DFBA Consolidation: Description and Organisation

2. Third LHC SpliceReview, November 12-14, 2012 DFBA Consolidation: Description and Organisation A. Perin (TE-CRG), S. Atieh (EN-MME), P. Chambouvet (TE-CRG), O. Pirotte (TE-CRG), J.-P. Tock (TE-MSC), R. Principe (TE-MSC), F. Savary (TE-MSC),C. Scheuerlein (TE-MSC)

3. Outline • Foreword: The status of preparation for the consolidation of the splices in the DFBAs does not allow "production readiness" reviewing • Short reminder of the configurations • Cutting & welding technologies • Busbars & shunts • Quality assurance and traceability • Organization of work and sequence of operations • The special cases: DFBAP and DFBAK • Global status & next steps

4. Project organization (main tasks) + DFBAK: disconnection/reconnectiion: N. Bourcey (TE-MSC) + DFBAK: specialmechanicalwork: EN-MME + DFBAK: Transport DFBAK: C. Bertone + Cont. Cryostat IC opening if needed: N. Bourcey (TE-MSC)

5. The 16 DFBAs of LHC Current leads Current leads 2 dipole (EE) 2 dipole (EE) 2 dipole 4 quad 2 dipole 4 quad 2 dipole (EE) 2 dipole (EE) 2 dipole 4 quad 2 dipole 4 quad 2 dipole (EE) 2 dipole (EE) 2 dipole 4 quad 2 dipole 4 quad 2 dipole (EE) 2 dipole (EE) 2 dipole 4 quad 2 dipole 4 quad

6. 13 kA splices in the DFBAs Shuffling module SHM-HCM splices High currentmodule CL – busbarsplices (6x) • 136 x 13 kA splices • 72 busbar to busbar • 64 busbar to current lead pigtail Cu continuous to pigtail Cu pigtail Cu busbar superconductorbusbar superconductorpigtail

7. List of types of splices and variants "Standard": 14 DFBAs "Special": 2 DFBAs Total: 136 13 kA splices in the DFBAs

8. Cutting & welding: SHM-HCM splices 40 mm • Cutting • Orbital cutting for two diameters: validated (see next slides) • Welding • Main problem: very limited space around the pipes • Development is ongoing: baseline manual welding, but it may require partial orbital welding 600 A splices 13 kA splices 160 mm Verysmall clearance in IP1, 3, 5, 7 (only 150 mm) 6 kA splices Vacuum envelope Thermal shield

9. Cutting and welding of sleeves Outer sleeve cutting test Inner SHM-HCM sleeve cutting test • Special mockups have been produced to validate the technologies • SHM- HCM • Busbar to pigtail Inner BB to pigtail sleeve cutting test

10. Weldingoperations • There are "only" 16 DFBAs and about 200 welds (compared to more than 10'000 welds for the magnet-to-magnet splices), but event one defective can result in significant problems. • Most welds are very similar type to the M-M ones • Welding operations will be based on same basic principles and experience as M-M ones (see presentation of S. Atieh tomorrow) • Small number allows slower techniques. Current status is: • Baseline is manual welding (less demanding in terms of preparation and geometry) • Orbital / semi-automatic welding for inaccessible welds

11. Cutting & welding: status • Cutting • Orbital cutting machines delivered: all • Validated for all cases with some minor adaptation work & fine tuning • Welding • Testing will start in the coming week on mockups.

12. SM-HCM splice DFBAD DFBAE Pics by A. Perin

13. SM-HCM: limited access to the bb Construction of the first “mock-up” of the in order to check the ACCESSIBILITY R. Principe, TE-MSC rosario.principe@cern.ch

14. Standard Cu machining is not feasible No place for the “standard” Cu machining tooling.. New solution is required R. Principe, TE-MSC rosario.principe@cern.ch

15. Pig-tail splice Problem of the “step” in the PT quad connection… R. Principe, TE-MSC

16. To be solved Vs. standard approach (“normal” interconnect splices): • Accessibility for the SM-HCM 6 bb configuration (2 dip + 4 quad); • Step shunt for the pig-tail quad line.  Lateral shunts with a new Cu machining system R. Principe, TE-MSC

