lhc hardware commissioning safety training day s. claudet (at-acr-op) with great help from g....
TRANSCRIPT
LHC HARDWARE COMMISSIONING SAFETY TRAINING DAY
S. Claudet (AT-ACR-OP)
With great help from G. Lindell (Safety commission)
CRYOGENICS
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Content• IntroductionLHC Cryogenics - What are the risks ?
• LHC strategy for oxygen deficiency hazards (ODH)Specification, procedures, Level 4 safety course
• Cold surfaces and adapted behavior
• Access restrictions during between 300 K - 80 K
• Interventions on helium circuits (cryo work permit)
• Summary
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
QSCB
Sector 1-2 Sector 2-3 Sector 3-4 Sector 4-5 Sector 5-6 Sector 6-7 Sector 7-8 Sector 8-1
QSRB
QURA
QUIAQUIB
Point 4Point 2Point 1.8 Point 6 Point 8
Surface
CavernQURC
QSCA QSCA QSCB
QSRB QSRB
QSCB QSCAQSCA QSCB
QSRB
QURC QURC QURC QURC
QUIC QUIC
QURA
Shaft
QSCC QSCC QSCC QSCC QSCC
Tunnel
Storage Storage Storage Storage Storage
QURAQURA
Legend
Cryogenic Distribution Line
QSC_(A,B,C):QSR_(A,B):QURA:QURC:QUI_(A,B,C):
Warm Compressor StationSurface 4.5 K Refrigerator Cold BoxUnderground 4.5 K Refrigerator Cold Box1.8 K Refrigeration Unit Cold BoxCryogenic Interconnection Box
Commisionned & accepted
Under commissioning
Delivered / Under installation
Under fabrication
Ordered (Contract placed)
Under definition
Electrical Feed Box
Superconducting Link
QURC
QSCC
QSRA QSRA QSRA QSRA
QURC
QSCC QSCC
QURC
QUIC
LHC cryogenics architecture
Helium @ 1.9 K
- Helium
- Modularity
- Single cryo line along the machine
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Warm Recovery Line
Helium Ring Line
- Pressure vessels (code D2) with appropriate materials and safety devices
- No Nitrogen in underground areas
- QRL header D as large acceptance discharge line to avoid local discharges
- No circulator underground
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Major hazards associated with cryogenics (IS47)
• Asphyxia: Oxygen is replaced by another gas (floor or ceiling depending on density)
• Burns: Contact with cold surfaces could burn, (cold burns) as if it was hot surfaces
• Explosion: After heating to ambient temperature, 1l of liquid will be at 700 atm or more
• Materials: Material properties change radically with temperature: shrinkage, fragility
Risk
dur
ing
oper
atio
nAd
apte
d de
sign
Risk
dur
ing
Inte
rven
tions
+ Interventions on part of the helium circuit: Could be under pressure, cold or about to be pressurised
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Content• IntroductionLHC Cryogenics - What are the risks ?
• LHC strategy for oxygen deficiency hazards (ODH)Specification, procedures, Level 4 safety course
• Cold surfaces and adapted behavior
• Access restrictions during between 300 K - 80 K
• Interventions on helium circuits (cryo work permit)
• Summary
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Oxygen Deficiency Hazards (ODH): risksLHC Project Report 523: Oxygen deficiency hazard (ODH) monitoring system in the LHC tunnel
• Tunnel ventilation, curvature, alcoves• Worst case scenario analysis• Experimental studies, validation
• Recommendations: detection + training
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Oxygen Deficiency Hazards (ODH): Engineering specification
LHC-SG-ES-0001 rev 4.0
EDMS 398629
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Oxygen Deficiency Hazards (ODH): Complement for specific cases
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Oxygen Deficiency Hazards (ODH): Cryogenic safety level 4 course
• Required for LHC HWC activities underground• Web based course available (incl. movie): SC’s home page / safety training / level 1, 2, 3 &4
and FAQ for help
ODH = Oxygen Deficiency Hazard(Lack of oxygen)
21 % O2
18 % O2
0 % O2
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Oxygen Deficiency Hazards (ODH): Cryogenic safety level 4 course
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Content• IntroductionLHC Cryogenics - What are the risks ?
