CO- Control Oil Flashcards
What is the purpose of the CO system?
Provide pressurized hydraulic fluid for the operation of:
Main Steam Control Valves, Main Steam Stop Valves, Combine Intermediate Valves, and Electrohydraulic Control System
When is the CO Transfer Filtering Pump used?
When fluid in the reservoir is being filled or drained or for bypass filtering of reservoir fluid when the Hydraulic Pumps are shut down
What system provides cooling for the Control Oil Hydraulic coolers?
Turbine Cooling Water
What system powers the CO Main Hydraulic fluid pumps?
NG
What happens if power is lost to the CO Hydraulic Pumps?
Turbine will trip on low oil pressure
What in the CO system is powered from NH?
NH powers the CO filter pump motor, fans and heaters
hydraulic fluid pump motor space heaers
What does NN do for the CO system?
Provides power to the EHC control cabinet
How is the CO Hydraulic Oil Cooler affected by a loss of IA? Operator actions?
TC control valves will fail open to the Hydraulic Oil Coolers
Operator will have to throttle open the bypass around the temperature control valve and then isolate the control valve.
Also goes to the CO Reservoir dryer/conditioner
What is the capacity of the CO Hydraulic Fluid Reservoir?
800 gallons of EHC fluid
What maintains the temperature of the CO Reservoir and how is it controlled?
Two heater-fan units, operated automatically by a temperature controller in the power unit to maintain fluid at >85F
Why is the CO Reservoir also equipped with temperature controllers?
They control position of the Hydraulic Fluid Coolers Cooling Water Inlet Valves such that the hydraulic fluid entering the reservoir is ~115F
Concerning the CO Reservoir Heater/Fan controls, what happens when the switch is taken to START? What if it were taken to AUTO instead?
Fans will start, but the heaters will not energize regardless of Reservoir temperature
If temperature of hydraulic fluid is <85F, the fans will start and the heaters will energize
Fans and heaters will continue to operate until the temperature of the hydraulic fluid is above 85F, at which time the heaters will de-energize and the fans will continue to operate for ~10 minutes to cool the heaters
What is the capacity of the CO Main Hydraulic Pumps? Power source? How do the pumps respond to system demand changes?
100% capacity each
NG
The pump will vary its stroke to meet the flow demand and maintain constant pressure
The pump will stroke to zero delivery when dead headed
What is the purpose of the CO auxiliary pump mounted into the main pump housing? What are the three setpoints on each inlet strainer?
Takes suction on the control oil reservoir and supplies cooling and lubrication to the main pump
filter is clean, needs cleaning, bypassing
What is the normal system pressure maintained at by the CO main hydraulic pump? What would cause the standby CO Main Hydraulic pump to auto start?
1600 psig
If system pressure falls to 1300 psi
Where are the CO Main Hydraulic pumps normally operated from and where are they located?
Control room
100’ Turbine Building
How much nitrogen is charged into the CO Accumulators? Where are the accumulators located?
1000 psig
inside the control oil skid
What is the purpose of the CO Accumulators?
Provide an immediate 200% reserve of fluid for transient flow requirements
What is the capacity of the two CO Hydraulic fluid coolers and what cools them?
100% capacity each
Cooled by TC
To what temperature range does the CO Hydraulic Fluid cooler maintain the fluid at? What temperatures would sound an alarm in the Control Room?
110-125F, set to maintain 115F
High temp of 130f or low temp of 85F
What is the purpose of the Air Dryer? How does it perform this function?
Removes moisture from the air breathed by the Hydraulic Fluid Reservoir during power unit operation
Air passing through the dryer is treated by layers of activated alumina to remove any moisture
Before entering the reservoir, the air is filtered by a .5 micron automotive type disposable treated paper filter element
Regarding the CO air dryer, what color does the alumina turn when it has become saturated with moisture, requiring replacement?
Pink
What system assists with the motive force in the CO Air Dryer?
Instrument Air
What kind of pump is the CO Transfer Filter Pump? Where is it controlled from?
Hydraulically balanced cartridge type vane pump (fancy way of saying rotary positive displacement pump)
locally
How does the Transfer Filter Pump operate to move fluid?
