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An Overview of the Reliability and the Fault Trends of the SRS. Cheryl Hodgkinson Daresbury Laboratory Synchrotron Radiation Department. Contents. Introduction SRS Operational Statistics Analysis of the Operational Data Efficiency Fault Statistics Ageing and Obsolete Equipment - PowerPoint PPT Presentation
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WAO, Trieste, 24th - 28th September 2007
An Overview of the Reliability and the Fault Trends of the
SRS
Cheryl HodgkinsonDaresbury Laboratory
Synchrotron Radiation Department
WAO, Trieste, 24th - 28th September 2007
Contents• Introduction• SRS Operational Statistics• Analysis of the Operational Data
– Efficiency– Fault Statistics– Ageing and Obsolete Equipment
• Maintaining Reliability– Capital Investment and Redundancy– Risk Analysis– Post Incident Investigation and Modifications– Preventative Maintenance and Scheduling
• Conclusions and Acknowledgments
WAO, Trieste, 24th - 28th September 2007
Introduction
• The Synchrotron Radiation Source– 2GeV, 2nd Generation Light Source– Constructed between 1975 and 1980– Began scheduled user operations in 1981– Some SRS systems, mainly injector
components were salvaged from a previous accelerator
– Operational user facility for 26 years and scheduled for closure December 2008
WAO, Trieste, 24th - 28th September 2007
1984 – 1992•A number of upgrades
•HBL•Undulator•SC Wavelength Shifters
•Erratic efficiency profile due to new systems
2001 -2007•Dominated by water – vacuum incidents
•01/02 (65%) SCW 9 Absorber•04/05 (85%) RF Cavity Window & Quadrupole Vessel Absorber•06/07 (78%) TVM 9
•Efficiency in 06/07 was also significantly effected by Linac RF and HT systems and Gun Cathode issues.•Periods between incidents in excess of 90%.
1993 - 2001Stable period of operationGradual increase in efficiency to figures in excess of 90%
SRS Reliability Data
WAO, Trieste, 24th - 28th September 2007
SRS Fault Statistics
Vacuum Incidents
WAO, Trieste, 24th - 28th September 2007
Vacuum Incidents• Usually an isolated single failure• Difficult to predict and prevent
– failed RGA head– Quadrupole absorber – failed flowmeter
• Common Theme?– SCW Absorber & TVM 9– Both very different failure mechanisms– Both historical – not needed in the
current SRS configuration
WAO, Trieste, 24th - 28th September 2007
SRS Fault Statistics
Beam Loss Cause UnknownRF Klystron PSURF SystemControls
WAO, Trieste, 24th - 28th September 2007
Ageing and Obsolete Equipment
• Early Equipment– Built in-house– Repairs in-situ (time)– Can be repaired
• Later Equipment– Plug-in– Replaced with a spare– Return to manufacturer for repair– Support issues
WAO, Trieste, 24th - 28th September 2007
Ageing and Obsolete Equipment
• Concern regarding condition of in vacuum water circuits– 17 year old
absorber removed from storage ring
– Area’s milled away to examine any wall thinning
RESULT
No evidence of wall thinning or erosion
WAO, Trieste, 24th - 28th September 2007
Ageing and Obsolete Equipment
• External water circuits– Elbows– Near feedthroughs– Potential for
vacuum incident during repair
– Potential to cause more serious failure
WAO, Trieste, 24th - 28th September 2007
Ageing Machine – It’s not just equipment!
• It’s about people too!– Loss of design and build knowledge, as staff retire
• Less documentation for older equipment, drawings, maintenance schedules, etc.
• Can’t teach 20 years design, build and operational knowledge.– Succession planning important– You only know what’s been missed when the fault occurs
• Lapses in maintenance schedules• Longer fault rectification
WAO, Trieste, 24th - 28th September 2007
Capital Investment and Redundancy
• Capital investment– Must be bid for against
other priority items– Only essential systems
and components which would significantly improve efficiency
• Spares– Hot
• Power Converters• Storage Ring Klystron
– Vacuum vessels
Old RF PSU
New Commercial Unit
WAO, Trieste, 24th - 28th September 2007
Risk Analysis
• Benefit difficult to assess– The biggest risk is the one you don’t know
about
• At top level– Difficult to compare risk and focus resource– How do you compare extremely reliable long
lead time items against components that fail frequently, but are a fast repair?
– Does highlight major issues• Linac Klystron
WAO, Trieste, 24th - 28th September 2007
Risk Analysis• Most beneficial at individual technical group level• Direct comparison can be made between
equipment and fault hours contributed• Led to successful modernisation in key area’s
based on safety and operational risk
Risk Exposure Location Equipment Likelihood of Failure
Impact
09/06 10/05 09/04 01/03
Resources man
weeks
Cost Comments
Temperature Interlock Panel 1 1 1 1 1
4
2
10
10
6
2
3
4
2
6
1
2
2
0 £0K Replaced Aug 04 and drawings updated
Septum Extraction 1 1 1 1 2 6 0 £0K Replaced Sept 04, drawing updated. Proven reliability.
Septum Injection 1 2 2 4 4 6 2 £0K Spares available, Drawing need updating
Kickers Extraction 1 1 1 2 6 6 0 £0K Replaced Oct 05, drawing updated. Proven reliability.
Booster Accelerator
Kickers Injection 1 2 2 4 4 6 2 £0K Spares available, Drawing need updating
WAO, Trieste, 24th - 28th September 2007
Post Incident Investigation
• Learning from incidents is important• Committee is always formed to recover
and also determine actions to prevent reoccurrence.
• Actions from recent faults– Modification to TVM cooling pipes– Revised interlock testing schedule– Test rig to test thermionic valves on-site
WAO, Trieste, 24th - 28th September 2007
Preventative Maintenance and
Scheduling
WAO, Trieste, 24th - 28th September 2007
Conclusions
• The SRS has provided reliable user operations for over 26 years
• Vacuum incidents are isolated incidents, which do not indicate any form of systematic failure which would limit the life of the SRS
• Only evidence of any systematic failure due to ageing is the failure of copper elbows on water circuits
• The high operating efficiency demanded by the light source community can be maintained on an ageing machine using a variety of techniques.
WAO, Trieste, 24th - 28th September 2007
Acknowledgments
• The author would like to thank– Previous SRS Operations Managers for
compiling these statistics– Current and past Operations Teams for
providing the data– Steve Griffiths of EE&PS for providing his
Groups Risk Analysis DataAnd Finally...........
Daresbury Staff past and present for their contributions to SRS Operations
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