Unit 1 Main Turbine and Controls Flashcards
Describe the steam flow paths through the U1 main turbine.
Main steam header - 4 parallel stop valves - 4 parallel control valves - 4 steam leads - High pressure turbine - 2 MSR’s - 6 crossover lines - 6 combined intermediate valves (intercept valve, intermediate stop valve) - 3 low pressure turbines - 3 main condensers.
Describe the flow paths in the U1 main turbine and control hydraulic fluid system.
Pumps take suction from tank and discharges through the distribution block, in the distribution block the flow path is past the individual relief valves, then through the isolation valves, and discharge check valves then through the filter selector valve. Then the fluid exits the block and passes through the discharge filters.
How is the U1 main turbine affected by the loss of NESW?
It provides cooling for the lube oil used for the turbine bearings, loss of NESW would result in overheating and possible failure of the bearing lubricating system.
What is the purpose of the main turbine?
Converts the thermal energy of the steam flowing through the turbine into mechanical energy for turning the main generator.
What is the purpose of the EHC system?
Provides the pressure needed to position the turbine steam control and isolation valves.
What are the parameters for generator seal oil?
Balanced within 2 psig from one end to the other.
5-6 psig greater than Machine gas pressure.
What do journal bearings do?
Provide support with minimum friction for the turbine shaft/rotors and maintain their radial position in the turbine casing.
What do Thrust bearings do?
Maintain axial position of the shaft/rotor in the turbine casing by accepting the axial forces transmitted to the shaft during turbine operation.
How do the high pressure turbine Stop and Control valves operate?
Hydraulic to open, Spring to close.
What does the turning gear do?
Slowly rotates the turbine shaft when turbine is shutdown to get circumferential uniform temperature distribution in rotors.
When should you have the turning gear in service?
When >_ 500*f
Or when steam seals are In service.
What is EHC temperature control based on?
The temperature of the EHC in the tank.
What is the purpose of the EHC accumulators?
Gives a reserve source of fluid during transient conditions.
