LOVEJOY CONTROLS SUPPORTED FEEDPUMP TURBINE MAINTENANCE

Scheduling Feed Pump Turbine Outage Maintenance Planned nuclear refueling and fossil boiler outage durations have been cut dramatically in the past twenty years. While in the 1980's it was not uncommon for a nuclear plant to spend eight or more weeks of equipment maintenance during a refueling outage, today this outage is scheduled to be less than 30-days. Unfortunately, the equipment to maintain has not changed much with the shrinking work time. As a consequence, a lot of routine outage work on feed pump turbines is now either bypassed or scheduled out on ten or more year intervals. The startups after the truncated maintenance outages become much more unpredictable and susceptible to feed pump turbine trouble, which have on dozens of occasions the past several years cost plants millions of dollars in lost generation revenue. The startup phase is a terrible time to repair feed pump hydraulic systems since the plant is in need of the pumps for load escalation and the remaining obstacles to reach full load are dwindling, yet many hydraulic repairs require multiple time consuming oil system shut downs and equipment tag outs.

There is a way to restore reliability to the feed pump turbines without implementing long and tedious task lists. LCC would like to assist in this effort by rearranging the outage work plan to include a handful of key performance tests immediately following feed pump turbine shutdown which identify true problem areas requiring work and separating these from other tasks which need not burden the outage schedule because the affected components test out good to go. The concept is to perform initial quick dynamic tests while the oil system remains in operation, then to assign the specific tasks needed for each turbine. This method applies to all turbine hydraulics, speed control systems, valve operators, lube oil system, and supervisory instruments. By intelligently identifying components that actually need disassembly and inspection the task list is greatly reduced permitting successful execution within the truncated schedule time yet the headaches of emergency startup repairs are avoided.

LCC can assist you in defining the tests and the outcome interpretations for your next outage. The PM Task Lists which follow are geared to utilize shutdown performance testing whenever possible for early outage work definition and elimination of startup delays. Review the list for your feed pump turbines and contact us to work out a specific plan.

The LCC Controls System Factory Maintenance Service provides preventative maintenance packages which include all parts and technical direction ON SITE for quick and professional rebuilds of system components to optimum service condition. These rebuilds are periodically required for continuing trouble-free operation and are more involved than routine calibrations and checkouts.

When LCC is contracted to perform the maintenance packages, the following are provided at fixed pre-quoted cost:

Some system subcomponents and renewal parts have become difficult to obtain, especially on short notice. Don't be stuck in a start up scenario lacking what you need to restore operability on site.

Review the service task list needed for your next outage and contact LCC to schedule the required parts and technical direction.

Component PM Task Listing:

•  JUMP to     LCC SUPPORT HYDRAULICS MAINTENANCE TASKS - ALL SERIES CONTROLS 
•  JUMP to     LCC 200-SERIES WITH MAGTON E/H CONVERTERS 
•  JUMP to     LCC 200-SERIES WITH BADGER PNEUMATIC SPEED CHANGERS 
•  JUMP to     LCC 200-SERIES & SERIES-2 WITH EXLAR ELECTRIC ACTUATORS 

