Post on 08-Jan-2016
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LHC CryogenicsHWC day 19 March 2009
Serge Claudet TE-CRG-OA
(LHC Cryo OP)
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Content
• Introduction: experience gained so far
• Consolidations and re-commissioning
• Calorimetry
• Organisation and staff matters
• Summary
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
First cool-down of LHC sectors
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12-Nov-2007
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07-Jan-2008
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Temperature [K]
ARC56_MAGS_TTAVG.POSST ARC78_MAGS_TTAVG.POSST ARC81_MAGS_TTAVG.POSST ARC23_MAGS_TTAVG.POSST
ARC67_MAGS_TTAVG.POSST ARC34_MAGS_TTAVG.POSST ARC12_MAGS_TTAVG.POSST ARC45_MAGS_TTAVG.POSST
Christmas and water maintenance shut-down
Short in connection
cryostats and repairs
Ope
n Da
ys
Cooling sectors + Cryo tuning + Powering activities
UX85 Ph1
works
All sectors at nominal
temperature
Simultaneous Cryo start/maintain
First beams around LHC
8 sectors - 8 months
Tuning: ≈ 6 wks / sector
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
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LHC Cryo Maintain
LHC Cryogenics: towards beamsTarget for global (8 sectors)
“Cryo OK for Powering”
UX85 Ph1
worksElectrical
Transformers
Cool-down and commissioning
(systems, instrumentation, logic)
Beams !!!
19 Sept’08Cryo conditions for 3 months of intense HWC
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
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LHC Cryo Maintain
LHC Cryogenics: just after beams
Target for 4 sectors tested with calorimetry
A bit frustrating !!!
19 Sept’08
Switch EL network
Rather good stability without specific efforts
A dream for HWC w.r.t Spring’08 !!!
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Experience gained so far
• All cryo-subsystems were tuned and put into service (if it has worked once, it will come back)
• Procedures established and teams trained
• Weak points identified and consolidation programs established:– Already visible in 2008 for EL, CV, CO, Cryo– Continued since with many support teams
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Tuning LSS components• Electrical Feed Boxes (DFBs):
– We could operate all of them close to nominal conditions (maximum scenario required so far during HWC)
– Few delicate cases (heat loads, levels measurements, levelling of sc link to magnets, valves for cooling current leads, thermometers and noise, High Voltage perturbation on instrumentation cards)
• Stand alone Magnets (SAM):– Difficult Level measurements due to Cold GHe capillary with too
small diameter and possible low points, most delicate cases being treated
• Triplets:– DFBX: Commissionned with moderate ramp rates on some leads
(Cu)– NC found on some Q1 (Missing Cu braid), being treated on critical
cases in R1 and 5L
• Superconducting links (DSLs):– No problem encountered on four DSLs (<80m),
except for DSLC_P3– DSLC design/installation weak point being treated
Might come back !
Nothing special expected for re-testing of Y-lines or DSLC
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Electrical feed boxes (DFB’s)
QRL
• On-going work on valve positioners (and plugs ?)
=> Expected gain in stability
- Rangeability of all valves tuned - Filters installed ahead of all valves
=> Effects already confirmed @ P8
Current leads
control
Filling valve
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Levels for stand-alone magnets
2008: Case by case lengthy tuning AND global QRL_line_D pressure stability required
LSD0809: Pipe work being consolidated for most cases
2009: At least first sector to be re-assessed with complete boil-off tests, should become more straight forward once consolidation validated
Reference: P6 already conform, due to specific design due to beam dump line
Old small diameter capillary
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Calorimetry• Operation:
– Establish global stable conditions, with specific settings for cooling and filling valves
– Almost on-line assessment of temperature drifts (mK/hr) mostly to validate the test or identify possible non-standard zones
• Analysis (off-line so far):– Evaluation of the power deposited in helium (internal
energy) to define the total resistance of a cryo sub-sector, and by comparison quantify singularities.
– Specific studies required to confirm the origin of the singularities
Manual tuning
So far manual, drifts to be
included in supervision
So far manual
(Timber & XL)
Many specific cases (cryo cells, instrumentation, operation facts and accuracy) being considered, so far with success
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Standard cells (≈27/sector)
QRLFilling valve
Q D DD
• Preparation from 1.9K operation: 2-3 days to set-up conditions
• Test configuration: 4-5 hours before ramping current
Q D DDQ D DDQ D DD
Magnets 1.9K control
Beam screen T control
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Arc sub-sector resistance variation assessed by calorimetry
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Sub-sector resistance variation w/r to baseline [nΩ]
(5 )Dipole arcs (4 )Quadrupole arcs
NNXN: Confirmed by electrical measurements
23R3
15R131
R6, 3
1R1
31R7
~ 2 W @ 7 kA
Although we try to reduce our uncertainty, we feel that specific behaviour of DS zones would be of greater interest!
