O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 2 4 th LHC Splice Review, July 22-24, 2013 O. Pirotte (TE-CRG), A. Perin (TE-CRG) With contributions from: S. Atieh (EN-MME), P. Chambouvet (TE-CRG), J.M. Debernard (TE-CRG), A. Lees (TE-CRG), J.-P. Tock (TE-MSC), R. Principe (TE-MSC), F. Savary (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),W. Maan (TE-VSC), J. Finelle (TE-VSC), V. Baglin (TE-VSC)

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 3 Outline Introduction Status of the project Feedback from the field Conclusions

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 4 DFBA Splices consolidation planned for LS1 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)

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 5 Consolidation the 13 kA splices of the DFBAs for LS1 135 splices need to be consolidated for improvement of the continuity of the copper stabilizer. They are essentially similar to the magnet-magnet ones. The 13kA splices in the DFBAs shall provide the same functionality as the magnet-magnet ones (avoid leaving "fuses" in the system).

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 6 The 135 splices to consolidate in the DFBAs TypeNumberLocationConfiguration SHM to HCM 64 splices 16 sleeves Pigtail to busbar 64 splices 64 sleeves SHM to HCM DFBAP 1 splice SHM to HCM DFBAK 6 splices "Special": 2 DFBAs "Standard": 14 DFBAs

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 7 Global status of work Website: CERN.CH/LS1-DFBA-CONSOLIDATION (or pass through Work started on 6 DFBAs: DFBAK, DFBAJ, DFBAL, DFBAM, DFBAN, DFBAP Special DFBAs: DFBAK: Special consolidation finished in situ ahead of schedule 1st of July ! No disconnection / transport needed ! Back to standard consolidation DFBAP: access to extra splice is done ahead of schedule ! Installation of shunt pending Lyras: first clamp installed without making holes in SHM. Tuning needed. Main issues on planned operations Problem with broaching: 5 weeks delay (see slides)! Unplanned consolidation: Improvement of insulation in HCM-LCM IC following discovery of short to ground in DFBAK 600A busbar.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 8 Step reached in workflow for SHM-HCM std. splices consolidation 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 Remove 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 Re-instlall beam vac equipmt. Finalize work Done at least once in tunnel NB. All steps completed for special IC in DFBAK X-ray of splices Control of geometry

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 9 Done at least once in tunnel Workflow for pigtail-BB splices consolidation Break vacuum Open door & cut 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 sleeves Close HCM door ELQA QC of welds yes OK? no yes no Repair Leak tests OK? no yes Repair OK? no yes Repair repair OK ? no yes Leak & pressure tests with sector 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 Prepare work X-ray of splices Done at least once in tunnel Install support and MLI

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 10 SHM to HCM interconnection Sequence so far as planned Some difficulties due to geometry (manageable) Reached shunt installed step.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 11 Pigtail to busbar interconnections Sequence so far as planned Leak test performed.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 12 Special SHM-HCM interconnection of DFBAK No transport of HCM Splices fully consolidated Welding + leak tests done: back to standard consolidation

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 13 Special splice of DFBAP SHM-HCM IC opened Access to extra splice done Shunt installation pending Extra splice

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 14 Schedule / dashboards / forecast: main steps Sequence validated Progress as planned. Some difficulties due to non nominal geometry in the SHM-HCM diam. 500 sleeves Durations as planned Major problem with broaching on 24 May. Restarted broaching in tunnel on 5 th July Team is being reinforced to improve speed (not yet taken into account in forecast). Possible improvement by focusing core team on most critical tasks + additional resource on less critical tasks. Approx. 5 weeks Cutting the sleeves Broaching & shunts

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 15 Global schedule overview with forecast Approx. 5 weeks Impact of broaching problem is approx. 5 weeks schedule shift The baseline margin (approx. 5 weeks) has been used up. Consolidation is "just in time" for LS1 planning (not necessarily for SMACC train). Shunts team is being reinforced with objective of "catching up" by November-December 2013.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 16 Feedback from 3 months of operations (1 / 3) Coordination: Organization and tools performed exceeding expectations. Web site very useful with daily updates. No time lost due to coordination issues. Excellent reactivity, precise and timely communication of information. General working conditions: Training on mockups proved very useful Special attention paid to working conditions (example lighting) Time planned for interventions proven adequate (also thanks to mockup training). No extra pressure on field personnel. QA and documentation: Special effort made for measurement and documentation of DFBA. Production and QC documents centralized in one server. Special emphasis on photographic documentation. Centralized: more than 2'000 photographs taken and sorted. Improved lighting for work by special projectors projectors

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 17 Feedback from 3 months of operations (2 / 3) Cutting operations: All tooling performing as planned. Training of personnel adequate. The geometry of the DN500 sleeve of the SHM-HCM interconnection is not always nominal. More manual operations, but can be absorbed by planned durations. No modification of QC steps. Broaching, brazing and insulation of busbars: Broaching: major problem in the broaching operation appeared on 24 May (see next slides) Brazing of shunts according to planned procedures. Repair of two splices done with planned procedure. No problem. No margin on resources. Team being reinforced with two additional persons. Welding (see also presentation by S. Atieh): Special welds performed on DFBAK. All ok. Only 6 "standard" PB welds performed. As planned. No weld in SHM-HCM IC performed yet. These are the most difficult.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 18 Feedback from 3 months of operations (3 / 3) Beam vacuum equipment demounting : Technology of local support works very well. Some shift of activities caused by 3 weeks delay in deliver of special supports (absorbed now). Welding QC (see presentation by J.-M. Dalin) : 6 welds tested. Leak tests (see presentation by P. Cruikshank) : Special welds leak checked on DFBAK. All ok. Only 6 "standard" PB welds performed. As planned. Procedures & tooling ok. Splices QC (see presentation by C. Scheuerlein) : 28 splices tested before consolidation. All ok electrically, 1 not ok with geometry (decision pending). 18 splices tested after consolidation. All ok.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 19 Problem in broaching operation On 24 May 2 splices where damaged on the DFBAK SHM-HCM IC during the broaching operation. Heavy plastic deformation of the U-piece of the splice occurred. Damaged splices Damaged splices following broaching on DFBAK Imprinted marks of tooling

