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

MARIC – Closing of sector 78 (F. Seyvet) 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Leak status after closure of 7/8 Leak detection with 1 bar of He in CM circuit and the insulation vacuum pumped 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 7/8 (Fri. 10.Nov.2006) Pressure test this WE: 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

MARIC – Closing of sector 78 (F. Seyvet) Production history 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Progress reports – history 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Progress reports – history 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Progress reports – history 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Progress reports - history **QRL partially filled with He 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Progress summary: some rates vs. configuration 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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) 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Leak detected after closure - Status Leak detection with 1 bar of He in CM circuit and the insulation vacuum pumped to ~10-2 mbar 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

Leak detected after closure – Quick analysis 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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.) 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 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 Specific effort required to (1) quantify effect of damage, and (2) develop a repair 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)

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 29/12/2018 07:37 MARIC – Closing of sector 78 (F. Seyvet)