A. LCC SUPPORT HYDRAULICS MAINTENANCE TASKS - ALL SERIES CONTROLS
These tasks involve required periodic maintenance on hydraulic components which affect the reliability of the speed control systems and therefore should be addressed at the recommended intervals. These items are applicable to all LCC and non-LCC speed controlled feed pump turbines.
PM-200A-1  Servomotor LeakageTests (LP and HP where applicable)
Parts Renewals:	Servomotor Pilot and Pilot Bushing.
Service Period:	Servomotors should be tested for excess leakage every two years. Pilot replacements are not necessary of tests determine leakage within guidelines. Excess leakage in servomotors results in valve position instability and poor turbine speed control.
Post-Rebuild:	Dynamic x-y plot (Snitch) testing of control oil pressure to stroke function and response at five percent intervals. Response lag, excess hysteresis, and non-linearity issues addressed.
No Action Risk:	Servomotor oscillations causing turbine speed hunting and excess bushing wear. Feedwater control instability and possible trips due to low or high feedwater levels.
PM-200A-2   Stop Valve Solenoid Operator Inspections/Renewals/Replacements
Parts Renewals:	Detent Snaps, O-rings, Spool, Spool Seals, Solenoids OR full unit replacements.
Service Period:	Solenoid Valves should be inspected every four years of operation. Full rebuilds of all active parts should be performed every eight years.
Inspection Points:	Key inspection items are detent hold forces, solenoid actuation forces, FME intrusion, and spool wear.
Post-Rebuild:	Solenoid actuation verifications, flow control verifications.
No Action Risk:	Failure to reset turbine.
PM-200A-3  Stop Valve Pilot Operator Inspections/Renewals/Replacements
Parts Renewals:	Pilots, seals, O-rings OR full unit replacements.
Service Period:	Pilot Operated Valves should be inspected every four years of operation. Full rebuilds of all active parts should be performed every eight years.
Inspection Points:	Key inspection items are FME intrusion and spool wear.
Post-Rebuild:	Pilot actuation verifications, flow control verifications.
No Action Risk:	Failure to operate stop valve.
PM-200A-4  Autostop Oil Pressure Decay Test
Parts Renewals:	Determined by test.
Service Period:	EACH major outage.
Inspection Points:	Temporary instrumentation installed to observe autostop oil system during header pressure bleed down. Identifies non-conforming components requiring service
No Action Risk:	False turbine trips, difficult to diagnose.
Note: This test should be performed following shutdown at the start of the outage to identify exact components work required.
PM-200A-5  Control Pipe and Oil Tube Flush
Parts Renewals:	None
Service Period:	Elevated temperature high-flow oil flushes are recommended to remove tubing deposits each ten years. Failure to remove deposits can result in accumulation of FME and contamination of control components.
Inspection Points:	Pipe and tube swabs, flush discharge sock examination.
Post-Rebuild:	Leak test
No Action Risk:	Control component contaminations. Possible feedwater oscillations and turbine trips.
PM-200A-6  Bearing Drain Pipe Renewal
Parts Renewals:	Bearing drain pipe flange gaskets, re-insulation
Service Period:	Ten years with low lube oil water content, five years with high.
Inspection Points:	Internal pipe corrosion levels.
No Action Risk:	Control component contaminations. Possible feedwater oscillations and turbine trips.
Note: Removal and off site pickling and coating process arranged for three-day turn around at outage start.
PM-200A-7  Bearing Oil Orifice and Relief Valve Adjustment
Parts Renewals:	None
Service Period:	Each Outage
Inspection Points:	Relief Valve within Oil Reservoir
No Action Risk:	Incorrect oil balance, HP vs. Bearing Oil, possible low bearing oil trip, servomotor transient oil starvation.
Note: This is recommended as a post-shutdown, start of outage task.
PM-200A-8  Thrust Bearing Cage Oil Retention Test
Parts Renewals:	Possible orifice change
Service Period:	Each Outage
Inspection Points:	Thrust Bearing Cage
No Action Risk:	Thrust bearing damage and turbine trip.
Note: This is recommended as a post-shutdown, start of outage task.
PM-200A-9  Vapor Extractor Butterfly Valve Test/Adjustment
Parts Renewals:	None
Service Period:	Each Outage
Inspection Points:	Reservoir Vacuum
No Action Risk:	Water entry into oil system, corrosion contamination, feedwater oscillations and turbine trip.
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B. LCC 200-SERIES WITH MAGTON E/H CONVERTERS
PM-200B-1  LPEHC E/H Converters
Parts Renewals:	Cup Valve, Cup Valve Seat, Valve Stem, Pivot Shoulder Screws, Linear Bearing, Diaphragm.
Service Period:	E-H Converters should be fully inspected every two years of operation. Full rebuilds of all active parts should be performed every six years.
