1. 2 K Coldbox Safety and ESH
Vishy Ravindranath
LCLS-II 2 K Cold Box FDR
March 9, 2017

2. Outline 2K Cold Box Safety Reliefs Other safety considerations
FMEA & What-If analysis
Summary
LCLS-II 2 K Cold Box FDR, Sept 27, 2016

3. 2K Cold Box Safety Reliefs- Design Philosophy
2K Cold Box Safety Reliefs are designed to:
Adequately relieve the system and protect the process pipes/components within the 2K Cold Box against worst case failure scenarios.
Relief Valves mounted within Guard Vacuum Enclosure: (protected by parallel plate with 2 psig set pressure): Prevents contamination of sub-atmospheric process lines during normal operations
3. All reliefs vent into a common relief header which is routed outside the building to vent the gas in a safe manner
4” Relief Discharge Collector
LCLS-II 2 K CBX FDR, Mar 9, 2017

4. 2K Cold Box Safety Reliefs
Sub-atmospheric pressure He gas from cryomodules returns to the suction of CCs and is compressed from ~ 27 mbar to 1.2 bar in the 2 K coldbox. The compressed gas returns to 4.5K coldbox through an U-tube.
For the test of 2 K CBX with LHe dewar, 4.5K cold vapor from LHe dewar is used to simulate the flow, with a 3 kW heater for controlling the helium temperature in the suction line.
A bypass line for the overall CC train is included for 4.5K standby operation mode and pumping down.
Safety valves are used for the protection of the 2 K coldbox, CC and process piping.
Pressure and temperature measurement are installed at the suction of each CC and on the discharge pipe.
A flow meter is installed in the discharge pipe of CCs for flow measurement and controlling of CC.
The 2K coldbox provides vacuum insulation for the cryogenic part of CCs and the cryogenic process piping.
Clean up and warm up piping are included.
Utility piping (Instrument air, cooling water and guard vacuum) are included.
Seven thermal relief valves protect the pipe volume between
Dewar 4K Supply Bayonet & PV : RV41500 (75 psig)
Process pipe volume between the control valves : RV41510 (75 psig)
CC1 suction bayonet & CC1 discharge bayonet : RV41520 (45 psig)
CC2 suction bayonet & CC5 discharge bayonet : RV41530 (45 psig)
CC6 suction bayonet & PV : RV41540 (45 psig)
CC6 bypass bayonet and control valves : RV41550 (75 psig)
PV41170 & 30 K return to 4K CBX bayonet : RV41560 (75 psig)
Guard Vac.

5. Codes for Safety Relief Sizing
Standards & References:
API 520 – Part I 2014, “ Sizing, Selection, and Installation of Pressure Relieving Devices on Refineries, Part I-Sizing and Selection”
CGA S “Pressure Relief Device Standards”
ASME Code Section VIII, Division I, Appendix 11, Mandatory Capacity Conversions for Safety Valves
Technology of Liquid Helium, edited by R. H. Kropschot, B. W. Birmingham, and D. B. Mann, National Bureau of Standards Monograph 111 (1968).

6. Safety valves Primary relief valve requirements
RV41500/RV41510/RV41520/RV41530/RV41540/RV41550/RV41560: Thermal expansion of trapped cold gas during a loss of insulating vacuum incident.
RV41712: guard vacuum enclosure relief valve, sized for the worst case assuming all reliefs vent at the same time, maximum flow = 2 kg/s
RV41000: Vacuum Jacket protection, sized for 1.5 x maximum cold compressor flow rate (300 g/s)
The detailed calculations are documented in : “Ref: P K Cold Box Relief Valves”
LCLS-II 2 K Cold Box PDR, Sept 27, 2016

7. Pressure Drop in Relief Discharge Line- Single Relief Valve Relieving
ΔP = 0.2 psi
ΔP = 2 psi
ΔP = 0.4 psi
3” relief discharge manifold
Pressure Drop in the vent line calculated for the maximum relief flow from a single relief valve – 800 g/s (RV41530, Set Pressure = 45 psig)
Total Pressure Drop in the discharge header = 3 psi
4” Relief Header
ΔP = 0.5 psi
Vents to outside the Bldg.
LCLS-II 2 K CBX FDR, Mar 9, 2017

