A. Perin, TE/CRG, DFBA LSC Page 2 LHC Long Shutdown 1 Committee June 14 th, 2013 A. Perin (TE-CRG) On behalf of the DFBA splices consolidation team: S. Atieh (EN-MME), P. Chambouvet (TE-CRG), J.M. Debernard (TE-CRG), O. Pirotte (TE-CRG), A. Lees (TE- CRG), J.-P. Tock (TE-MSC), R. Principe (TE-MSC), F. Savary (TE-MSC), D. Duarte Ramos (TE-MSC), C. Scheuerlein (TE-MSC), S. Heck (TE-MSC), D. Lombard (EN-MME), J.-F. Poncet (EN-MME), M. Bernardini (EN-MEF), K. Foraz (EN-MEF), R. Girardot (TE-CRG), P. Cruikshank (TE-VSC), J. Finelle (TE-VSC), V. Baglin (TE-VSC), S. Triquet (TE-MSC), Giulia Papotti (BE-OP), F. Morell (TE-CRG)

A. Perin, TE/CRG, DFBA LSC Page 3 Outline Feedback from first operations Global Status Current issues and how we cope with them Conclusions

A. Perin, TE/CRG, DFBA LSC Page 4 Main work planned for LS1 on DFBAs Shuffling module High current module SHM-HCM splices CL – busbar splices (6x) Essentially same type as magnet-magnet Variant based on magnet-magnet Lyras (only on right side) CL line

A. Perin, TE/CRG, DFBA LSC Page 5 Summary of splice work in DFBAs for LS1 During LS1 several type of consolidation will be performed on all DFBAs. Non busbar system consolidations will include (mainly): flexible hoses in the jumper and safety disks. Consolidations on the 13 kA superconducting circuits Consolidation of the 13 kA splices:  135 splices  14 "standard" DFBAs, 2 special cases DFBAP and DFBAK Consolidation of the lyras on the right side shuffling modules

A. Perin, TE/CRG, DFBA LSC Page 6 First feedback from initial operations Work organization and sequence ok: thanks to all !!!! Coordination tools (web site, schedulesm dashboards, LMCO, etc.) ok Durations and estimated personnel: globally ok, most critical operations Busbar consolidation Consolidation of CL line can interfere with other operations Special operation on DFBAK proceeds very well (thank to the team!!!) : no need to remove the High Current Module! Unplanned issues: Delay in the delivery of support for vacuum valves: no major impact until know by rescheduling/anticipating mechanical work Problem with busbar preparation (broaching): cf slides, shunt installation operations halted since 24 May (splice task force approved solution being implemented, restart 24 June) Short to ground in HCM-LCM IC (not impact on 13 kA splices)

A. Perin, TE/CRG, DFBA LSC Page 7 Baseline dashboard Tracking global dashboard

A. Perin, TE/CRG, DFBA LSC Page 8 Global status: Up to and including access to splices: on time, access to 24 splices done Shunt installation stopped after consolidation of 12 splices (18 shunts) Also website for daily updates:

A. Perin, TE/CRG, DFBA LSC Page 9 SHM to HCM interconnection Sequence so far as planned Some difficulties due to geometry (manageable) Reached "ready for shunt installation" step.

A. Perin, TE/CRG, DFBA LSC Page 10 Pigtail to busbar interconnections Sequence so far as planned Reached final leak test step. Some difficulties due to geometry (manageable)

A. Perin, TE/CRG, DFBA LSC Page 11 Special SHM-HCM interconnection of DFBAK No transport of HCM Splices fully consolidated Welding being done

A. Perin, TE/CRG, DFBA LSC Page 12 R. Principe, TE-MSC Broaching is used to prepare the busbar side surfaces before brazing the shunts

A. Perin, TE/CRG, DFBA LSC Page 13 R. Principe, TE-MSC

A. Perin, TE/CRG, DFBA LSC Page 14 R. Principe, TE-MSC

A. Perin, TE/CRG, DFBA LSC Page 15 R. Principe, TE-MSC A. Lees, TE-CR Calculations performed Buckling of side walls Stress in solder Support tooling Can explain the observed result used for improving the tooling R. Principe, TE-MSC A. Lees, TE-CR

A. Perin, TE/CRG, DFBA LSC Page 16 R. Principe, TE-MSC Broaching tests with reduced chip thickness (was approximately 250 for failed one)

A. Perin, TE/CRG, DFBA LSC Page 17 R. Principe, TE-MSC A. Lees, TE-CR Measures to be taken

A. Perin, TE/CRG, DFBA LSC Page 18 Analysis & improvements on broaching operation The problem was caused by: Too high force applied for broaching, due to too thick cut and/or geometry of busbars Non full-area support under the U-part Measures to solve the issue Improve the supporting tooling Reduce the thickness of the cut/chip to reduce force (increase the number of steps) Check the geometry Prepare the busbar to fit in acceptable geometry. Validate geometry. Limit the applied force (applied pressure) Improve traceability and process control Measures validated for re-start of work by the Splice Task Force of Work can restart. Date defined by delivery of new tooling: 24 June

A. Perin, TE/CRG, DFBA LSC Page 19 Non conformity in electrical insulation in DFBAK ELQA at cold ok ELQA at room temperature found a degraded insulation in circuit RCSA56B2 (spool mid point). NC EDMS approx. 2-4 kOhms to ground approx. 6.5 m from current voltage tap. No probelem to other circuits. Approximately area of HCM-LCM interconnection determined by ELQA Vtap Identified problem area interconnection