Post-Rebuild:	Dynamic x-y plot (Snitch) testing of control oil pressure to stroke function and response at five percent intervals. Response lag, excess hysteresis, and non-linearity issues addressed.
No Action Risk:	Servomotor oscillations causing turbine speed hunting and excess bushing wear. Feedwater control instability and possible trips due to low or high feedwater levels.
PM-200B-2   Flowpath Selection Valve Inspections, Testing
Parts Renewals:	Detent Snaps, O-rings, Spool, Spool Seals, Solenoids OR full unit replacements.
Service Period:	Flowpath Selection Valves should be inspected every four years of operation. Full rebuilds of all active parts should be performed every eight years.
Inspection Points:	Key inspection items are detent hold forces, solenoid actuation forces, FME intrusion, and spool wear.
Post-Rebuild:	Solenoid actuation verifications, flowpath verifications.
No Action Risk:	Flowpath mixing, possible inability to change flowpaths.
PM-200B-3  Electrolytic Capacitor Review/Replacement
Parts Renewals:	Electrolytic capacitors of control modules and isolators. Full power supply replacements.
Service Period:	Electrolytic capacitor components should be replaced every ten to twelve years of service.
Inspection Points:	Engineering review of component schematics produces capacitor change checklist.
Post-Rebuild:	Power supply calibration and general electronics functional test.
No Action Risk:	Component electrical failure, turbine shutdown.
PM-200B-4  Speed Probe Alignment Inspection
Parts Renewals:	None
Service Period:	Speed probe alignment to the target wheel should be verified following each major maintenance inspection or thrust bearing adjustment. Failure to align speed probes can result in speed channel losses and control upsets.
Post Adjust:	Speed Channel integrity verification.
No Action Risk:	Speed Channel Malfunctions, potential loss of speed feedback control.
PM-200B-5  Field Connector Inspections
Parts Renewals:	None
Service Period:	Depending upon conditions of service this should be performed every five to eight years on each system connector in the Signal Processor, Startup Station, and the Local Electronics Cabinets.
Inspection Points:	All multi-conductor connectors benefit from solvent cleaning and Stabilant 22 contact enhancer treatment.
No Action Risk:	Speed control loss, turbine shutdown.
PM-200B-6  Cabinet Ground Integrity Inspection
Parts Renewals:	Grounding Straps, Cables
Service Period:	Following any change in plant electrical ground status in the cabinet vicinity or every ten years as a general test.
Inspection Points:	Grounds are electronically measured and verified periodically to insure no loose connections or ground path impedance has been introduced.
No Action Risk:	Turbine speed transients with potential feedwater level trip. Difficult to diagnose.
Notes: Field cabinet grounds are essential to the defense against EMI/RFI intrusion and control upset.
PM-200B-7  Hydraulic Transformer Inspection (Applicable units only)
Parts Renewals:	Cup Valve, Cup Valve Seat, Bellows.
Service Period:	Hydraulic Transformers should be fully inspected every two years of operation. Full rebuilds of all active parts should be performed every six years.
Inspection Points:	Key inspection items are Cup Valve edge upsets, Cup Valve seat scratches or dents, bellows leaks and alignment.
No Action Risk:	Instability in COP, valve control oscillations.
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C. LCC 200-SERIES WITH BADGER PNEUMATIC SPEED CHANGERS
PM-200C-1  Factory Badger Positioner Rebuilds
Parts Renewals:	Diaphragms, bearings, gaskets, o-rings, shafts, springs if needed.
Service Period:	Full rebuilds should be performed each plant cycle. Badger valve inventory should be maintained to permit change outs each outage.
Inspection Points:	Wear on shaft and bearings, Springs, all internal pieces.
Post-Rebuild:	Post-Rebuild: Dynamic x-y plot (Snitch) testing of demand to control oil pressure function and response at five percent intervals. Response lag, excess hysteresis, and non-linearity issues addressed.
No Action Risk:	Instability in COP, turbine speed control hunting, possible feedwater level trip if in service.
Notes: Recommended Pneumatic actuator and Hydraulic base servicing in tandem.
PM-200C-2   Flowpath Selection Valve Inspections, Testing
Parts Renewals:	Detent Snaps, O-rings, Spool, Spool Seals, Solenoids OR full unit replacements.
Service Period:	Flowpath Selection Valves should be inspected every four years of operation. Full rebuilds of all active parts should be performed every eight years.
Inspection Points:	Key inspection items are detent hold forces, solenoid actuation forces, FME intrusion, and spool wear.
Post-Rebuild:	Solenoid actuation verifications, flowpath verifications.
No Action Risk:	Flowpath mixing, possible inability to change flowpaths.
PM-200C-3  Electrolytic Capacitor Review/Replacement