17. Lateral shuntson the SM-HCM 6 bb config. R. Principe, TE-MSC

18. Drawings of the lateral shunts("standard shunt" is 15 x 50 x 3) R. Principe, TE-MSC

19. Specific cutting tool for the surfacing of the Cu NB. The screw drive has recently been replacedwith a pneumatic piston R. Principe, TE-MSC

20. Cu surfacing machine Development of a new Cu surfacing machine. Precise and stable, no effort on the busbar splice (apart the machine weight) R. Principe, TE-MSC

21. The working principle R. Principe, TE-MSC rosario.principe@cern.ch

22. Newly developed machine R. Principe, TE-MSC • Advantages: • Robust and stable: no effort on the splice • Easier access from the top • Same system for the busbar pigtail and SM-HCM • Good also with "bad" splices (laterally “opened”) • Test performed with the worst splices available in the workshop. Reminder: the tooling can be used inversed (closing the bb) and an “opened” bb can be mechanically modified before surfacing • Very good control of the cutting thickness

23. Soldering & insulation • Lateral soldering of the shunts: • SnPb excess leakage  protection for cleanness • Manual process (SnPb, Mob39, small number) • New insulation system for the SM-HCM splices • a new solution for the internal support is needed too R. Principe, TE-MSC

24. New configuration must be validated: Test program • 1st phase (10 x SM-HCM and 10 x pig-tail splices probes): • Splice soldering  visually inspected by LMF and El tested by Christian S. • Cu surfacing (ongoing)  visual + El test by Ch. S. to see if the machining degrade the splice quality. • Lateral shunts  El test by Ch. S. visual (peeling) + gamma (?) + metallography (?). • 2nd phase • Mechanical testing • Cycling (equivalent to 20’000 current cycles, planned) R. Principe, TE-MSC

25. Status for the shunts • Accessibility for machining the busbars is very limited. The configuration of the busbar-pigtail splices is different for the magnet-to-manet splices. It is not possible to reuse the machines developed for the magnet-to-magnet splices. • A solution (to be fully validated) has been developed to cope with the specific characteristics of the splice in the DFBAs: • Installation of lateral vertical shunts that would solve most issues concerning the accessibility • Special machining with vertical cutting planes • The newly developed configuration is undergoing a validation based on the development of the magnet-to-magnet splices • Mechanically (surface quality, resi • Electrically (at the moment only room temperature) • New insulation and supports are being developed

26. QC of DFBA splices C. Scheuerlein, TE-MSC • The global splice resistance tests of DFBA splices are similar to the R-8/R-16 tests of the standard main interconnection splices. • The possible NDT of side shunts in DFBAs is under study. • For pigtail splices gamma ray images will be taken systematically in order to verify that the stabiliser tongue is soldered onto the opposing busbar cable. Room temperature resistance (R-5) at different stages of the consolidation process of dipole and quadrupole pigtail splices. NDT trials by resistance mapping on side shunts. 26

27. Quality assurance and traceability • There are "only" 16 DFBAs and 136 splices… • … but the quality of the work and conformity to defined procedures must be at same level as for the other splices • Main points: • A quality assurance plan is being defined • The documentation will be managed centrally at project level • All critical work will follow strictly defined procedures • Essentially manual "paper" + photographic data on the field. Reviewed daily and scanned for storage in central database. Not part of WEB Interface for the Shutdown (WISH) • Each operation will be traced (at least) with checklists for execution of operations and a traveller for each location. • Based on system developed during LHC production + improvements

28. Project organization (main tasks) + DFBAK: disconnection/reconnectiion: N. Bourcey (TE-MSC) + DFBAK: specialmechanicalwork: EN-MME + DFBAK: Transport DFBAK: C. Bertone + Cont. Cryostat IC opening if needed: N. Bourcey (TE-MSC)

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

30. Estimation of durations & scheduling • The detailed sequence of operations and the estimated durations have been confirmed • Estimated time for the consolidation of the splices of a DFBA: 6 weeks (1shift) • Work has started to define the detailed schedule for all interventions • Based on the LS1 global schedule, the resources have been estimated and integrated in the global LS1 organization • For the "special DFBAs": • DFBAP needs 2 additional weeks • DFBAK: needs 8 additional weeks • First analysis shows that he consolidation of the DFBA splices could fit within the specified time window. • Detailed scheduling is ongoing.

