LHC CryogenicsStatus and Perspectives
Serge Claudet, on behalf of the LHC Cryogenics group
LHC - MAC22 05 Dec 2007
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Content• Introduction• Main facts from sector 7-8 (January to July
2007)• Last projects towards completion• Identified weak points (@MAC21) and status• Cryo HWC activities since Mid 2007• Action plans• Summary
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC Sector 4-5 scheme
4.5 K1.9 K
3.3 km4’700 t @ 1.9K≈ 10t/15tHe
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Content• Introduction• Main facts from sector 7-8 (January to July
2007)• Last projects towards completion• Identified weak points (@MAC21) and status• Cryo HWC activities since Mid 2007• Action plans• Summary
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC sector 7-8 - First cool-down
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Availability for HWC: From 7-8 to others
DFBMs
Cryo Maintain LSS: 85% (Since 1st May)
DFBAs
Cryo Maintain ARC: 66% (Since 1st June)
Target LSS: 90%(incl. time lost for quench recovery)
Target ARC: 80%(incl. time lost for quench recovery)
+ Cryogenic tuning to be minimised ?!?
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Heat inleaks
• Average distributed heat inleak at 1.9 K: 0.2 W/m– 20 % of cells operating with degraded insulation vacuum
• Average distributed heat inleak of cells with good vacuum: 0.14 W/m– 33 % below the design estimation
• Average global thermal shield heat inleak: 6.6 W/m– 15 % below the design estimation
0
0.5
1
1.5
2
2.5
3
0 20 40time [h]
[K],
[kP
a],
[MP
a]
0
10
20
30
40
50
60
[g/s
]
Average temperature at HX outlet[K]Pressure at HX outlet [MPa]
Saturated helium pressure [kPa]
Pumping mass-flow [g/s]
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC Cryogenics: duration of cool-down phasesDesignLHC 7-8Final
9 d21 d
3 d14 d
1 d14 d
1 d21 d
80 K
20 K
4.5 K
1.9 K
Total
DesignLHC 7-8Final
DesignLHC 7-8Final
DesignLHC 7-8Final
DesignLHC 7-8Final
14 d / 2 wks70 d / 10 wksELQA
14 d
4 d
3 d
7 d
28 d / 4 wks
Excluding ELQA or extra-works :
Sketches intended to illustrate achievements and medium term expectations
S. Claudet - Jul’07
Proposed for schedule: 8wks-6wks-4wks
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Content• Introduction• Main facts from sector 7-8 (January to July
2007)• Last projects towards completion• Identified weak points (@MAC21) and status• Cryo HWC activities since Mid 2007• Action plans• Summary
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Superconducting links (DSL)Few hundred meters link between DFBL’s and stand-alone magnets
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Problems with leaks at the factory-made welds on belows
Many non conformities from contractor, repaired by CERN
=> Impact on sector 3-4
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Global pressure test of magnets and cryolines
Sector 7-8, 25 Nov 2006
Six sectors May’07 to Nov’07
Remaining 1 sector in Dec’07
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Content• Introduction• Main facts from sector 7-8 (January to July
2007)• Last projects towards completion• Identified weak points (@MAC21) and status• Cryo HWC activities since Mid 2007• Action plans• Summary
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
On-going actions & plans @ MAC21• LN2 logistics to be continued; turbine and flow controls to be
improved for 20 K phase
• Heat loads to be further checked and analysed
• JT valves to be checked and replaced (8x27)
• LHe level / anti-condensation for DFB’s to be finalised
• Instrumentation & controls to be available & more reliable
• Test of specific tool QUI to separate installation/operation
• Helium inventory & strategy to be confirmed
OK, Faster at sector 4-5, to be continued
When conditions OK
Done for 8 arcs, singularities
being treated
OK, to be continued
OK, to be continued
Done, no longer required
Defined, to be implemented
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LT836LT837
LT864LT865
LT866LT867
DFB Commissioning: levels and anti-condensation
≈ 5 m
Consolidation of DFBs
Anti-condensation system6 kA, 13 kA, 600 A- dry air protection: current lead insulating flange + top of chimney
flange, connected in series. Interim solution for sector 4-5120A - active heating system + dry air (depending on tests)
6 kA, 13 kA (322) 600 A (178) 120 A (36)
Liquid helium level gauges- Installation of calibrated level gauges. - Installation of a protective box around the level gauges
Protective box
Dry air protection of 600A chimneys of DFBAH
Configuration of LG
S. Claudet - 06Dec'07 LHC-MAC22 - Cryogenics
Commissioning DFBs of sector 4-5
report date: 04.12.2007 ← Point 4 Point 5 →
DFBMK DFBML DFBMG DFBAH-L DFBAH-H DFBAI-H DFBAI-L DFBLD DFBXE
Monitoring tasks
Current lead temperature readings n.a.
Current lead head heating system n.a.
DFB liquid level readings n.a.
DFB pressure readings n.a.
DFB temperature readings n.a.
All instrumentation functional n.a.
Commissioning-specific tasks
Lead flow control tuning at 50 K n.a.
Insulator + CL free of condensation at 50 K for 24 hours n.a.