A. Perin, TE/CRG, DFBA LSC Page 20 IC between HCM and LCM: DFBAK RCSA56B2 (spool mid point), env. 2-4 kOhms vers la terre pas vers les autres env. 6.5m depuis le Vtap Cut (d 135) Cut (d157) Cut (d 175)

A. Perin, TE/CRG, DFBA LSC Page 21 Observed damage to the RCSA56B2 busbar Picture G. D'angelo location of damage IC was opened, sleeves cut Origin of problem confirmed by ELQA team Damage to insulation due to contact with metal edge Picture G. D'angelo

A. Perin, TE/CRG, DFBA LSC Page 22 Other observations in the HCM-LCM interconnection Metal edged unprotected contact with busbars. Presence of dust of fiberglass protection.

A. Perin, TE/CRG, DFBA LSC Page 23 Findings DFBAK The short to ground of circuit RCSA56B2 was identified at the HCNM-LCM interconnection of the DFBAK The short was due to a damaged insulation resulting from friction on a metal edge in the interconnection Other issues with the protection of metal edges and busbar insulation were identified in the interconnection. There is a strong potential for damage to the insulation with the existing configuration The insulation will be repaired and the configuration will be improved with insulating pieces at the flanges and towards the interconnection sleeve. Other DFBAs: HCM-LCM interconnections: Configuration essentially identical to the DFBAK according to pictures : same potential risk Can probably be checked by X-ray SHM-HCM interconnections: N' line: ok for all DFBAs N line: ok for 5 / 11 IC. Can probably be checked by X- rays

A. Perin, TE/CRG, DFBA LSC Page 24 Actions & possible consolidation for the HCM-LCM IC Picture F. Laurent SHM-HCM IC of DFBAD Presented at MP3 of 04 June 2013: recommendations (EDMS ) Damage simlar to the observed NC likely to occur at locations A & B. repair time approx 6-8 weeks. Inspect and repair. Less likely in location C. Inspect. Inspect (X-Ray) other potentially risky IC. Action plan : Develop a consolidation solution for the HCM-LCM interconnection (protections, cf pictures). Validation by MP3 ( ) Perform an assessment of the situation for all line N SHM-HCM interconnections for whiche there is no documentation (X-rays). Plan a possible intervention. Estimation of time & resources (preliminary): Duration: 5-6 days / IC mechanics + 2 days for leak tests Possible teams being defined Budget estimation: approx. 90'000 CHF

A. Perin, TE/CRG, DFBA LSC Page 25 Conclusions Work organization and sequence ok: thanks to all !!!! Durations and estimated personnel: globally ok Special operation on DFBAK proceeds very well (thank to the team!!!) : no need to remove the High Current Module! Unplanned issues: Delay in the delivery of support for vacuum valves: no major impact until know by rescheduling/anticipating mechanical work Problem with busbar preparation (broaching): cf slides, shunt installation operations halted since 24 May (splice task force approved solution being implemented, restart 24 June) Short to ground in HCM-LCM IC: evaluation being done for decision asap Global re-scheduling being done: probable impact 1 month delay for initial DFBAs. No impact on global SMACC schedule. Work on lyras will be presented to splice task force on 19 June.

A. Perin, TE/CRG, DFBA LSC Page 27 Project organization (main tasks) Project coordination A. Perin (TE-CRG) Dep.: O.Pirotte (TE-CRG) Std. Mech. work A. Perin (TE-CRG) Welding, DFBAP, DFBAK S.Atieh, D. Lombard. (EN-MME) Insulation vac. P. Cruikshank (TE- VSC) Beam Vacuum J. Finelle (TE-VSC) Busbars & shunt R. Principe (TE- MSC) Shunt QC C. Scheuerlein (TE- MSC) ELQA G. D'Angelo (TE- MPE) SMACC coordination J.-P. Tock (TE-MSC), G. Papotti (BE-OP) LS1 scheduling M. Bernardini (EN-MEF) + Survey: M. Tortrat (BE-ABP) + Consolidation of SHM right side lyras (A. Lees, TE-CRG, F. Morell, TE-CRG) + DFBAK: disconnection/reconnectiion: N. Bourcey (TE-MSC) (not needed !) + DFBAK: Transport DFBAK: C. Bertone (EN-HE-HH) (not needed !) Project scheduling R. Girardot (TE-CRG) Operations coordinator N. Bonetti (TE-CRG) QA & Doc. mgmt. S. Knoops(TE-CRG)

A. Perin, TE/CRG, DFBA LSC Page 28 Workflow for SHM-HCM std. splices consolidation Break vacuum Open / cut vacuum envelope & inner sleeves Remove insulation of busbars QC of splice Ok? no Redo splice Machine busbar QC of shunt OK ? Repair shunt Install insulation and supports Weld sleeve Weld vacuum envelope ELQA QC of weld QC of welds yes OK? no yes no Repair Leak tests OK? no yes Repair OK? no yes Repair repair OK ? no yes Repair OK? no yes Leak & pressure tests with sector Beam vacuum equipmt. TE-SVC-LBV TE-CRG-ME TE-MSC-LMF TE-VSC-EIV QC of machined busbar Ok ? TE-MSC-SCD no yes Install shunts TE-MPE-EE EN-MME Cut Open CC IC bellows Prepare work Re-instlall beam vac equipmt. Finalize work