Parts Renewals:	Electrolytic capacitors of control modules and isolators. Full power supply replacements.
Service Period:	Electrolytic capacitor components should be replaced every ten to twelve years of service.
Inspection Points:	Engineering review of component schematics produces capacitor change checklist.
Post-Rebuild:	Power supply calibration and general electronics functional test.
No Action Risk:	Component electrical failure, turbine shutdown.
PM-200C-4  Speed Probe Alignment Inspection
Parts Renewals:	None
Service Period:	Speed probe alignment to the target wheel should be verified following each major maintenance inspection or thrust bearing adjustment. Failure to align speed probes can result in speed channel losses and control upsets.
Post Adjust:	Speed Channel integrity verification.
No Action Risk:	Speed Channel Malfunctions, potential loss of speed feedback control.
PM-200C-5  Field Connector Inspections
Parts Renewals:	None
Service Period:	Depending upon conditions of service this should be performed every five to eight years on each system connector in the Signal Processor, Startup Station, and the Local Electronics Cabinets.
Inspection Points:	All multi-conductor connectors benefit from solvent cleaning and Stabilant 22 contact enhancer treatment.
No Action Risk:	Speed control loss, turbine shutdown.
PM-200C-6  Cabinet Ground Integrity Inspection
Parts Renewals:	Grounding Straps, Cables
Service Period:	Following any change in plant electrical ground status in the cabinet vicinity or every ten years as a general test.
Inspection Points:	Grounds are electronically measured and verified periodically to insure no loose connections or ground path impedance has been introduced.
No Action Risk:	Turbine speed transients with potential feedwater level trip. Difficult to diagnose.
Notes: Field cabinet grounds are essential to the defense against EMI/RFI intrusion and control upset.
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D. LCC 200-SERIES & SERIES-2 WITH EXLAR ELECTRIC ACTUATORS
PM-200D-1  Exlar Electric Actuator Inspection/Maintenance
Parts Renewals:	Viton seals.
Service Period:	Three years under normal operating conditions.
Inspection Points:	Re-grease, check seals, roller screw fit check.
Post-Rebuild:	Valve stroke tests.
No Action Risk:	Excess actuator friction and roller screw wear.
PM-200D-2   Flowpath Selection Valve Inspections, Testing
Parts Renewals:	Detent Snaps, O-rings, Spool, Spool Seals, Solenoids OR full unit replacements.
Service Period:	Flowpath Selection Valves should be inspected every four years of operation. Full rebuilds of all active parts should be performed every eight years.
Inspection Points:	Key inspection items are detent hold forces, solenoid actuation forces, FME intrusion, and spool wear.
Post-Rebuild:	Solenoid actuation verifications, flowpath verifications.
No Action Risk:	Flowpath mixing, possible inability to change flowpaths.
PM-200D-3  Electrolytic Capacitor Review/Replacement
Parts Renewals:	Electrolytic capacitors of control modules and isolators. Full power supply replacements.
Service Period:	Electrolytic capacitor components should be replaced every ten to twelve years of service.
Inspection Points:	Engineering review of component schematics produces capacitor change checklist.
Post-Rebuild:	Power supply calibration and general electronics functional test.
No Action Risk:	Component electrical failure, turbine shutdown.
PM-200D-4  Speed Probe Alignment Inspection
Parts Renewals:	None
Service Period:	Speed probe alignment to the target wheel should be verified following each major maintenance inspection or thrust bearing adjustment. Failure to align speed probes can result in speed channel losses and control upsets.
Post Adjust:	Speed Channel integrity verification.
No Action Risk:	Speed Channel Malfunctions, potential loss of speed feedback control.
PM-200D-5  Field Connector Inspections
Parts Renewals:	None
Service Period:	Depending upon conditions of service this should be performed every five to eight years on each system connector in the Signal Processor, Startup Station, and the Local Electronics Cabinets.
Inspection Points:	All multi-conductor connectors benefit from solvent cleaning and Stabilant 22 contact enhancer treatment.
No Action Risk:	Speed control loss, turbine shutdown.
PM-200D-6  Cabinet Ground Integrity Inspection
Parts Renewals:	Grounding Straps, Cables
Service Period:	Following any change in plant electrical ground status in the cabinet vicinity or every ten years as a general test.
Inspection Points:	Grounds are electronically measured and verified periodically to insure no loose connections or ground path impedance has been introduced.
No Action Risk:	Turbine speed transients with potential feedwater level trip. Difficult to diagnose.
Notes: Field cabinet grounds are essential to the defense against EMI/RFI intrusion and control upset.