Control Oil Flashcards
Describe the basic flow path of CO.
Hydraulic fluid reservoirs => hydraulic fluid pump => hydraulic fluid filters => common header => accumulators! operating devices, servo valves, & trip devices => through one of 2 hydraulic fluid coolers
Some fluid goes over to the fuller earth filters and through the transfer pump filter before going straight back to the reservoir
What components are supplied by control oil?
Main steam stop & control valves
Main steam combined intermediate valves
EHC system
When is the transfer filtering pump used?
When filling the reservoir, draining the reservoir, for bypass filtering of the reservoir when the hydraulic pumps are shut down.
What cools the control oil hydraulic coolers?
TC
What are the power supplies to the main hydraulic pumps? The filter pump?
Filter pump - NH
Main hydraulic pumps - NG
What is the capacity of the fluid reservoir?
800 gallons
What temperature is the reservoir kept at or above?
85F
How is temperature controlled on the fluid coolers?
TC inlet valve is throttled to maintain 115F through the coolers.
What happens when the hydraulic fluid reservoir heater and fan control is placed in start?
Fans start, but heaters will not energize at all
What happens if the fans and heaters are in auto and hydraulic fluid temp goes above 85F?
Heaters de-energize and fans run for 10 more minutes to cool the heaters then shut off.
What is the purpose of the aux pump that is attached to the main hydraulic pump?
Take a suction on the hydraulic reservoir and supply cooling and lubrication to the main pump.
What will cause the standby control oil pump to auto start?
Low control oil pressure of 1300psig
What are the accumulators charged to?
1000 psig nitrogen to immediately provide a 200% reserve of fluid for transient flow requirements
Where does the high or low control oil temperature alarm sound?
In the control room
What color is good desiccant?
Blue
Where can you start the hydraulic fluid filtering pump from?
Locally at the pump
What do the Fullers Earth filters do?
Maintain close to neutral pH by neutralizing acids and absorbing water.
What does the Stealth EHC system do?
It’s a dry gas blanketing system.
It blankets the control oil reservoir headspace with super dry clean air. It simultaneously extracts moisture from the air while excluding contaminants from getting in.
How does the Stealth EHC work?
It uses a hollow fiber membrane to pass air through. It uses 5-20% of the rated air flow to transport the moisture from the module.
Where does the moisture laden air come out of the Stealth EHC?
Special ports located in the modules inlet end cap.
How is the membrane in the stealth EHC protected?
By incorporating a high efficiency coalescing pre filter into the system.
When is the transfer filter in service?
During reservoir filling and draining
What is the recirculating tank used for?
Used as a vessel for batch mode purification independent of the rest of the system.
What are the possible positions for the transfer and filtering system selector valve? (204)
Closed
Discharge (to oily waste)
Recirc to fluid reservoir
Discharge to recirc tank
How is the test function of the main hydraulic pumps performed?
The actuation of HV-29 manually relieves system pressure on an isolated supply header to test start the stby pump.
Test is performed locally at the skid.
What is the logic for the control oil pressure low alarms in the control room?
2/3 at 1100 psig
What happens to CO on a loss of IA?
Temperature control valves fail open and the stealth air dryer loses it’s air supply
What is the name of the EHC fluid and what are the handling precautions?
Fyrequel EHC
Causes illness if swallowed, skin and eye irritant.