Fluid is captured between “vanes” in a low pressure larger region of the pump casing and forced out at a higher pressure in a smaller region of the pump casing
What different uses do I have for the CO transfer filter pump?
Used to provide control oil flow through the Fuller Earth Filters for oil purification when the Hydraulic pumps are secured
Used periodically during power unit operation for bypass filtering of fluid in the reservoir or when adding/draining fluid to/from the reservoir
What is the purpose of the CO Fullers Earth Filters?
(extend the life of hydraulic components)
Maintain Control Oil close to neutral pH level by neutralizing acids and absorbing water
Maintain chlorine content within specifications
How do we prevent overpressurization of the CO Fullers Earth Filters?
System is equipped with relief valves set at 75 psig
One relief valve is located downstream of both the Hydraulic Fluid Filtering Pump and FCV-27 to ensure that overpressure protection is available regardless of the pumping source
When is the CO Fullers Earth Filtering system normally in service? What D/P between the inlet and outlet gauges requires the filters be replaced?
Continuous operation when the turbine is in service
30 psid
What is the purpose of the CO reservoir conditioner/dryer (stealth) EHC system?What two important tasks are accomplished by the low pressure air purge in the Stealth EHC system?
dry gas blanketing system that injects instrument air into the head space of the reservoir
It extracts moisture from the fluid while excluding other contaminants from getting into the system
What is the purpose of the CO Recirculating Tank?
5 gallon tank that serves as a vessel for batch mode purification independent of the rest of the system
Used during “caking” process after replacing Fuller Earth Filter elements, which allows the saturation of the filter media to ensure the media will fulfill its filtering function
What are the four possible configurations associated with the CO system transferring or filtering selection valve, CO-V204? Where in the system is this valve located?
Closed, Discharge, Recirculate to Fluid Reservoir, Discharge to Recirculating Tank
directly downstream of the fullers earth filters
Where can I test the auto start capability of the CO Main Hydraulic Fluid pumps?
Performed locally at the CO skid and is coordinated with the Control Room during system startup before the turbine is reset
At what CO system pressure will the Turbine trip at?
1100 psi (2 out of 3 logic)
How is the CO system affect by a loss of Instrument Air?
TC Temperature Control Valves to the hydraulic fluid coolers fail open, over cooling the fluid and causing the heaters and fans to turn on
Control Oil Reservoir Conditioner/Dryer would lose its air supply, allowing moisture into the system
EHC dryer would lose the required air supply
Where is all the Control Oil equipment located?
100’ turbine building
What level is the CO reservoir maintained at?
-2” to +2”
How is new fluid added to the CO reservoir?
flexible hose connects a 55 gallon drum of fluid to the CO hydraulic fluid filtering pump
fluid is heated with a wrap-around heater plugged into a socket prior to transferring into the system
What indications and alarms are provided on the CO reservoir?
lo and hi temp
level indication and high level alarm
lo-lo and hi-hi level
On the CO main hydraulic pump discharge line, where does the pressure relief valve route back to? What components are directly downstream of the these pumps?
the CO reservoir
5 micron filters and pressure differential switches
Describe the testing of the CO main hydraulic pumps auto-start feature.
imitates a low pressure situation and starts the standby pump
performed locally prior to resetting the turbine
What is the purpose of the CO hydraulic fluid coolers? What is there capacity and how many are normally in service?
to cool the CO fluid returning to the reservoir from the steam admission valves
100%
1 in-service, 1 in standby
After replacing the CO fullers earth filters, what must be done prior to returning to normal service and why?
they must be “caked” for two hours by recircing the fluid through the earth filters, transfer pump filter and recirc tank back to the filtering pump
to prevent migration of fullers earth particles into the main fluid system when returned to normal service
What is the purpose of the CO transfer pump filter? Where in the system is this filter located? When should the filter be replaced?
filters hydraulic fluid to a low particulate size
at the outlet of the fullers earth filters
when the inlet gauge reads 15 psig
What happens in the CO system on a loss of turbine cooling water?
no TC to the hydraulic fluid cooler would overheat the oil
What are the precautions of working with fyrquel EHC fluid?
don’t get it in/on you
wear PPE
consult SDS and CUP prior to working around this chemical
