U1 Main Turbine Cooling/SS/LO Flashcards
What are the U1 MT Hardwired Trips?
AMSAC
SI
Steam generator Level Hi-Hi 67%
Manual
Overall HEA
IOPS 110%
Stator Cooling Water (10 sec delay)
- Lo Press
- Lo Flow
- Hi Temp
Thrust Bearing position Abnormal ±39 mils
Unit HEA
Reactor Trip
Emergency Trip
What auto starts an AC Suction LO Pump on U1?
- Turbine Trip
- Low Suction Press < 10# from the Shaft Driven Oil Pump
- Turbine Trip
What auto starts a DC Emergency Bearing Oil Pump on U1?
- Turbine Trip
- Low discharge press < 125 psig from the Shaft Driven Oil Pump WITH Turning Gear oil pp discharge press < 10 psig
What auto starts the Turning Gear Oil pump and the DC Backup Oil Pump?
-Turbine Trip
- Bearing Header pressure < 15 psig
- Turbine Trip
When do the Bearing Lift Pumps auto start?
On Turbine Low Speed Switch only (Does NOT start on turbine trip)
When do Bearing Lift Pumps 2 and 4 start?
20 seconds after Turning Gear engagement to ensure sufficient drag on turbine shaft to prevent the Turning Gear from disengaging.
Which stop valve allows pre-heating of chest and shell (HPT)?
2 Stop Valve
When does the U1 Turning Gear auto engage?
When the turbine stops (< 1/2 rpm)
What is the turning gears purpose?
Prevents/removes turbine bow on the shaft
- Removes a temporary rotor bow during turbine warm up, before a turbine roll
Is there an auto trip on high vibrations for the Unit 1 Main Turbine
No
What is the purpose of the Main Turbine Thrust Bearing?
Limits axial movement of the turbine rotor to prevent stationary and rotating blade contact
What is the purpose of the Main Turbine Journal Bearing?
Support the weight of the turbine and generator rotors and restrict movement to the axial direction only
What supplies Main Turbine Steam seals when starting up?
50# Aux Steam
What supplies Main Turbine Steam seals during normal operation?
Leakage from exhaust of HPT and MFPTs
What are the EHC pump auto starts?
Auto 1 - 1450#
- if run pump goes to status other than run or test
- 3/3 EHC transmitters fail
- Auto 1 Test Signal
Auto 2 - 1375#
- Auto 1 Test Signal
What does SRA-1800 look for on U1?
Primary to secondary tube leak
What maintains the bearing oil header pressure for the U1 Main Turbine?
1-SV-248, Main Turbine Oil Turbine Driven Lube Oil Booster Pump Discharge Safety Valve, maintains it at 25#
What are the EHC loads?
- Main Feed Pumps
- Main Stop Valves
- Front Standard
- Main Control Valves
- Right Intermediate Valves
- Left Intermediate Valves
What are the Unit 1 Main Turbine Trips from PLC
- Low Condenser Vacuum
- Overspeed 107%
- Oil Press (Bearing)
- Lo EHC header Press
- Lo Trip Header Press
- Loss of both DCS Power Supplies
What are the 3 purposes of the Main Turbine and Control System?
- Convert Thermal Energy into mechanical energy
2.Control the flow of steam entering the main turbine under normal conditions
- Prevents steam from entering the main turbine in the event of emergency conditions
Immediately following a Unit 1 Main Turbine Trip, which Lube Oil System pumps are running?
- Turning Gear Oil Pump.
- AC Suction oil pump.
- DC Backup Oil Pump.
- DC Emergency Bearing Oil Pump.
U1 MT backup overspeed trip (IOPS) is what percent of rated speed?
110%
What is the purpose of mist eliminator in U1 MTLO system?
Remove oil vapor from the discharge flow of the vapor extractors. Water vapors can go out roof!
What is the purpose of the Intercept Valves?
Prevents overspeed on a turbine trip. The Reheat stop valve is a backup
With U1 Main Turbine / Generator paralleled to the grid, the Main Turbine begins to overspeed. A Turbine trip will occur when the PLC senses turbine speed at
107% speed on 2/3 speed sensors
What is the setpoint for the Low Bearing Oil Pressure on the Unit 1 Main Turbine?
Less than 8 psig for greater than 5 secs
What is the Low EHC Header Pressure Trip for the Unit 1 Main Turbine?
Less than 1100 psig
What is the Low Trip Header Pressure for the Unit 1 Main Turbine?
Less than 800 psig (2/3)
When will the loss of all 3 speed sensors trip the Main Turbine?
Only if the unit is NOT paralleled
What is the risk of operating without the MSRs in service?
Could result in water damage to the LP Turbine blades. Also results in lower efficiency.
What is the result of a loss of steam seal and packing exhaust?
Loss of the system results in steam leaking from turbine to atmosphere or air entering turbine casings.
LOSS OF VACUUM
What happens if the Steam Packing Exhauster trips?
Steam will come out!
How do 1-SRV-10 (Steam Seal Pegging Valve) and 1-SRV-11 behaved while coming up in power?
SRV-10 will throttle as necessary until about 50% power. SRV-11 will be closed.
What are the trips of the Unit 1 Main Turbine associated with SCW?
Low pressure at 36 psig
Low Flow at 499 gpm
High Temp at 81°C
What is the vacuum trip set point from PLC for the Unit 1 Main Turbine at 100% power?
22.5” Hg
