2 K Cold Box Process Vishy Ravindranath LCLSII
2 K Cold Box Process Vishy Ravindranath LCLS-II 2 K Cold Box FDR March 9, 2017
Outline 1. Background- 2 K Cold Box Design Changes 2. Impact of Design Changes on 2 K Process & Response (2 K Process Model) to 2 K Cold Box PDR Recommendation 3. 2 K Cold Box P&ID Overview LCLS-II 2 K CBX FDR, Mar 9, 2017 2
Introduction- First Light & Nominal Beam LCLS-II Linac Operation CRYOPLANT First Light Both Linac Strings supported by 1 Cryoplant Gradient - 14 MV/m 2 E 10 ≤ Qo ≤ 3 E 10 2 K Cold Box- “High. Flow” Configuration (Max. 2 K Mass Flow ~ 200 g/s) Nominal Beam Operations 2 Cryoplants, One cryoplant / LINAC String Gradient - 16 MV/m 2 E 10 ≤ Qo ≤ 3 E 10 2 K Cold Box- “Low. Flow” Configuration (Max. 2 K Mass Flow ~ 130 g/s) Interface Box Functionality: Connection of the Linac strings to a single cryoplant Connection of the upstream Linac to CP-1 and downstream Linac to CP-2 Independent cool-down & warm-up of each Linac String LCLS-II 2 K CBX FDR, Mar 9, 2017 3
2 K Cold Box Design Changes Since PDR (Sept-2016) Conflat Flanges and Removable Pipe Spool Design - PDR Current 2 K Cold Box Design- FDR Design Features 1. Design concerns High possibility of helium leaks associated with the large-10” flanges. 2. Schedule concerns – Leak testing and qualifying the flanges requires a minimum of 3 months of R&D. 3. Operation concerns. Switching between the High Flow and Low Flow configuration requires removal and reconnecting of large pipe spools in tight confined spaces 1. JLAB Designed U-Tubes (used in CHL-II plant) with Bayonet Connections used for connecting the 2 K return transfer line to the suction of CC 1 (high-flow) or suction of CC 2 (low-flow) 2. To bypass CC-6 (high – flow) and CC-1 (low-flow) requires removing the Utube external to the 2 K cold box. 3. Switching over from High. Flow to Low-Flow does not require working in confined spaces. 4
2 K Cold Box Process Model- PDR Recommendations Example: Upstream LINAC, E=16 Mv/m, Q 0 = 2. 7 x 1010 2 K Cold Box Process Model was reviewed during the PDR with the following additional action items Finding: “The 2 K cold box will not have a thermal shield. A heat leak analysis has not been performed for the device”. Comment: “Verify calculations to determine if heat leak into the first cold compressor justifies a shield. ” Recommendation: “Perform a heat leak analysis on the 2 K cold box to ensure that the inlet conditions to the 4. 5 K cold box can be met. ” LCLS-II 2 K CBX FDR, Mar 9, 2017 5
Response to PDR Comments/Recommendations Response A. The heat leak analysis was performed and documented in “LCLSII-4. 8 -EN-0804 LCLS-II 2 K Cold Box Process Analysis ” B. Thermal Shield is not incorporated for the following reasons: 1. The total heat leak into CC-1 suction line due to conduction and radiation heat load = 11 W 2. By adding a shield, the maximum heat load that can be eliminated is the radiation component ~ 8 W 3. CC 1 suction temperature increase due to the radiation heat load of 8 W = 0. 02 K 4. Reduction in the 2 K cooling capacity due to the 8 W of heat leak = 0. 6 % 5. The advantage of providing thermal shield is small 6. The design complication of incorporating thermal shield inside the 2 K cold box (constrained space) outweighs the small gain in the cooling capacity achieved by adding thermal shield. 6
Impact of U-Tubes on the Cold Compressor Suction Temperature and Pressure 9 -1/4” U-Tube Heat Load Component Heat Load includes 30% design margin [W] 0. 12 0. 1 Conductiona. Male Bayonet (QTY: 4) b. Female Bayonet (QTY: 4) 36 Radiation- Jacketed U-Tube 4 0. 04 40 0. 02 100 Total DT [K] Process Location Increase in CC-1 Suction Temperature. Additional Heat Load 0. 08 0. 06 120 140 160 180 200 220 Cold Compressor Mass Flow [g/s] Change in cold compressor suction conditions: 2. Maximum increase in suction pressure = 1 mbar LCLS-II 2 K CBX FDR, Mar 9, 2017 DP [mbar] 1. Maximum increase in suction temperature = 0. 1 K Increase in CC-1 Suction Pressure due to U-Tube 0. 8 0. 7 0. 6 0. 5 0. 4 0. 3 0. 2 0. 1 0 100 120 140 160 180 200 220 Cold Compressor Mass Flow [g/s]7