31. Special case: the SHM to HCM interconnection of the DFBAP • During production one of the 13 kA busbars was cut (overheated and locally destroyed). • The repair was performed by adding two splices on each side to replace the damaged busbars. • Final splice was done with SnPb • Etat initial • Coupercâbles supra • Enleverstabilisation cuivre • Rallongerles deuxbusbars et la stabilisation Cu. • Situation avant connexion • Réalisation de la connexion HCM SHM

32. Repair operations of DFBAP

33. Using a Cu bypass for the DFBAP. • "Long pigtail" • Cross section of min. 140 mm2 of Cu cable min RRR = 100 (smaller for higher RRR) • Could be inside of cold mass or in "N line like" • Ongoing development • Definition of conductor • connections to both sides • insulation (extrapolation of existing technology) • Mockup built to develop the techniques e.g.: 1x flexible cable: 150 mm2, diam19 mm + insulation 2x flexible cable: 70 mm2, diam13 mm + insulation 19 mm cable Calculations A. verweij TE-MPE

34. Bypassconductor for the DFBAP Mockup of the SHM to invetsigatecabel insertion 3D model showing the possible routing of an externalbypasscable • Evaluation on a mockup showed that the insertion of a cable would be very difficult. • The possible development of a cable + interfaces is considered very complex • Outcome of first investigations: • Routing outside of SHM is preferred • The conductor should be based on know busbar technology • Development is ongoing to define the interface to the existing busbar and the mechanical integration and sequence for assembly Developmt. For the Bypassconductor

35. The SHM to HCM interconnection of the DFBAK DFBAK SHMC-HCM IC module • Presence of beam dump pipe forced to shift the HCM towards the transport zone • A special longer connection was needed, with some degree of flexibility (provided by gimbals & bellows). • Two splices: • One done in the workshop. Not accessible in tunnel • The last SHM-HCM connection was done in the tunnel DFBAK: workshop made splices

36. The SHM to HCM interconnection of the DFBAK

37. Consolidating the DFBAK splices • Consolidation • install shunts on the additional splices • access to the splices (with subsequent re-weld) cannot be performed in situ. • Disconnect HCM: 1 interconnection to SHM + 1 interconnection to LCM + instrum • Transport to working area (tunnel not possible during "train" operations ) • Consolidation • reassemble with newly produced components • reconnect • Where? • Baseline: UX65 (cavern at IP 6, approx. 200 m transport) • Estimated duration: 8-10 weeks • Under study: possibility to do it in-situ, without disconnecting the HCM

38. Global status "Standard" DFBAs splices Cutting: all machines delivered. Validation done for 2 types out of 3. Welding: ongoing work on mockups Installation of shunts: new configuration developed. It is being validated. Quality control is in progress. Based on magnet-to-magnet splices experience Special cases DFBAP: preferred solution is a Cu bypass cable. Can be done without moving the DFBAP. Butt requires specific designand development for the interfaces to the busbars. DFBAK: baseline: disconnect the DFBAK HCM (lots of work, but not much development needed). In situ consolidation is under study. Project organization The main sequence of operations and the durations have been defined, resources planned and a detailed schedule is in work Quality assurance: writing of procedures and definition of documentation has just started No critical issue identified Critical, technically and/or in term of schedule

39. Conclusion and nextsteps A lot of work was performed on many aspects, but significant development work is still required with the main areas being • Definition and validation of the welding technlogies • Validation of the new configuration for the shunts • Design and validation of the Cu bypass for the DFBAP • Quality assurance

40. Cutting a splice with defects rosario.principe@cern.ch