MSC Technical Meeting 29 August 2013
description
Transcript of MSC Technical Meeting 29 August 2013
MSC Technical Meeting29 August 2013
Overheated splice @ QBBI.A21L6
F. Savary with contributions from N. Dalexandro,H. Prin, C. Scheuerlein, P. Voisin
Overheated splice @ QBBI.A21L6 2
Outline
The facts Proposed work plan
Intervention workflow
Description of the repair procedure
Description of the consolidation procedure
Schedule
Status of tooling
Conclusion
2013-08-29
Overheated splice @ QBBI.A21L6 3
The facts Observations in the tunnel in the end of May 2013 (WISH) NCR launched on June 10th, 2013, M2 Int.: https://
edms.cern.ch/document/1290623 As observed by LMF-QA the disconnected cable has been
severely damaged during installation (5 cut strands on the left side, and possibly signs of overheating on both sides)
The splice is part of a 1.9 K resistance outlier segment
2013-08-29
Overheated splice @ QBBI.A21L6 4
Measurements @ cold
2013-08-29
Rmeas=4.75nΩRmax=2.25nΩ
Courtesy Z. Charifoulline
Overheated splice @ QBBI.A21L6 5
Reminder Subject discussed at the LHC Splices TF
Meeting #68, on 30 July 2013 See ref. EDMS 1304524
2013-08-29
Overheated splice @ QBBI.A21L6 6
Intervention workflow
2013-08-29
NCREDMS 1290623
Extract strands for magnetization measurements
• Unsolder M2 Ext., and the spool cables
• Cut / remove the bellow (Left)
• Cut / remove the flange, and spider clamp (Right)
• Remove insulation as needed• Cut / remove ~ 60mm of
copper to check the cable• Possibly, do radiographic
examination
Cable inspection:• Visual• Magnetization
measurements
Cable ok ?
Repair / redo the splice according to new procedure
• Cut / remove more copper, i.e. additional 60mm (only left side)
• Put in place shunts• Re-weld spool
cables• Put in place
standard insulation
YES
NOIn addition to
standard QC, carry out radiographic
examination
Cable ok ?
YES
NOReplace the magnet(s)
Overheated splice @ QBBI.A21L6 7
LS1 Committee, 13th Meeting, 21 June https://indico.cern.ch/conferenceDisplay.py?confId=257962
2013-08-29
Courtesy C. Scheuerlein
Overheated splice @ QBBI.A21L6 8
The environment & space limits
2013-08-29
Overheated splice @ QBBI.A21L6 9
45 mm
Splice opening & preparation work
2013-08-29
45 mm
30 mm
tbd
120 mm
50 mm60 mm
Overheated splice @ QBBI.A21L6 10
Splice reconstruction
2013-08-29
150 mm + 2 x 60 mm (up to 330 mm, in case left side needs to be extended farther)
Smooth blending and overlap, avoid 2 mm step and sharp edges
Overheated splice @ QBBI.A21L6 11
Cut / remove Cu around the cable
2013-08-29
Overheated splice @ QBBI.A21L6 12
Cut / remove Cu around the cable
2013-08-29
Overheated splice @ QBBI.A21L6 13
Reconstruction
2013-08-29
Overheated splice @ QBBI.A21L6 14
Reminder Force @ rupture, and resistance of a splice, both @
4.3 K, as a function of the overlap Note CERN-ATS-Note-2011-074, EDMS 1159508, by
C. Scheuerlein et al.
2013-08-29
The splice proposed for the overheated
cable is in this range
Courtesy C. Scheuerlein
Overheated splice @ QBBI.A21L6 15
2009 – QBBI.B29R3 – M3 line
2013-08-29
Overheated splice @ QBBI.A21L6 16
Carry out ELQC, apply standard checks R8 standard, and R16 becomes R16+12
Cu machining, and shunt installation procedures are standard (as this is a quad. line, @ bottom only)
Insulation needs to be rebuilt in the 60 mm extensions of the splice (50% overlap, pre-preg, …), then the standard insulation system can be put in place
Consolidation procedure & QC
2013-08-29
Overheated splice @ QBBI.A21L6 17
August September October
W34 W35 W36 W37 W38 W39 W40 W41 W42
Procedure to remove Cu / 60mm xxxxx xxxxx xxx__
Inspection procedure, visual, magnetization measurements … actually nothing to do
xxxxx
Procedure to make special splice, including tests (elqc, radiographs, cuts & macros)
xxxxx xxxxx xxxxx
Preparation work in the tunnel xxxxx
Development of special insulation / spider xxxxx xxxxx
Inspection in the tunnel, and tests on the surface (magnetization measurements, …)
xxxxx
Reconstruction of the splice / QC [if cable ok!] xxxxx
Welding of a new bellow / M-flange / QC xxx__
Cu machining and shunt installation / QC __xxx
US welding of the spool cables / QC xxx__
Insulation / Injection / QC __xxx
2013-08-29
This week
Schedule
Overheated splice @ QBBI.A21L6 18
Status on tooling For preparation
Almost finished Induction loop for unsoldering to be optimized,
utilization of tooling recovered from ACCEL (already utilized for the construction of the Q7)
For reconstruction Soldering molds to be designed and fabricated
For testing ELQC, ok Radiographic examination, should be ok [to be
checked with Jean-Michel Dalin]
2013-08-29
Overheated splice @ QBBI.A21L6 19
To understand it better Understand in what conditions there is
overheating Organize the execution of tests on the
surface Heat up a splice + bb progressively, and check
the effect on the copper parts, and insulation (oxidation, color, …)
This will help on deciding what to do in the other cases Statistics in preparation by Sandrine
2013-08-29
Overheated splice @ QBBI.A21L6 20
Conclusions A repair (special splice) is feasible It allows installing the standard shunts, and the standard insulation
system, but not the standard clamp (spider) on the right side Special tooling is needed for the preparation work (induction), and
for the re-soldering (resistive). However, not a major issue The repair is only possible if the cable is sane in the 60mm on the
right side, and in the 60mm or 120 mm on the left side of the original splice We rely on both top & bottom contacts of the 60 mm splice to get an
“almost” standard splice in terms of overlap If the above conditions are not fulfilled, one (or two) magnet(s)
has(have) to be replaced A special splice is also possible if only one magnet is replaced
The repair procedure allows intervention on any type of IC, QBB, QQB, and QBQ, and on any line (M1, M2, and M3)
2013-08-29
Overheated splice @ QBBI.A21L6 21
To be checked … With magnet coordination, what magnet can
we put in place, in case the cable is excessively degraded?
How many magnets do we have available in case there would be other cases?
Statistics (# of known cases of overheated cables) will be shown at the SMACC Meeting of next week
2013-08-29