1. SNS Cryoplant Commissioning Past Experiences
Dana Arenius
Workshop on Commissioning of LCLS-II Cryoplant
4-5 December 2018
Contracted by:
DOE DE-AC05-00OR22725

2. SNS Cryoplant Overview
Outline
SNS Cryoplant Overview
Why compare LCLS-II to SNS
Major Components/Subsystems
Commissioning Sequence
Commissioning Results and Problems
SNS/JLab Roles and Responsibilities
Lessons Learned
Commissioning Follow Up
Summary
Workshop on Commissioning of LCLS-II Cryoplant

3. SNS Cryoplant Overview
Workshop on Commissioning of LCLS-II Cryoplant

4. SNS to LCLS-II Comparison
SNS ~¼ 2.1K) of both LCLS-II plants but……
Had all of the required supportive utilities subsystems inclusive of major refrigeration components as LCLS-II
4.5K cold box
2K cold box
Helium gas storage tanks
LN2 dewar
Main warm helium compressors
Gas management rack
Helium dewar, 7kL
Purifier
He recovery compressors
Guard vacuum skid
MCC
PLC controls and hardware, control monitoring room
Oil Processor (added after commissioning)
Workshop on Commissioning of LCLS-II Cryoplant

5. SNS Major System Components (1)
Helium Compressors, Qty 6
4K Cold Box
LN2 Storage Dewar
4160V Motor Controllers
Oil Removal Vessels
Gas Storage Vessels, Qty 6

6. SNS Major System Components (2)
He Purifier
Gas Management
Guard Vacuum

7. SNS Major System Components (3)
4.5K Cold Box Delivery
4.5K Cold Box Top Plate

8. SNS Major System Components (4)
7kL Helium Dewar
Instrument Air System
He Recovery Compressors

9. SNS Major System Components (5)

10. SNS Major System Components (6)
Control Monitoring Room

11. Commissioning Sequence
Outlined as published in “Advances in Cryogenic Engineering”, Cryogenic Engineering Conference- CEC, Volume 51B, Pages
Commissioning of safety systems (ODH, Fire Protection)
Verification of Plant Installation ( Equipment setting, Electrical, Mechanical), installation contractor representatives on hand
LN2/Helium Gas Availability
Commissioning and Performance of Plant Utilities (Electrical, Instrument Air, Cooling Water, UPS, Emergency Generator)
Readiness to operate check (training, staffing, procedures, safety training)
Pre-commissioning Activities
Instrument/valve calibrations and with functional checks to control system
Charcoal filter and absorber bed loading and decontamination
Evacuation/purification of helium storage tanks, LN2 dewars, process piping, oil removal, compressor skids, etc.
MCC safety programming, compressor drive motor bump and alignment checks
Warm helium compressor oil filling
Commissioning/Performance Tests
Warm Helium Compressor, Oil Removal, Gas Management (160 hour run test)
4.5K Cold Box, helium dewar, test heaters (per vendor specification test requirements)
Guard Vacuum System
2K Cold Box, distribution system (per vendor specification test requirements)
Workshop on Commissioning of LCLS-II Cryoplant

12. Commissioning Results (1)
Warm Helium Compressors, December 2003
6 compressors installed, 3 per 1st and 2nd stage
Only 2 compressors per stage required for operation
Passed 160 hour system performance and reliability test,
1,4,16.5 atm system 1149 g/sec flow rate
Commissioning problems encountered
Oil coolers
Oil cooler discharge temperatures were high
Temperature survey along oil cooler length indicated bypass flow around tube sheet separator within cooler
Cooler tube separator sheets were installed upside down
Vendor quickly repaired installation
Oil pump bypass control and relief valves
Thu leakage, vendor quick repair
Workshop on Commissioning of LCLS-II Cryoplant

13. Commissioning Results (2)
4.5K Cold Box, July 2004
Tested for liquefaction and refrigeration capacities
Passed liquefaction capacity at 80 g/s
Initially failed refrigeration capacity using vendor T-S cycle
JLab modified vendor T-S cycle to 2.8 from 4 atm to achieve refrigeration capacity by driving upper turbine refrigeration harder
LN2 consumption
Higher than expected LN2 consumption, 20% higher for liquefaction, 50% higher for refrigeration modes
Traced to upper cold box heat exchanger design
SNS working with vendor to optimize LN2 consumption
Workshop on Commissioning of LCLS-II Cryoplant

14. Commissioning Results (3)
2K Cold Box, July 2004
Successfully tested at 120 g/s, 2.1K
Limited amount of cryomodules existed in linac (5 of 23)
Problems encountered
Cold compressor electrical feed thru connectors found leaking process helium gas into cold box vacuum space
Connector manufacturer had “lost” the technology to fabricate leak tight connectors after company reorganization
JLab/SNS engineered/fabricated replacement electrical connectors until connector vendor replaced original supply (months later)
Low power factor experienced on drive motors, drive trips
Drive motor sizing much larger than necessary
Adjusted drive motor programming parameters to compensate
Workshop on Commissioning of LCLS-II Cryoplant

15. Commissioning Results (4)
Linac Distribution System, August 2004
Successfully commissioned with only 1 Medium Beta Cryomodule in linac
Both primary 4K and 35K shield supply and return
No problems encountered
Workshop on Commissioning of LCLS-II Cryoplant

16. Staffing Manpower
Workshop on Commissioning of LCLS-II Cryoplant

17. Pre-commission and Commissioning Staffing Plan
Fabio Casagrande (SNS group leader) provided an SNS staff commissioning plan >1 year prior to commissioning start, Sept 5, 2002
Staffing/Duration was based on work training experience at JLab
JLab participation was during major equipment commissioning and performance testing
Subsystems were turned over to SNS ownership when commissioning of each major subsystem was completed
JLab monitored and advised SNS pre-commissioning via computer link to JLab
Workshop on Commissioning of LCLS-II Cryoplant

18. Commissioning Integrated Schedule
We must test major components before warranties expire: Dec’03

19. Sequential pre-commissioning/commissioning planning is effective
Lessons Learned
Sequential pre-commissioning/commissioning planning is effective
Performance issues for “one of a kind” equipment are more likely to be encountered
Staffing plan should include engineering, technicians, operators vendors personnel to address and mitigate performance issues in a timely fashion. This includes electrical, mechanical, process design and controls.
Workshop on Commissioning of LCLS-II Cryoplant

20. Commissioning Follow Up
SNS has been successfully operating a reliable cryoplant for many years since 2004
After commissioning, a working agreement between JLab and SNS was established in support of the operation of the plant and the loan of spare part equipment
Workshop on Commissioning of LCLS-II Cryoplant

21. Summary
SNS cryogenic plant met the refrigeration and liquefaction capacities
Plant commissioning requires substantial pre-check and “make ready” activities from utility, training, procedures and supportive equipment
Issues were encountered with most all the major “one of a kind” systems which required co-operative analysis, mitigation and repair between laboratories and vendors to ensure timely resolution
SNS developed a manpower plan for their contribution to the major equipment pre-commission and commissioning activities
Plant and commissioning activities were a part of the SNS personnel training at JLab
Workshop on Commissioning of LCLS-II Cryoplant