2. LHC Performance Workshop (Chamonix 2016)
Cryogenics
Sessions 3 : LHC Hardware Performance
G. FERLIN on behalf of TE-CRG group
With contribution from K. Brodzinski, S. Claudet, D. Delikaris, L. Delprat, E. Rogez and L. Tavian

3. Agenda Hardware status and Availability 2015 Performance aspect 2016
Expected Hardware performance 2016
Improvement foreseen all along the year
Cryogenic power studies
BS thermal load
IT movement investigation
26 Jan 2016
TE-CRG-OA

4. Hardware configuration 2015
Run2 configuration
Two 4.5 K cold boxes + one cold pumping unit except P18/P2 w.r.t scenario for Run 1 (1 Cryoplant /2 sectors)
Pro
Additional installed capacity for BS scrubbing
Better availability expected (less rotating component running).
One parallel quench/sector could be recovered without delay
Lower energy consumption (-2 MW) as collateral bonus
Cons
In case of multiple quenches in parallel (more than 3 cells !!!) , the recovery time should be affected. (never occurs during 2015)
In case of 1.9 K trip, two sectors will be lost. (never occurs, as mostly seen in S12/S23 not concerned by this configuration)
Tuning of this new configuration at P18/P2 not yet possible.
More than 3 parallel quenches will increase the recovery delay
26 Jan 2016
TE-CRG-OA

5. Overall Availability 2015 [Cryo Maintain]
Statistic for run 2 from April 5th to Dec 14, TS excluded
Supply failures mainly during spring (Post LS1 effect
Users failures mostly due to 6.5 TeV
Downtime in line with Run 1 despite higher beam induced heat loads
26 Jan 2016
TE-CRG-OA

6. Overall Availability 2015 [Cryo Maintain]
Statistics in line with our Cryo monitoring
Downtime is to be considered as average for each category.
PLCs: average downtime = 18h12min /// frequency = 1 every 2 months
Cold Compressors: average downtime = 6h34min /// frequency = 1 every 3,5 weeks
OP / Human Factor: average downtime = 4h32min /// frequency = 1 per month
Elec / Instrum / Tunnel: average downtime = 1h45min /// frequency = 1 every 10 days
DFBMI: average downtime = 0h4min /// frequency = 1 every 2 days
DFBAF: average downtime = 0h3min /// frequency = 1 every 4 days
4 contributors for
75% of total cryo downtime
Most frequent contributors
OP factor: Mostly new OP staff (<30% experienced with Run 1) and no more capacity margin
26 Jan 2016
TE-CRG-OA

7. Overall Availability 2015 [Cryo Maintain]
Downtime per categories and mitigation action undertaken
Most frequent CM losses: - DFBMI: 39 losses; Should be solved during YETS - DFBAF: 29 losses; Trigger origin should be discussed with stakeholders (thresholds, timer…)
Most time-consuming CM losses: K units: 8 losses, Average equivalent to Run 1; should devrease if new configuration P18/P2 works well.
- PLCs: 4 losses, should be solved with new firmware during YETS - OP/Human factor: 9 losses; should be partially solved by process optimization under high BS load
- Elec/Instrum/Tunnel: 22 losses; Average equivalent to Run 1
26 Jan 2016
TE-CRG-OA

8. Hardware reliability 2015 2015 Hardware reliability for Cryoplants 0.7
0.8
0.3 2
1.5
1.8
1.6
Failure rate / unit / year
26 Jan 2016
TE-CRG-OA

9. Hardware reliability 2015 Hardware fault breakdown
In line with 2012 good data + “Supply” in spring and Cryo PLC’s (Treated in TS or YETS)
Multiple origins, less straight forward to improve
Hardware fault in line with Run 1
26 Jan 2016
TE-CRG-OA

10. Hardware status 2015
Refrigeration Main hardware issue solved during YETS
warm compressor degradation diagnosed preventively and replacement without damage nor impact
Major leak on 18 kW plant
3 turbines failure, No impact, compensated by Liquid Nitrogen
26 Jan 2016
TE-CRG-OA

11. Hardware status 2015 Refrigeration: YETS improvement
Distributed failures
16 valves for turbine Control
4 Cryo PLCs
Activated charcoal replacement (P6/P4/P8);
Risk identified with some oil removal systems, worth the effort and follow-up
Software update all around LHC
Partial Cold Compressor VFD & AMB exchange
24 VDC consolidation
…….
26 Jan 2016
TE-CRG-OA