Impact of U-Tubes on the Cold Compressor Suction Temperature and Pressure ALAT was asked to check and provide maximum 2 K flow allowed for the revised inlet pressure and temperature conditions for the selected cold compressor wheel design. HIGHFLOW LOWFLOW LCLS-II 2 K CBX FDR, Mar 9, 2017 8
2 K Cold Compressor Vendor Calculation for the Revised Inlet Conditions Ref: ALAT’s Doc: C 4118 -NT-004 (2), “Mechanical & Electrical Design” Revised Cold Compressor Suction Conditions The selected cold compressor design can provide the following: 1. High Flow Configuration - Maximum of 204 g/s 2. Low Flow Configuration - Maximum of 130 g/s LCLS-II 2 K CBX FDR, Mar 9, 2017 9
Calculated 2 K Cold Box Suction Conditions for Required 2 K LINAC Operating Conditions a. For LINAC Operation, required 2 K cooling capacity (mass flow) to be provided by a single 2 K cold box ranges from: 100 g/s to 180 g/s. b. The LINAC 2 K Requirements are well within the 2 K Cold Compressor Capacity LCLS-II 2 K CBX PDR, Sept 27, 2016 10
2 K Cold Compressor Pump Down Ref: ALAT’s Doc: C 4118 -NT-004 (2), “Mechanical & Electrical Design” 2 K Pump Down Path –High Flow (CC 1 -CC 5) 2 K Pump Down Path –Low Flow (CC 2 -CC 6) LCLS-II 2 K CBX FDR, Mar 9, 2017 PDR Recommendation: “The pump down path being provided by the vendor is a different approach than Jlab, SNS, and FRIB are employing. Consider capturing this in a risk assessment and developing a back up plan in case commissioning proves difficult. ” Response: 1. ALAT has provided a proposed pump down path for the High-Flow and Low-Flow Configurations 2. JLAB will also provide a backup pump down plan based on CHL-II commissioning/operation experiences 11
2 K Cold Box P&ID To 4. 5 K CBX Clean up return 2. LHe Dewar 4. Safety Reliefs 3. CC Bypass Guard Vac. 3 atm He 1. 2 K RET From LINAC CM Inst. Air Cooling water 12
Interfaces –Bayonet Connections Int No. Interface Bayonet Size Component Pressure Rating [psig] Operating Temperature He-501 2 K return from Interface Box to CC 1 suction 9 -1/4” 60. 4 4 -300 He-502 CC 1 discharge to CC 2 suction 9 -1/4” 60. 4 4 -300 He-503 2 K return from Interface Box to CC 2 suction 9 -1/4” 60. 4 4 -300 He-504 CC 5 Discharge 5 -3/16” 75. 1 4 -300 He-505 CC 6 Suction 5 -3/16” 75. 1 4 -300 He-506 CC 6 Bypass 5 -3/16” 75. 1 4 -300 He-507 30 K return from 2 K Cold Box to 4 K Cold Box 5 -3/16” 75. 1 4 -300 He-508 4 K vapor supply from LHe storage dewar to CC 1 suction 3 -1/8” 83. 2 4 -300 LCLS-II 2 K CBX FDR, Mar 9, 2017 13
Interfaces Int No. Interface He-510 Cleanup return He-511 Component Rating [psig] Operating Temperature [K] ½” pipe weld 150 300 3 Atm He supply 1” pipe weld 150 300 GV-512 Guard vacuum 1” pipe weld Vacuum-15 300 IA-513 Instrument air 1” pipe weld 150 300 He-515 Relief Valve Discharge Collector 3” pipe welded 15 4 -300 CW-517 Cooling water Supply 2” pipe weld 100 300 CW-518 Cooling water return 2” pipe weld 100 ~300 LCLS-II 2 K CBX FDR, Mar 9, 2017 Connection 14
2 K Cold Box Control Valves 2 K Cold Box consists of six cryogenic control valves: 1. PV 41212 (Cold Compressor Bypass Valve): Back-filling of LINAC and for bypassing the cold compressor during 4. 5 K Standby mode. 2. PV 41500/41510/41520 (4. 5 K supply from Dewar to 2 K Cold Box): to test the 2 K cold box/compressors 3. PV 41170 & PV 41160 (Cold Compressor Discharge valves) LCLS-II 2 K CBX FDR, Mar 9, 2017 15
2 K Cold Box Control Valves 1. Control Valves are sized in accordance with Flow Equations For Sizing Control Valves - ANSI/ISA-75. 01 (IEC 60534 -2 -1 Mod)-2007. 2. All valves are fail closed, equal percentage, range-ability of 1: 100, angle valve body pattern. 3. The detailed calculations are documented in : Ref: LCLSII-4. 8 -EN-0802 “LCLS-II Cryoplant Cryogenic Control Valves Sizing” 4. JLAB will procure the control valves and provide them to the 2 K cold box manufacturer LCLS-II 2 K CBX FDR, Mar 9, 2017 16