8. Pressure Drop in Relief Discharge Line- All Relief Valves Relieve Simultaneously
ΔP = 1 psi
ΔP = 2 psi
ΔP = 2 psi
3” relief discharge manifold
Failure scenario:
- 2K Insulating vacuum is compromised, Multiple trapped volumes & all reliefs vent simultaneously (total flow rate = 2 kg/s).
Total pressure loss in relief valve discharge line = 8 psig, relief valve discharge pressure = 45 (set pressure) + 8 = 53 psig.
With air in the insulating vacuum space, the differential pressure acting on the cold compressor casing/piping = 53 psid
Cold compressor casing design pressure = 60 psid.
4” Relief Header
ΔP = 3 psi
Vents to outside the Bldg.
LCLS-II 2 K CBX FDR, Mar 9, 2017

9. Other Safety Issues ODH: 2K Cold Box located in the cold box building
Cryo building: class I ODH
Warning Signs
Installed Oxygen Monitor
Ventilation
Training for personnel
2. Noise: The expected noise generated by all the cold compressors will be lower than 85 dB when measured from 1 m distance from equipment- no hearing protection needed inside the cold box room
The standards for occupational noise exposure adopted by the DOE State that personnel without hearing protection must not be exposed to an intensity of noise exceeding 85 dBA.
3. Cold burn: The cryogenic pipes and equipment are vacuum insulated, no exposed cold piping.

10. Other Safety Issues Work Platform
4. Fall protection: Cold Box Height: 12.5 feet
A platform around the 2 K coldbox facilitate safe access to the components located on the top shell of the 2K Cold Box
Confined space: The current 2K cold box design minimizes the requirement to work within the 2K CBX vacuum enclosure.
LCLS-II 2 K CBX FDR, Mar 9, 2017

11. 2K Cold Box-Failure Modes and Effects Analysis
“Failure Mode and Effects” Analysis for the 2 K CBX has been performed and documented in D2001 (under review).
2K Cold Box analyzed for all single and probable multiple (equipment or operator) failures that could cause personnel injury or significant equipment damage or loss of system functionality/diagnostic ability.
The FMEA (Failure Mode and Effect Analysis) individually lists each anticipated failure mode for each component.
Each failure entry explains the hazard, mentions the existing safeguard against the hazard & makes a recommendation that will eliminate the hazardous condition.
LCLS-II 2 K CBX FDR, Mar 9, 2017

12. 2K Cold Box-What-If Analysis
What-If Analysis for the 2 K CBX has been performed and an EN D2002 was drafted.
LCLS-II 2 K CBX FDR, Mar 9, 2017

13. Summary
The related ES&H aspects are identified and addressed in the 2 K cold box design.
Relief Valve calculations have been performed for the 2K cold box. The calculation details have been documented and reviewed.
What-if & FMEA analyses documents currently under review.
Document No.
Title
Author
Status
79222-P0001
2K Cold Box Relief Valves
V. Ravindranath
Released
79222-D2002
LCLS-II 2K Cold Box What-If Analysis
H. Bai
Under Review
79222-D2001
LCLS-II 2K Cold Box Failure Mode and Effects Analysis
LCLS-II 2 K Cold Box PDR, Sept 27, 2016

14. Questions ?

15. Back-Up
LCLS-II 2 K CBX FDR, Mar 9, 2017

16. Pressure rating of components-Interfaces
[1] LCLSII-4.8-EN-0791-R0, Jlab bayonet gate valves
[2] ALAT C4118-NT-004 (2) “Mechanical & Electrical” for the LCLS-II 2K Cold Compressor
Int No.
Components
Bayonet Size
Pressure Rating [psig]
Design Temperature [K]
Note
He-501
2K return from Interface Box to CC1 suction
9-1/4”
60.4
4-300
[1]
He-502
CC1 discharge to CC2 suction
He-503
2K return from Interface Box to CC2 suction
He-504
CC5 Discharge
5-3/16”
75.1
He-505
CC6 Suction
He-506
CC6 Bypass
He-507
30K return from 2K Cold Box to 4K Cold Box
He-508
4K vapor supply from LHe storage dewar to CC1 suction
3-1/8”
83.2
Cold Compressor Motor Cartridge
660 psig [47 bara]
[2]
Cold Compressor housing
60 psid [4.1 bar d]
LCLS-II 2 K CBX FDR, Mar 9, 2017