12. Performance aspects
26 Jan 2016
TE-CRG-OA

13. Expected Hardware performance 2016
W/hc
p+/bunch
bunch number
installed capacity limit for K
installed capacity + margin form 1.9K unit at lower flow than designed
limit S23
36 bunch trains
72g72 bunch trains
144 bunch trains
72 bunch trains
cleaning
s12, 23, 81, 78 85
Theoritical LHC nominal heatloads
cleaning
s34, 45, 56, 67
after 8b4e bunch train test
In 2016 we will be able to provide at least the same capacity as in 2015
26 Jan 2016
TE-CRG-OA
K.Brodzinski_6th Evian_

14. Expected Hardware performance 2016
Main improvement foreseen all along the year
Software improvements to fulfill the cryogenic power increase (continued effort as in 2015
Automatic adaptation to follow the thermal load on BS (must be tuned online!)
Tuning of installation to prepare a scheme for high load
Anticipation of the thermal load before beam
Smooth Decrease of the thermal load by electrical heating after dump
For FDBAF, a new settings of the threshold (absolute value and timer) should decrease drastically the quantity of losses of the Cryo Maintain signal. …
“Data mining” to anticipate possible issues on tunnel components (1st studies started last year with former EN-ICE); On & Off line tracking of process deviations and abnormal behavior.
12 Jan 2016
TE-CRG-OA

15. Expected Hardware performance 2016 Hardware configuration
This configuration will be tested before the end of YETS 2015
The aim is to decrease the number of rotation machine to improve the global availability
The second target is to boost the cooling power of the Cryoplant in P2 and consequently the BS cooling power for the S23(cooling capacity margin to be evaluated during tests, to be used in addition to previously defined actions for S23)
Specific configuration with non symmetry
12 Jan 2016
TE-CRG-OA

16. Cryogenic power studies
BS thermal load (Maximum plant power validation)
Due to a limited margin for sector S23 the proposition consists to define a road map to increase the margin and to reach the ultimate power;
A first step consists to perform a power survey of the Cryoplant unit not connected to sector in P2 (same power survey for the twin plant in P8). (already foreseen during the restart of the plants).
The second step consists to
Perform a maximum BS load on the sector by using electrical heater installed on BS circuits.
In parallel, perform the same test on the twin plant installed in P8
This second step is not included in the YETS time schedule and should be included if confirmed (3 to 4 days)
12 Jan 2016
TE-CRG-OA

17. Cryogenic power studies
BS thermal load (Process upgrade to reach higher power)
Cryogenic power recovery by using cold bypasses and associated issue / propositions
Theoretical interest: Recover cooling power for BS cooling
A new test is foreseen at P2 (see slide above)
Practical limitations of this scheme do not shows a high margin on measured sectors
This operation scheme was not foreseen originally. Hardware modification are necessary to be able to use this configuration with higher effects on all points. A prototype should be installed during EYETS and after validation the 3 others installation should be updated during TS2
12 Jan 2016
TE-CRG-OA

18. Cryogenic power studies
He storage
Compression
Compression
Refrigerator
(economizer)
Refrigerator
(liquefier) A B
1.9 K circuit
1.9 K circuit
4.5 K circuit
4.5 K circuit
Magnets supply
Magnets supply
12 Jan 2016
TE-CRG-OA

19. Cryogenic power studies
ITR8 movement investigation
In order to investigate the ITR8 oscilation, a step by step check sequence is proposed to identify concerned circuit if any
This sequence should be:
Adjust Pressure difference with DFBX to stop refilling
Block all valves
Validation the oscillations during a significative period.
This sequence is not yet planned and needs 2 to 3 days to be done (possibly during powering test of the sector?)
12 Jan 2016
TE-CRG-OA

20. Summary
For 2016, Cryo team expect a global availability in the range 93 to 95 % with CRG origin fault below 5%
Beam Screen heat load mitigation
Installed power ~110 W/h-cel, 160 W/h-cel already reached except S23 with plan to understand the lower margin
Software optimization on going to fit with 2800 bunches
Data mining to detect online smooth drift and anticipate possible issues.
Proposition to test an upgraded cold by-pass, during EYETS, for recovering additional margin.
26 Jan 2016
TE-CRG-OA