Liquid level control tuning n.a.
Boiloff test to verify LL probe calibration and calculate heat load n.a.
Level gauges set points confirmed n.a.
ELQA passed n.a.
Cryo Start/Cryo Maintain n.a.
Authorization for pow ering n.a.
DFBMK: boil-off cross-check to be finalized
DFBML: released for ELQA
DFBMG: released for powering
DFBAH LCM: liquid level confirmed- abnormal behaviour of several control
valves for 600A CL
DFBAH HCM: liquid level confirmed- abnormal reading of temperature sensors of 13kA CL #1
DFBAI HCM: liquid level cross-checking in progress- Liquid level control to be tuned. DFBAI LCM: liquid level confirmed- abnormal behaviour of several control
valves for 600A CL. Several valves had to be replaced by caps!
DFBLD: boil-off performed- Liquid level control to be tuned.
completed
in progress / scheduled
IR4R IR5L
S. Claudet - 06Dec'07 LHC-MAC22 - Cryogenics
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Content• Introduction• Main facts from sector 7-8 (January to July
2007)• Last projects towards completion• Identified weak points (@MAC21) and status• Cryo HWC activities since Mid 2007• Action plans• Summary
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Flushing sectors before cool-down
Dust Debris Kapton Reports
And possible shorts in diodes !
But the sooner the best !!!
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC - 1st cool-down sector 4-5
04-Jul11-Jul
18-Jul25-Jul
01-Aug08-Aug
15-Aug22-Aug
29-Aug05-Sep
12-Sep19-Sep
26-Sep03-Oct
10-Oct17-Oct
A7R4
A7L5
60
80
100
120
140
160
180
200
220
240
260
280
300
320
Temperature [K]
Date
Arc Cells
300-320
280-300
260-280
240-260
220-240
200-220
180-200
160-180
140-160
120-140
100-120
80-100
60-80
P4
P5
6 weeks stand-by: looks promising
Two hoses in DFBA’s became leaky during
cool-down
Cool-down stopped twice due to leaks during cool-down
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC sector 4-5: 1st Cool-down (2007)
0
50
100
150
200
250
300
350
29-Jun-07
13-Jul-07
27-Jul-07
10-Aug-07
24-Aug-07
07-Sep-07
21-Sep-07
05-Oct-07
19-Oct-07
02-Nov-07
16-Nov-07
30-Nov-07
14-Dec-07
Time [days]
Tem
pe
ratu
re [
K]
Return Temperature to 4.5K Refrigerator Magnet Temperature (average over sector)
4.5K Refrigerator Supply Temperature
LHC Sector 4-5: 1st cool-down (2007)
1st leak and repair 2nd leak
and repair
Cool-down to 1.9K
Powering tests
Cryogenic tuning
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
0
12
3
45
6
7
89
10
1-Jan-04 19-Jul-04 4-Feb-05 23-Aug-05 11-Mar-06
Tem
pe
ratu
re [
K]
4.5K Refrigerator supply temperature
Magnet temperature (average over sector)
1.8K Refrigeration unit cooling temperature
LHC 45: Cryogenic tuning toward 1.9K
Cryogenic tuning at 1.9K
Stops due to external sources Stops due to 1.8K units with small air leak in cold sub-atmospheric circuit
Last 4 weeks (6Nov’07 to 5Dec’07)
With contractor
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
LHC sector 5-6: 1st Cool-down (2007)
0
50
100
150
200
250
300
350
16-Nov-07 23-Nov-07 30-Nov-07 07-Dec-07 14-Dec-07
Time [days]
Tem
pe
ratu
re [
K]
4.5K Refrigerator Supply TemperatureMagnet Return Temperature to 4.5K Refrigerator
Temperature (average over sector)
Cool-down of other sectors
7-8 & 8-1: start wk51 for Jan’08
5-6 & 6-7: Restart wk05 2008
And four remaining sectors Feb’08 to Apr’08
7-8 & 4-5: 1st cool-down in 2007
5-6: 300K-80K Nov-Dec 2007
Short in diode and repair
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Content• Introduction• Main facts from sector 7-8 (January to July
2007)• Last projects towards completion• Identified weak points (@MAC21) and status• Cryo HWC activities since Mid 2007• Action plans• Summary
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
On-going actions & plans
• Cool-down process & Heat loads to be further checked and analysed
• Refrigeration: Ex-LEP upgrade consolidations and 1.8K units • Instrumentation & controls to be terminated and consolidated • LHe level / anti-condensation for DFB’s to be deployed• He guard along sectors to be consolidated• Few other consolidations to be evaluated
• Operation procedures and teams know-how to be re-inforced• Strategy for Helium inventory defined, to be implemented
LHC-MAC22 - CryogenicsS. Claudet - 06Dec'07
Summary• The LHC cryogenic system is progressively
being commissioned, with signs of “learning curve”
• Consolidation program started (JT valves, DFB’s, controls, helium) and to be continued
• 2007 has been a difficult year of commissioning, and most likely 2008 will be a difficult year towards the expected first beams and collisions
• Looking forward to “routine” operation !!!