MT/MSR: Main Turbine and Moisture Separator Reheaters Flashcards Preview

LOIT Systems 2018 > MT/MSR: Main Turbine and Moisture Separator Reheaters > Flashcards

Flashcards in MT/MSR: Main Turbine and Moisture Separator Reheaters Deck (78)
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Which Main Stop Valve has an internal bypass? Why?

MSV #2

To pressurize the below seat area on all Main Stop Valves allowing them to open.


What is the RPM limit on the Main Turbine before vacuum can be broken?

1200 RPM


What is required to place Steam Blanketing in service?

Main Condenser vacuum


How does the Reheat Steam Low Load Valve (RSLLV) control 2nd Stage Reheat Steam pressure?

- Linearly with load from 15% to 65% - compares cross-around pressure to 2nd stage pressure


When does the local pushbutton for the Main Turbine Turning Gear work?

When the Control Room Switch for the TG must be in STOP or PULL-TO-LOCK. Cannot be in START or AUTO.


Describe how the Control Intercept Valves are constructed.

They of a stop valve and an intercept valve that share the same seat. The stop valve backs up the intercept valve.


What is the basis for the MSR reliefs?

Protection in the event the Combined Intermediate Valves shut and the Control Valves do not.


What is the setpoint for the High Exhaust Hood Temperature Trip of the Main Turbine?

225 F


What is bad about extended operation below 5% or the excessive use of Exhaust Hood Spray?

Last Stage Bucket Erosion


Why do the High Level Control Valves for the 1st and 2nd Stage stay open while at low powers? 

To provide a constant vent to the 1st and 2nd stage tube bundles for the MSRs to the Main Condenser while coming up in power. 1st stage closes at 10% and 2nd stage closes at 20%


What kind of warming must be done to the MSRs prior to admitting reheating steam? Why?

At least 15% for 12 hours

Avoids thermal cycling 



What does a Thrust bearing do?

Protects against axial thrust


Is the Master/Slave relationship applicable in the test mode?



What does a Journal Bearing do?

Rotary protection


What is differential expansion in regards to the Main Turbine?

Thermal expansion at different rates between the stationary and non-stationary parts of the turbine.


What is [Air] Purging in regards to the ED System? When is it performed?

A scavenging path aligned to the Main Condenser through vents on the 1st and 2nd Stage MSR Drain Tanks that pulls all the contents of the MSR tubes (be it steam, air, or non-condensibles) into the Main Condenser.

Performed just prior to admitting steam.


From where can you disarm a High Vibration Trip of the Main Turbine?

From the Turbine Supervisory Cabinet


Where are the Main Turbine Journal Bearings?

At the end of each turbine and generator


Why were CIVs #1, #2, #3 chosen as the Masters?

Rotor balancing concerns if one master were to fail


What is the setpoint for the Backup Overspeed Trip of the Main Turbine?



What are the Controlling Steam Valves associated with the Main Turbine?

Main Stop Valve #2

Control Valves #1, #2, #3, #4

Control Intercept Valves #1, #2, #3


How are the MSR Relief valves distributed?

2 on A 1 on B 2 on C 1 on D


What is the setpoint for the Excessive Vibration Trip of the Main Turbine?

12 mils


To where do the 2nd Stage MSR tubes drain?

To the 2nd Stage MSR Drain Tank and then to the #7 HPFWH or the Main Condenser


What provides 1st Stage Reheat Steam for the MSRs?

3rd Stage Extraction Steam


How does the High Level Control Valve for the MSR Drain Tank behave while <10% power?

It its failed open as long as the Steam Blanketing Mode Selector Switch (MTN-HS-519) is in AUTO


How does the overspeed device work for the Main Turbine?

An unbalanced ring

centrifugal force puts the ring in an eccentric postion to strike a trip finger


What do you do if a tube breaks in the 2st Stage of an MSR?

Isolate the 2nd Stage Reheat steam to the MSRs.


What is unique about the Turning Gear motor for the Main Turbine?

It has a 'piggyback' motor.

Used to get the TG started so it can engage. Once engaged, #5 and #8 (bearings 7 and 10) oil lift pumps stop and the piggyback motor stops 10 seconds later. 


What is the Turning Gear used for on the Main Turbine?

To rotate the shaft to prevent distortion on a cooldown

Jack the rotor for inspection

Rotor breakaway on Main Turbine startup