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

Leak Testing QC of Cold Vacuum Systems

the story so far……….

Paul Cruikshank on behalf of TE-VSC colleagues & AL4030 Consortium (S133)

1Paul 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-goingM lines – starting todayPIM – 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),

3Paul 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


Leak Testing of Cold Vacuum Systems Phase 1 – Helium to BV leaks

5

Status for LHC arcs S5-6 S4-5 S6-7 S7-8 S1-2 S8-1 S3-4 S2-3

He to BV leaks 0 0 0 0 0 0 0 0

Courtesy J.Finelle


Phase 1 – Air to IV leaks

0-ring

6

MB vessel at central footB31L5, A21L8C16R5, A26L7

B32L8

Foot flange o-ringC22L4Q6L8

Connectorfeedthrough

Jumperweld/material

Q7L2Q29R2Q21L3Q21R3Q33R7


Air leaks (identified to component) 4 5 4 4 8 5 3 6


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

Status of LHC insulation vacuum - helium leaks January 2012

Internal helium leak - with turbo on, equilibrium pressure at 1.9K > 1 e-6 mbar

Internal helium leak - with turbo on, vacuum pressure fluctuations during temp transients

Sector

8-1 A1R A4R A5R A6R A7R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A7L A4L A1L

7-8 A6R A7R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A6L A5L A4L A1L

6-7 A4R A5R A8R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A7L A6L

5-6 A1R A4R A7R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A8L A5L A4L

4-5 A.ACS5R B.ACS5R A5R B5R A6R A7R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A7L A6L A5L A4L A1L

3-4 DSLC.A34 A6R A7R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A7L A6L B5L A5L B.ACS5L A.ACS5L

2-3 A1R A4R A5R A6R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A7L A6L

1-2 A1R A4R A7R A11R A15R A19R A23R A27R A31R A31L A27L A23L A19L A15L A11L A6L A5L A4L A1L

QRL: internal helium leak in S45 subsector B

VACSEC.xxxxx.M


Helium leak observations in IV

‘Green’ helium leak – IV pressure is rising………….

….leak elimination will avoid perturbation to cryo system during temp transients


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


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….

- 20 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


He to IV leak - ‘known’ (pre LS1 data) 3+1 0+1 2+2 2+0 2+0 1+0 2+1 0+3

He to IV leak - identified to subsector 2+1(+1) 0+1(+1) 2+2(+1) 1+0(+0) 1+0(+1) 1+0 2+1 0+1(+1)

He to IV leak - identified to component 2+1(+0) 0+0(+0) 2+1(+1) 1+0(+0) 0+0(+1) 0+0 2+1 0+1(+1)


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)


QBQI.18R5QBQI.26R7QBQI.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


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)


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.


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.


Phase 2 - Leak test support to DN200

16

- 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


Phase 2 – oil & MLI observations

17

On-going checks:TE-VSC confirms no abnormal insulation vacuum pressure in affected subsectorsTE- 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 cryostatSector 8-1 (A11L1.M & A15L1.M) & 2-3 (A11R2.M),Oil traces at several interconnects, accompagnied with MLI debris


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….


Documents

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