Triplets: being tested right now @P8
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
“Cryo view” of tasks ahead this year
Challenges for this year:
Completion of consolidations (like others!)Cooling 4 sectors + filling/tuning 8 sectors in four months !!!
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Affectations LHC Cryo CRG-OA
Ing. OP référents experts académiques
Ing. production Encadrement site
Opérateurs Sites + ShiftsCCC
interface
Site coordination
HWC
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
LHC Cryo shifts 2009: 15 Avril
Final adjustments being implemented
Timing:6h - 14h - 22h
(+/- 1/4h over-lap)
Tel Cryo CCC:70463-70464
+ Additional support am/pm (2x2 pers.) for CCC or LN2 logistics
+ Double on-call service for interventions + Eng. Support via “Best Effort”
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Proposal for definition of tasks site/shifts
We will adapt to reality and needs for global efficiency
Winter’09 Spring’09 Summer’09 Aut’09
CCC for Cryo Start/Maintain Direct interface for BE/OP
Local CCR for support and site periodic activities
CCC for global overview and continuity of activities
Local CCR for cool-down, tuning and HWC activities
PP BeamsCooling-Tuning-HWC
Cryo shifts in CCC
Being reviewed and more closely precised
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Summary• LHC Cryogenic system has been put in operation with
success in 2008 and was “ready” for 5 Tev operation
• Since september 2008, test programs were conducted and improved our understanding and tuning of sub-systems (calorimetry, 1 refrigerator on two sectors)
• Consolidation programs were launched to improve safety and to increase availability (to be completed)
• We should manage foreseen program with less stress, but we know we have about 500 PID control loops per sector to be active simultaneously, and we will have surprises and temporary down-time to be dealt with!
Complements
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Cryo conditions for powering
Cryo Start: set of conditions to allow powering of concerned sub-sector (rather strict = good stability of process)
Cryo Maintain: Few important conditions checking integrity of HW, with slow power abort in case this signal is lost CM: No adjustment possible
during operation
CS: Adjustments within pre-set limits
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Recovery Time after Limited Resistive Transitions
• More than 14 cells or full sector: recovery up to 48 hours• In case of fast discharge (even w/o quench): 2 h recovery (heating due to
eddy currents).
(Predictions at design stage)
Achieved or achievable
From x3 down to x1.5 w.r.t design values
Without loosing helium, and powering permit on other powering subsectors
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
St Genis-PouillyFerney VoltaireGexGenevaPoint 2Point 4Point 5Point 6Point 7Point 8P 1P 1.8Point 32 forCMS(R)
Helium storage
50 t: 50 x 250 m3 + 40 x 76 m3
30 t: 2 x 15 t for Spring 2008 !
Now completed by (Ph. 1):
A good basis, but “rather long” logistics
7832
10 5 5
Cold massesQRL, header CQRL, other headersCryoplantsStorage tanks
LHC: 130t
S. Claudet LHC Cryogenics - LHC HWC day - Mar'09
Two sectors on one cryoplant
Distribution Line Distribution Line
Magnet Cryostats Magnet Cryostats
Cold Compressorbox
Warm CompressorStation
Cold Compressorbox
Warm CompressorStation
Shaft
Sur
face
Cav
ern
Tun
nel
LHC Sector (3.3 km) LHC Sector (3.3 km)
1.8 K Refrigeration Unit Ex-LEP 4.5 K Refrigerator New 4.5 K refrigerator 1.8 K Refrigeration Unit
Upper Cold Box
Warm CompressorStation
Lower Cold Box
Warm CompressorStation
Cold Box
Interconnection Box
Powering tests Powering tests
4.5K 15 mbar
4.5K Ref.: ≈10% capacity left per sector for dynamic loads, after specific adjustments made
≈ 5MW of power input, instead of 8MW (2x4MW)
Competitive for recovery after stops (<10hrs for CC, <24hrs after power failure for 2 sectors)
Not valid for large transients, but an interesting feature for low beam loads, or validated fall-back scenario if serious problems with a refrigerator
OK P6, possible P8 (3Qx) P4 ? (RF/DSLC),
P2/P18 ?!? (ex-LEP, 3Qx)