MT Ctrls Flashcards
What is IOPS powered by?
CRIDS I, II, III
What does IOPS do?
- Backup Overspeed protection at 110% (Hardwire trip)
- Its energize to trip (2/3) passive probes
What is the DCS power supply?
BOP Battery System (250 VDC) thru inverter
- BLC/CLC backup to inverters **
What is the DCS purpose?
Supply hydraulic fluid (motive force) for stop/control valve operation during normal and emergency conditions.
What does hood spray protect against?
Prevents LPT blade overheating
How fast do 10% and 20% manual runbacks go?
100 MW/min
When is a loss of a MFP runback enabled?
Unit 1 = 54.5%
Unit 2 = 60%
When a MFP is lost, how far do the main turbines runback?
Unit 1= 625 MW
Unit 2 = 752 MW
What will the Load Target be for an Over Power Delta Temperature and Over Temperature Delta Temperature Runback be?
- Target Load to 30 MW
When is power load unbalance armed?
Armed when 1st Stage Press > 40% (from DCS)
What is the Main Turbine Load Reference for a power load unbalance?
Load Ref to 30 MW Mw/min
What does the Droop Speed override signal do?
- Biases Load Ref signal which closes down on control valves and Intermediate Valves
- Protects from overspeed condition with output breaker closed
When is the Droop Speed override signal active?
> 1805 rpm
What is the primary tripping device of the Main Turbine?
- Trip Block Assembly
What is the one turbine trip input from TSI?
Thrust Bearing position
Will a failure of all 3 PLC speed sensors on the Turbine give you a turbine trip while on the grid?
NO!! Only if you’re NOT paralleled.
What is the load target for an ATWS runback?
1 MW
What is the purpose of Power Load Unbalance?
- Provides overspeed protection in the event of a large load rejection
- Used only on ATWS when the MT also fails to trip with manual AMSAC or Solenoid Trip
Which valves will reposition when resetting the Main Turbine?
The Reheat Valves open
What do the combined stop and intercept valves do for the turbine?
protect against overspeed of the turbine from residual steam from the MSRs on a turbine trip
If moving the turbine in MW Control IN, what happens?
Load reference will ramp toward the Load Target and the PLC sends a signal to the control valves to match Load Reference.
When in MW control IN, what happens when lake temperature moves around?
Valves will move around to maintain a constant MW value
When in MW control OUT, what happens when lake temperature moves around?
Valve position stays constant, but MWs will move around
What is unique to the Power Load Unbalance Runback?
Forced to MW OUT. All other Runbacks are forced to MW IN
What kind of probes does IOPS use?
passive probes
With regards to the solenoids for the Trip Block assembly, the MT will trip when how many solenoids do what?
2/3 de-energize
When an operator places MT DCS to MW IN, the values for the Load Target, Actual Load and Load Reference will go to what value?
the MW value of the Actual Load
The power load unbalance system is armbed above ____% and looks for a large rate of change in generator ____ per second
40% and amps
When is turbine warming required for Unit 1? And what is used?
Chest warming required < 460ºF
Shell warming required < 250ºF
Utilize SV2
