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

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

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

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 & PV41500 : 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 & PV41160 : 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.

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-1.3-2008 “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).

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: 79222-P0001 2K Cold Box Relief Valves” LCLS-II 2 K Cold Box PDR, Sept 27, 2016

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

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

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.

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

2K Cold Box-Failure Modes and Effects Analysis “Failure Mode and Effects” Analysis for the 2 K CBX has been performed and documented in 79222-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

2K Cold Box-What-If Analysis What-If Analysis for the 2 K CBX has been performed and an EN-79222-D2002 was drafted. LCLS-II 2 K CBX FDR, Mar 9, 2017

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

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

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