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Closing of sector 7/8 Interconnections of LHC cryomagnets

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. Leak status after closure of 7/8.

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Closing of sector 7/8 Interconnections of LHC cryomagnets

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  1. Closing of sector 7/8Interconnections 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)

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

  4. 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 7/8 (Fri. 10.Nov.2006) • Pressure test this WE: MARIC – Closing of sector 78 (F. Seyvet)

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

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

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

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

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

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

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

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

  19. 2 analysis pf leaks: QQBI.29L8 and QBBi.B27L8Both 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 MARIC – Closing of sector 78 (F. Seyvet)

  20. Quality issues – Damaged interconnect bellows Deformation only • 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 0.05-0.1 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 • 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 Specific effort required to (1) quantify effect of damage, and (2) develop a repair MARIC – Closing of sector 78 (F. Seyvet)

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

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