1. Closing of sector 7/8 Interconnections of LHC cryomagnets
MARIC 22-Nov-2006
PLAN
Sector 7/8 is closed
Production history and lessons learned
Technical history and lessons learned
Conclusions
by F. Seyvet, on behalf of the ARC and LSS interconnection team

2. MARIC – Closing of sector 78 (F. Seyvet)
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MARIC – Closing of sector 78 (F. Seyvet)

3. Leak status after closure of 7/8
Leak detection with 1 bar of He in CM circuit and
the insulation vacuum pumped
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MARIC – Closing of sector 78 (F. Seyvet)

4. MARIC – Closing of sector 78 (F. Seyvet)
Production history
Key milestones
Install 1st magnet (Feb.05)
Start interconnection activities 7/8 (Nov.05)
1st PAQ test (end.Mar.06)
1st in-situ line N insertion (mid.Apr.06)
All dipoles aligned in sector (end.Apr.06)
All SSS aligned (end.Jul.06)
1st vacuum sector closure (end.Jul.06)
1st MPAQ (mid.Aug.06)
1st MHVQN (end.Sep.06)
All DFB aligned (mid.Oct.06)
Closure of LHC sector 7/ (Fri. 10.Nov.2006)
Pressure test this WE:
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MARIC – Closing of sector 78 (F. Seyvet)

5. MARIC – Closing of sector 78 (F. Seyvet)
Production history
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MARIC – Closing of sector 78 (F. Seyvet)

6. Progress reports – history
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MARIC – Closing of sector 78 (F. Seyvet)

7. Progress reports – history
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MARIC – Closing of sector 78 (F. Seyvet)

8. Progress reports – history
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MARIC – Closing of sector 78 (F. Seyvet)

9. Progress reports - history
**QRL partially filled with He
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MARIC – Closing of sector 78 (F. Seyvet)

10. Progress summary: some rates vs. configuration
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MARIC – Closing of sector 78 (F. Seyvet)

11. MARIC – Closing of sector 78 (F. Seyvet)
Production history Coordination of the interconnection activities in DS
Complex sequence of operations:
Connect all main BB and spools (IEG) – STANDARD*
MPAQ (MEL)
Connect last QBQ type interconnect: Solder main BB (IEG)
Connect last QBQ type interconnect: US weld spools (IEG + MCS-ET)
*…Line N insertion (MCS-IC),,in //
Tack weld of N sleeves (IEG)
6kA cabling (MCS-ET)
600A cabling (IEG)
Continuity test (MEL) / to be coordinated with DFB activities
6kA soldering (MCS-ET)
600A soldering (IEG)
Continuity re-test (MEL) / to be coordinated with DFB activities
6kA insulation (MCS-SC)
600 A insulation (IEG)
M.HV test (MEL) / to be coordinated with DFB activities
Us weld 600A line N cable (IEG)
Electrical continuity check (MEL)
*…Weld specific connection for thermal heat exchanger of line N (LSS IEG team+MCS-IC)
Gets STANDARD again
Just before closure, install specific cryogenic instrumentation (ACR)
=>Close follow-up & coordination required to minimise time lags
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MARIC – Closing of sector 78 (F. Seyvet)

12. History: Sector 7/8, a bench test for the sequence of operations
PAQ
MPAQ and MHVQN tests (Aug.’06-Sep’06)
Jumpers and leak tests
Leak test of LD sleeve welds in jumpers (end July’06)
Constraint: Cannot close QBQ type interconnect M lines before jumper welds are validated
Pumping through IFS for CM circuit global leak test (Aug.’06) instead of through LD line in jumper
This frees the closing of all jumpers without waiting for vacuum sector test
Leak detection
Closure of W bellows with MLI and thermal shield in place (Aug.’06)
Addition of the final visual inspection before closure (Sep.06)
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MARIC – Closing of sector 78 (F. Seyvet)

13. Production history – lessons learned
There is a significant drop of productivity in the remaining activities at the end of the closure of a sector
The “turning” point is around 80%, depending on the activities
This can be attributed mainly to:
non-conformities
A set of constraints generating “natural” holes in the chain of activities
Coordination in the DS zones is more complex
=> During the last phase of the interconnection activities in a sector, focus should be put on
Reducing time lags between activities (detailed daily planning)
Reducing the number of holes (reactivity to NC)
Coordination focus for DS zones
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MARIC – Closing of sector 78 (F. Seyvet)

14. Quality history: technical lessons learned
Main BB insulation
Spool insulation(**)
Improvement of TIG welding procedure
Collaret material leaks in the beam tubes (significant – seal developed)
Objects found in the beam tubes (RF tests)
Line N ultrasonic welds (see Davide T.’s talk**)
Main BB soldering (see Davide T.’s talk**)
Leaks detected before closure
Leaks after closure
Status and analysis for CM circuit leaks(**)
Some o-ring used for W closure leaktight have been found deformed: spares joint were used, “new” joints installed
Damaged bellows(**)
A set of PIM (16units, 8inter.) is to be replaced in the DS zones
(**) treated in more details during today’s MARIC presentations
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MARIC – Closing of sector 78 (F. Seyvet)