2 K Cold Box Venturi Flow-Meters Flows considered for the sizing are based on CHL-II 2 K Cold Compressor Flow Data 280 g/s 200 g/s The flowmeters are sized in accordance with : “Measurement of Fluid flow by means of pressure differential devices-Part 1: ISO 51671 (1991)”. The detailed calculations are documented in : “Ref: LCLSII-4. 8 -EN-0803 LCLS-II Cryoplant Flowmeter Sizing” JLAB will procure the Flow-Meters and provide them to the 2 K cold box manufacturer CC mass flow CC 5 Discharge Pressure = 1. 2 atm CC 5 Discharge Temperature 30 K 6 K 17
Utilities 1. Electricity: 480 VAC +/-24 V 3 phase – 60 Hz +/-1 Hz 2. Vacuum guard (For CC and bayonets) Vacuum will be used for the sealing intercept 3. Instrument air • For 6 pneumatic control valves • Supply pressure of 90 psig 4. Cooling water (For CC and Diffusion Pump) • Maximum inlet temperature : 38°C • Maximum return temperature : 49°C • Maximum flow rate per compressor : 0. 75 m 3/h (3. 3 gpm) • Pressure drop: < 1 bar PDR Recommendations: Consider the use of a closed loop water cooling for the turbine, cold compressors and diffusion pump. Response: There is a secondary closed water loop dedicated for the turbines, cold compressors and diffusion pumps in each cryoplant. P&ID: 79621 -0001, “LCLS-II Cooling Water System (For Turbines & Cold Compressors)” 18
Summary q The cold compressor design accommodates the anticipated variation in the heat load. q The design & interface requirements for the 2. 0 K Cold Box have been clearly identified on the P&ID. q PDR Review recommendations have been addressed with further heat load analysis as recommended q Detailed supporting calculation documents been developed: Document No. Title Author Status LCLSII-4. 8 -EN-0802 LCLS-II Cryoplant Cryogenic Control Valves Sizing V. Ravindranath Under Review LCLSII-4. 8 -EN-0803 LCLS-II Cryoplant Flowmeter Sizing V. Ravindranath Under Review LCLSII-4. 8 -EN-0804 LCLS-II 2 K Cold Box Process Analysis V. Ravindranath Released 79222 -0000 2 K Cold Box P&ID JLAB Released LCLS-II 2 K CBX FDR, Mar 9, 2017 19
Back-Up LCLS-II 2 K CBX FDR, Mar 9, 2017 20
LCLS-II Cryomodule Heat Load at 2. 0 K q q REF: (1) Tom’s Excel Spread Sheet: “LCLScryo. Heat-23 Feb 2016 -First. Light. xlsx” Tables show the “ 2. 0 K Heat Load” (does not include the heat load on Transfer Lines) The Static Heat Load includes a Design Margin of x 1. 30. The uncertainty in the Dynamic Heat Load is in terms of the Cavity Quality Factor A. First Light Configuration E = 14 MV/m, Qo = 2. 7 E 10 E = 14 MV/m, Qo = 2. 0 E 10 E = 14 MV/m, Qo = 3. 0 E 10 Up-stream Down-Stream Total Static [k. W] 0. 158 0. 186 0. 344 Dynamic [k. W] 1. 100 1. 200 2. 300 Total [k. W] 2. 644 1. 258 1. 386 Up-stream Down-Stream Total Up-stream Down-Stream 0. 158 0. 186 0. 344 0. 158 0. 186 1. 462 1. 608 3. 070 0. 968 1. 083 3. 414 1. 126 1. 620 1. 794 1. 269 Total 0. 344 2. 051 2. 395 B. Normal Beam Operation E = 16 MV/m, Qo = 2. 7 E 10 E = 16 MV/m, Qo = 2. 0 E 10 E = 16 MV/m, Qo = 3. 0 E 10 Up-stream Down-Stream Total Static [k. W] 0. 158 0. 186 0. 344 Dynamic [k. W] 1. 415 1. 615 3. 030 3. 374 Total [k. W] 1. 573 1. 801 Up-stream Down-Stream Total Up-stream Down-Stream 0. 158 0. 186 0. 344 0. 158 0. 186 1. 878 2. 146 4. 024 1. 261 1. 464 4. 368 2. 036 2. 332 1. 419 1. 650 Total 0. 344 2. 725 3. 069 E = 19 MV/m, Qo = 2. 0 E 10 E = 19 MV/m, Qo = 3. 0 E 10 Static [k. W] Dynamic [k. W] Total [k. W] Up-stream Down-Stream Total Up-stream Down-Stream 0. 158 0. 186 0. 344 0. 158 0. 186 2. 569 2. 987 5. 556 1. 717 2. 024 5. 900 2. 727 3. 173 1. 875 2. 210 21 Total 0. 344 3. 741 4. 085
Heat Load on the Transfer Lines- Cryomodule, CDS & Cryoplant Heat Load on the Transfer Lines Upstream Line A: 89 W Line B: 261 W Downstream Line A: 54 W Line B: 233 W Heat Load includes a design margin of x 1. 3. Ref: LCLSII-4. 8 -EN 0804 LCLS-II 2 K Cold Box Process Analysis 22
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