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 20 R. Principe, TE-MSC Broaching is used to prepare the busbar side surfaces before brazing the shunts

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 21 A. Lees, TE-CRG Calculations performed to help determine cause of problem Buckling of side walls Stress in solder Support tooling Can explain the observed result used for improving the tooling A. Lees, TE-CRG

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 22 Test to collapse Tests to collapse requested by the splice task force: Conditions Cutter 19.8 mm without preparation of the bb Splice poor in SnAg (less than 50%) Result To collapse max pressure = 268 and 319 bars (corresponding to kN) Chip thickness (average value) 268 bars: 0.06 and 0.74 mm 319 bars: 0.2 and 0.48 mm 268 bars 319 bars R. Principe, TE- MSC

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 23 R. Principe, TE- MSC Corrective measures to restart work June 24, TE-MSC-LMF got the authorization to restart broaching, with the following recommendations by the task force: Use a new cutter set for each DFBA Use a new support for the cutter basis Suggest chip thickness nominal = 0.05 mm Add 2 cutting steps : 20 mm and 19.9 mm “Remise a zero” of the bb… Prepare the busbar and adjust the cutting tool position before cutting Add a pressure limitation during cutting. I.e. 150 bar valve, tbc.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 24 R. Principe, TE- MSC Illustration of corrective measures Broach modified Digital manometer during broaching (max pressure recorded). Pressure limitation (150 bars). Set of new knives ready Hydraulic pump also available A datalogger has also been ordered.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 25 Summary on broaching operation problem 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 restarted on 5 th July. Successful broaching of 6 splices (12 broaching ops) Completed on 8 th July.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 26 A short to ground was found in a 600 A busbar in the HCM-LCM interconnection in the DFBAK (unrelated to other splice consolidation activities) The short was caused by the contact of the busbar with unprotected sharp edge of a flange. Inspection showed also other similar problems in the interconnection with a high risk of failure un the future. The problem is present in 12 DFBAs. A consolidation solution has been defined and validated. The decision was taken to consolidate all 12 interconnections. Action plan defined. Project launched. Estimation: weeks work to consolidate all. Unplanned consolidation: HCM-LCM interconnections PEEK protection (2 halves) PEEK protection (optional, 2 halves) G11 foil protection Spacer to avoid overheating (concept)

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 27 Busbar lyras in the shuffling module: coupled non-linear Electromagnetic / Structural Analysis with & without clamps Busbar max current before LS1 (11'170 A) Busbar Max UX (mm)  UX (mm) QD QD QF QF213.1 RB RB A. Lees, TE-CRG Busbar Max UX (mm)  UX (mm) QD QD21.4 QF1 1.6 QF20.6 RB RB2-0.5 Busbar 13'000 A with clamps clamps Forces on clamps ClampForce QD440 N QF380 N RB2300 N

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 28 Development of the clamps Access by cutting holes was discounted during the DFBA Splice Review due to the risk of deforming the beam tubes during welding operations. Therefore it was proposed to insert the clamps through the M1, M2, M3 and temperature sensor entrances to the shuffling box. ‘Fly-by-Wire’ technique was proposed to locate clamps was demonstrated on realistic mockup. Design must adapt to large tolerances in position and dimension of busbars. Geometrical constraint to install through M lines and thermometer line, radiation, fatigue, etc. Semi-rigid design with Kevlar cords and Ultem rigid pieces, closed and tightened by a screw system. Extensive prototyping and fatigue tests performed (up to 200'000 cycles at 4x expected load, 77 K) Spec. and design validated by the LHC splice task force. Clamp for RB busbars Clamp for QD & QF busbars

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 29 Training, first installation & installation plans A realistic mockup of the SHM was built. Development and training in realistic conditions. Observation in the DFBAJ and DFBAL show no damage to the busbars, lateral displacements as calculated. Also seen in DFBAJ unexpected longitudinal position of RB busbars (probably since installation). All tooling and methods developed successfully for installation without drilling holes in the SHM. Special tooling required to move busbars and position clamp in unexpected longitudinal RB busbar position. First installation performed on DFBAJ (Sect 5-6) on 2 July (RB). Procedures for remote installation validated but not 100% satisfactory as lateral busbar position (narrow gap) did not allow perfect positioning. To be redone at end of July. Duration as expected about 1/2 day to install clamp. Next steps: install QF/QF clamps on DFBAL beginning of August. Then next DFBAs. Mockup used for training and development RB busbars in DFBAJ showing non nominal position First clamp installed on RB busbars in DFBAJ 02/07/2013

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 30 Conclusions Work organization and sequence ok: thanks to all !!!! Durations and estimated personnel: ok Special operation on DFBAK finished, starting well on DFBAP. Problem with busbar preparation (broaching): shunt installation operations halted from 24 May to 5 July. Technical solution validated. Operations have restarted. Short to ground in HCM-LCM IC, consolidation launched Installation of clamp for lyras in shuffling module without drilling holes successfully developed. First clamp installed. Some tuning needed. Schedule: 5 weeks shift initial DFBAs. No impact on global SMACC schedule but becoming just in time. Resources added to support busbar team.

O. Pirotte, A.Perin, TE/CRG, 4 th LHC Splice Review, Page 31 Let's continue!