15. Quality issues – Poor insulation of spools in magnet extremities
ELQA inspection summary (Feb.’06)
-Solution identified (MEL)
-Mountability validated with IEG operators
-Validation in SM18 on cold tests bench for stability when submitted to He flux
-Level of radiation (for 25 years, in ARC interconnects) determined and validated for material (PE)
-Validation by EEWG
QBBi.B13L8
QQBi.12L8
Dipole 1279
Before cold test in SM18
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MARIC – Closing of sector 78 (F. Seyvet)

16. Leak detected after closure - Status
Leak detection with 1 bar of He in CM circuit and
the insulation vacuum pumped to ~10-2 mbar
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MARIC – Closing of sector 78 (F. Seyvet)

17. Leak detected after closure – Quick analysis
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MARIC – Closing of sector 78 (F. Seyvet)

18. Leaks after closure – General observations
We have observed that after W closure of 14 vacuum sector, a leak in the cold mass circuit was detected (1 bar of He) in 7 cases over a total of approximately 1800 welds (ARC+DS: from Q7r7 to Q7L8).
Leak localisation method is efficient
Average number of interconnects that had to be opened for leak detection: 2.1 per leak [set: 2,3,2,1,3,1,3]
A missing weld in line M2 was found in QBBi.B22L8.
Since then, the CERN independent QA team (ICIT) controls systematically 100% of all welds done by IEG
The IEG welds, that were found leaking during global leak test, have ALL been visually inspected by both IEG quality controllers and by CERN independent QA team (ICIT).
They were not detected by visual inspection (ICIT + IEG)
Another solution than the visual inspection is recommended to localise leaks of the order >10-2/10-3 mbar.l.s before W closure (work on-going, cf. Paolo F. and Paul C.)
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MARIC – Closing of sector 78 (F. Seyvet)

19. MARIC – Closing of sector 78 (F. Seyvet)
2 analysis pf leaks: QQBI.29L8 and QBBi.B27L8 Both M3, left side, external lip in the middle of the groove
Courtesy of TS-MME:
« … analyses préliminaires des brides fuyardes.
Présence d'une fissure associée à la présence de Cl, Zn et Cu pour QQBI29L8 (L'origine la plus probable pour la pollution est l'utilisation de l'eau à braser (Chlorure de Zinc) avec du Cu dissout).
Présence de petites fissures ainsi que des trous associés à la présence de Cl, Al, Ca et Si pour QBBIB27L8 (probablement la même origine que précedemment citée) … »
QQBI.29L8 – dipole 2033
QBBi.B27L8 – dipole 1018
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MARIC – Closing of sector 78 (F. Seyvet)

20. Quality issues – Damaged interconnect bellows
Deformation only
10 cases of plug-in-modules or nested bellows deformed (without any material removal)
AND at the same time, 8 cases where wrong PIM have been mounted (SM instead of MM), in the DS zones
QQBI.10L8, PIM, V1
Accetable as they will all “survive” the first cool down (cf. C. Garion)
BUT there is a strong recommendation to organize a test campaign, in order to
quantify effects of deformation
estimate life duration (no. of cool downs & quench) of damaged parts
Develop a repair (if possible)
“Penetration” or Material removal
2 cases of “serious” defects on nested bellows, line V2, in QBBi.10R7 and QQEi.11L8, 1 case of X bellow in QBQi.8L8
Matter removal on the top of one bellow undulation, estimated visually around mm deep (material at this location is 0.15 mm thick)
QBBi.10r7 nested bellow AND line X in QBQi.8L8 were leak-tested by VAC => showed no leak,
QQEi.11L8 could not be tested (no time)
For nested bellows: only known repair, for the moment, requires removal of the cryo-magnet.
For the moment: USE AS IS (planning constraint + acceptability for pressure test and cool dowm)
For X line, replacement is easier
Specific effort required to (1) quantify effect of damage, and (2) develop a repair
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MARIC – Closing of sector 78 (F. Seyvet)

21. MARIC – Closing of sector 78 (F. Seyvet)
Conclusion
Sector 7/8 was a bench test, from which technical and production lessons can be learned
Analysis continues, and should later include
Resources used (rates vs. team size and equipment)
Technical issues encountered by VAC, MEL
Sequence optimisation
Etc.
Sector 7/8 pressure test occurs this week-end AND there is already work to do
In the mean time, let’s celebrate…
Reminder: Tomorrow at 3:00 pm in 927
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MARIC – Closing of sector 78 (F. Seyvet)