Control Oil Flashcards
What provides cooling water for the control oil hydraulic coolers?
Turbine cooling
What is the purpose of the control oil system?
Provides pressurized hydraulic fluid for the operation of: Main steam CVs Maintain steam SVs CIVs EHC system
What is the power supply for the main hydraulic pump motors?
NG
What is the power supply for the filter pump motor, fans and heaters?
NH
What provides power to the EHC control cabinet?
NN
What happens to the TC control valves upon loss of IA.
They fail open to the hydraulic oil coolers
The NLO will have to throttle open the bypass around the temp CV and then isolate the CV.
What happens to the hydraulic fluid is lost to the CO system?
The turbine will trip
What is used to maintain the hydraulic fluid above 85*F?
Two electric heater-fan units.
Automatically operated
How is hydraulic fluid maintained at or below 115*F?
The position of the hydraulic fluid coolers cooling water inlet valves is controlled.
What pressure is hydraulic fluid provided at?
1600 psig
How many hydraulic pumps are there and how many are normally operating?
There are two pumps with one normally in service.
Pump stroke varies to accommodate for pressure demand.
What provides cooling and lubrication to the main oil pumps?
There is an auxiliary pump attached to the main pump shaft via chain and sprocket.
At what control oil pressure does the standby pump start?
1300 psig
Where are the main control oil pumps normally operated from?
Control room.
Where are the control oil pumps located?
100’ turbine building
How are the four control oil accumulators arranged?
In parallel with a common discharge header.
What pressure is the accumulator precharged to with nitrogen?
1000 psig
What amount of reserve do the accumulators provide?
200%
How many hydraulic fluid coolers are there?
2-100% capacity
In parallel.
One in service one in standby
Where are the hydraulic coolers located in the system flow path?
Control oil return line en route to the hydraulic fluid reservoir
What cools the hydraulic fluid?
Shell and tube HX
Cooled by TC
What removes moisture in the hydraulic fluid reservoir?
Activated alumina
What color does the moisture absorbing alumina change to when it is exhausted?
Light pink.
Starts out blue
Describe the transfer filter pump
Rotary positive displacement.
What provide filtering for the hydraulic control oil when the hydraulic fluid pumps are shutdown?
Fuller earth filters.
How is the hydraulic fluid filtering pump operated?
From a local panel START/STOP
What is the purpose of the fuller earth filters?
Maintains the oil at a neutral pH and removes chlorine.
What prevents the fuller earth filters from over pressurization?
A relief valve set at 75 psig.
How does the stealth EHC system function?
It pumps in clean dry air to exclude contaminants and moisture.
What is the purpose of the transfer pump filter?
Filter the hydraulic fluid while the reservoir is being filled or drained.
Also used under power for continuous filtering.
The transfer filter is after the earth filter to remove any fines that may have loosened.
What is the purpose of the control oil recirc tank?
Downstream of the transfer filter for batch mode purification.
Used during caking
What are the four flow path options for valve CO-V204 Transfer and filtering selector valve?
Closed
Discharge
Recirc to fluid reservoir
Discharge to recirc tank.
At what pressure does the control oil standby pump auto start?
1300psig
How are the hydraulic fluid pumps tested?
HV29 is operated to relieve system pressure.
Auto starts the standby pump.
What happens if the control oil pressure drops to 1100 psig?
Alarm in control room and turbine trip
What amount of flow is continuously recirculated through the fuller earth filters?
Five percent
How would a loss of air effect the EHC fluid reservoir temperature control valves?
They would fail open
What would happen to the stealth EHC system on loss of IA?
It would lose its supply air.
