gimbal bellows:
• 1 damaged gimbal bellows identified at present by endoscopic inspection. Inspection

completion by end of Aug’13

• No solution yet for in-situ repair.
• Workshop repair: first rough estimation of 2 to 3 months per shuffling module

depending on repair type (rigid or not)  resource and schedule still to be consolidated.

• Quid of all the other multi-ply bellows operated under cryogenic conditions

(especially under LHe I, LHe II, SHe @ 4.5 K)?

• Under investigation for the DSLs

• L. Tavian, TE/CRG, LSC 16.08.2013

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Acknowledgments

Many thanks to all the Groups which have collaborated to the treatment of this new issue: (By appearance order)

• EN-MME (X-Ray; metallographic analysis,

DFBA repair investigation)

• TE-VSC (global and individual leak tests;

mechanical calculation on bellows)

• EN-MEF (central coordination and schedule)
• TE-MSC (opening of line M sleeves)