Leak Testing QC of Cold Vacuum Systems the story so far………. Paul Cruikshank on behalf of TE-VSC colleagues & AL4030 Consortium (S133) 1 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Leak Testing QC of Cold Vacuum Systems - What? Phase 1 leak test – Prior to splice consolidation (Arcs, LSS, QRL)  Air to insulation vacuum  Helium to insulation vacuum  Helium to beam vacuum Phase 2 leak test – During splice consolidation  intermediate testing of new welds: SIT, DFBA, DN200 – on-going M lines – starting today PIM – not yet started Phase 3 leak test – After splice consolidation  Global leak tests after re-closure, including pressure test 2 Complete Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Leak Test QC Sequence: Leak test executed according to procedure by trained technician, Daily report of executed tests & results prepared by team leaders, Result is checked by staff or COFREND certified contract support, Result recorded and stored on TE-VSC-EIV sharepoint page, Result recorded in WISh (where applicable), If NOK, create NCR in MTF (staff or certified contract support), 3 Paul Cruikshank TE/VSC Leak Testing QA SMACC QA team meeting 11/4/2013

Leak Testing of Cold Vacuum Systems Phase 1 - Why?  Status of vacuum system tightness  Localisation of known leaks  Localisation of any new leaks  Leak repairs in masked time  Early warning of unexpected problems 4 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Leak Testing of Cold Vacuum Systems Phase 1 – Helium to BV leaks 5 Status for LHC arcsS5-6S4-5S6-7S7-8S1-2S8-1S3-4S2-3 He to BV leaks Courtesy J.Finelle Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 1 – Air to IV leaks 0-ring 6 MB vessel at central foot B31L5, A21L8 C16R5, A26L7 B32L8 Foot flange o-ring C22L4 Q6L8 Connector feedthrough Jumper weld/material Q7L2 Q29R2 Q21L3 Q21R3 Q33R7 Status for LHC arcsS5-6S4-5S6-7S7-8S1-2S8-1S3-4S2-3 Air leaks (identified to component) Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

22 ‘known’ He leaks in IV prior to LS1 Highest priorities are:S3-4, A27L4.M, cold mass circuit S4-5 QRL SubS B, line C – repair with TE-CRG Note:- LHC operates with these leaks - the 2 big leaks weren’t present at RT after welding & P.Test  - some known leaks accepted ‘use-as-is’ due to lack of time during installation  - some known leaks weren’t found to component level despite search during installation  7 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Helium leak observations in IV ‘Green’ helium leak – IV pressure is rising…………. ….leak elimination will avoid perturbation to cryo system during temp transients 8 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Helium leak observations in IV ‘Red’ helium leak – IV pressure rise & then limited by turbo pump speed… …leak elimination will reduce heat loads and avoid reliance on turbo pumps for pressure equilibrium 9 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 1 – Helium to cryomagnet IV - Correct test conditions have allowed 4 ‘known’ leaks to be discarded.  air leak near gauge, or Penning gauge error, oil vapour pressure (see later) - 4 newly observed small ‘green’ leaks may be due to correct test conditions/extra scrutiny… internal helium leaks identified in arc subsectors after warm-up – 14 identified to component (for repair).  for 6 leaks not identified to component, further tests to be performed in phase 2. - Triplet 5L – helium leak in FF circuit (inside DFBX) stable since 2009 – propose continue ‘use-as-is’. - NC follow-up in MTF. 10 Status for LHC arcsS5-6S4-5S6-7S7-8S1-2S8-1S3-4S2-3 He to IV leak - ‘known’ (pre LS1 data) He to IV leak - identified to subsector2+1(+1)0+1(+1)2+2(+1)1+0(+0)1+0(+1) (+1) He to IV leak - identified to component2+1(+0)0+0(+0)2+1(+1)1+0(+0)0+0(+1) (+1) Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

LT Phase 1 – internal leak types 11 M weld or collar (x3) M2N flexible (x3) K collector (x4) QBBI.8L7, QQBI.22L7, QBBI.B34L7, QBBI.B21R6 K flexible (x3) QBBI.B26L3, QBQI.9R2, QBEI.11R3 QQS current leads (x1) QBQI.9L2 (Q8) QQBI.13L6 (M3) QQBI.7R5 (M2) QBBI.A29L4(M3) Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013 QBQI.18R5 QBQI.26R7 QBQI.33R3

Phase 1 – Helium to QRL IV LS1 foreseen objectives: - Collaborate with TE-CRG to repair known (observed Dec’ 2010) internal helium leak in S45. - Check helium residuals & air leaks after warm-up of the 72 subsectors: but,large & fast pressure rises seen in IV of 5 QRL subsectors during LS1 warm-up, 6 additional internal helium leaks confirmed (5 not present during 2013 operation), all 7 confirmed on header C at multiply compensator. - QRL analysis/action plan/repair is on-going………………….in shadow of SMACC 12 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 2 - Leak test support for M welds 13 - Dedicated leak testing teams. - Results (to be) documented in WISH - Long clamshell tool has been developed and validated: to test 2 M welds simultaneously, to pump and backfill the 214m He volume at a predefined unwelded M sleeve, to bridge a splice NC (if left unwelded). - Standard clamshells also available (M, SSS diode). - First subsector – 16 interconnects - released for vacuum test yesterday (22/7/2013) Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 2 - Leak test support to SIT 14 - Leak testing team attached to SIT production, - Weekly meeting to review past week, next week, any issues, - Test tooling operational - optimisation is continuous process (VSC & MSC)….. - Results documented on VSC/EIV sharepoint page. Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 2 - Leak test support to DFBA 15 - Leak testing team available for DFBA production, - Test tooling optimisation is continuous process (VSC & CRG)….. - Results documented on DFBA site & VSC/EIV sharepoint page. Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 2 - Leak test support to DN Leak testing on call for DN200 production, - Baseline is to make sample intermediate testing to check process (100% phase 3 test) Start of production (~35 made at S78 start) Change of weld parameters/procedure (~ 8 made), Series (5%) - Results documented in WiSH & VSC/EIV sharepoint page. DN200 weld leak (1 E-1 mbarl/s) Adjacent to QQBI.A29R8 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Phase 2 – oil & MLI observations 17 On-going checks: TE-VSC confirms no abnormal insulation vacuum pressure in affected subsectors TE- CRG confirms no abnormal heat loads in affected subsectors. Oil composition analysis on-going – primary pump oil? Origin of oil? Incident during LHC installation tests, eg mobile pump malfunction? Incident during LHC cold operation eg negative pressure gradient cryostat to fixed pump? MLI debris? May come from fast venting/vacuum break – when ? Connection between oil & MLI debris not (yet) understood. Q26L6 - oil in cryostat Sector 8-1 (A11L1.M & A15L1.M) & 2-3 (A11R2.M), Oil traces at several interconnects, accompagnied with MLI debris Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013

Results so far….. Leak Test summary: Phase 1:He to BV– no problems Air to IV– several NC to solve He to IV cryomagnets – 20 confirmed existing leaks, 14 localised for repair He to IV QRL- 7 confirmed compensator leaks, repair on-going Phase 2: SIT, DFBA, DN200– ok, on-going M welds– just starting…. 18 Paul Cruikshank TE/VSC - Leak Test QC of Cold vacuum Systems - 4 th Splice Review, 23/7/2013