• LHC strategy for oxygen deficiency hazards (ODH)Specification, procedures, Level 4 safety course
• Cold surfaces and adapted behavior
• Access restrictions during between 300 K - 80 K
• Interventions on helium circuits (cryo work permit)
• Summary
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Cold burns
• Surfaces could become cold• How to detect it could be dangerous:
This also applies to “cold vapour clouds” and your lungs !!!
Condensation of air
Simply avoid contact with cold « white » surfaces
wet
Skin do not detach !Cold burns
WHI
TE
COLO
UR
Condensation of water
Ice
T
0 C
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
1st Cool-down to 80K or Warm-up:Engineering specification
LHC-S-ES-0003 rev 2.0
EDMS 615783
Limit at 80 K due to characteristics of thermal contraction of materials
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
1st Cool-down to 80K or Warm-up
• If required and validated by HWC coordinator as a must, blue token for doors could be granted from local cryo control rooms
• Otherwise,access defined by HWC Engineering Specifications such as LHC-S-EC-00017 rev 1.2 (EDMS 848560) for S4-5
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Content• IntroductionLHC Cryogenics - What are the risks ?
• LHC strategy for oxygen deficiency hazards (ODH)Specification, procedures, Level 4 safety course
• Cold surfaces and adapted behavior
• Access restrictions during between 300 K - 80 K
• Interventions on helium circuits (cryo work permit)
• Summary
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Cryogenic work-permit: When/ What for ?
• After the pressure test, interventions (opening, cut, welding) on helium circuits have to be secured by the cryogenic operation team. For this, a cryogenic work permit with corresponding consignation has to be issued
• For purge, evacuation and pressurization of circuits which are not consigned, work permit is not required. (they are self protected)
• The cryogenic work permit covers only risks related to pressure, cold burn and oxygen deficiency after the pressure test, when the initial circuit configuration is complete and the tunnel circuits are connected to the interconnection box.
• For other risks (electrical, fire, …), relevant authorizations or consignations are required (a cryogenic work permit is necessary but not sufficient to safely weld on helium circuits of a DFB which has also electrical and fire hazard)
+ Interventions on part of the helium circuit: Could be under pressure, cold or about to be pressurised
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Cryogenic work-permit: stakeholders• The requester: Project Engineer (PE) or Installation Supervisor
(IS) (according to the A9 safety code) is responsible for:– documentation and information supply (P&ID, drawings…)– Communication of the intervention completion.
• The Intervention Team Leader (ITL) in charge of: – the work execution (CERN or sub-contractor).
• The Operation Engineer (OE) (one per cryogenic island). Responsible for:– Definition and validation of the consignation procedure.– Execution of the consignation of the circuits– Communication of the consignation and deconsignation
completion.
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Cryogenic work-permit: how/where ?
EDMS 754940
To be updated and finalised
Point 2 (2007) Udo wagner + Jean-Paul Lamboy + SdC 79240/79241Point 4 Udo wagner + Jean-Paul Lamboy + SdC 79440/79441Point 6 Gérard Ferlin + Steffen Junker + SdC 79640/79641Point 8 François Millet + Lionel Herblin + SdC 79840/79841
SC - 18 Oct'07 LHC HWC safety training: Cryogenics
Summary• For LHC underground areas, be sure you have followed
« cryogenic safety” level 4 course and that you know what to do in case !
• Never touch a cold « white » surface• Access is not systematic between 300 K and 80 K• Get a valid « Cryo work permit » prior to any
intervention on a helium circuit
Once you have applied the required procedures
Safety is often a matter of initiative and common-sense