MT/ MSR

Question 1

What is the purpose of the MSR’s?

Answer 1

Improve the quality of the high pressure turbine exhaust steam before it enters the LPT. Improves LPT efficiency. Aids in overall plant efficiency.

Question 2

How does the MSR improve the quality of the steam?

Answer 2

By mechanically removing moisture and reheating the dry steam by passing it across the reheater tube bundles.

Question 3

What is the purpose of the MT system?

Answer 3

• Convert thermal energy from SG’s to mechanical energy that is used to spin the MG.
• Provide extraction steam for FW heating to increase plant efficiency.
• Provide hot reheat steam for operation of MFWPT’s.

Question 4

Where does the the HPT provide extraction steam to?

Answer 4

3rd stage to 1st stage reheater MSR and 7 HP FW htr

5th stage to 6 HP FW htr

Question 5

Where does the LPT provide extraction steam to?

Answer 5

8th- #4 LP FW Htr
9th- #3 LP FW Htr
11th- #2 LP FW Htr
12th- #1 LP FW Htr

Question 6

What provides steam to the 2nd stage MSR reheater coils?

Answer 6

Main steam

Question 7

What does Gland seal do for the MT system?

Answer 7

Prevent steam leaking out

Prevent air leaking in

Question 8

What is the thrust bearing?

Answer 8

Located on the turbine shaft between HPT and 1st LPT. It supports axial thrust of rotors.

Question 9

How many journal bearings are there>

Answer 9

One located at each end of all turbines and MG. 10 total

Question 10

What does the MT Turning Gear do?

Answer 10

• Rotates shaft slowly and continually during shutdown periods when rotor temp changes occur
• To jack the rotor small amounts at desired intervals to facilitate inspection.
• Helps provide a more uniform and controlled starting sequence

Question 11

Describe the starting of the TG.

Answer 11

Piggyback motor mounted on top of TG.
Once Start is pressed the piggyback motor will start if;
- MG C/B’s or motor operated disconnect are/is open
- Bearing lift pump is running
- Bearing LO pressure is adequate
- TG is disengaged

Question 12

Where is the MT overspeed device located?

Answer 12

on the front standard of the main turbine

Question 13

How many speed sensors are there? What are they for?

Answer 13

5 for EHC speed control

1 for Turbine supervisory system

Question 14

What is the purpose of the MSR’s?

Answer 14

Designed to remove excess water, via moisture separators (chevron vanes), and raise steam temperature to super-heated steam

Question 15

What is the LPT side to side differential temperature maximum difference?

Answer 15

50 degrees F

Question 16

What are the CIV’s?

Answer 16

Combined intermediate valves (1-6)

Two valves in one valve body and share a common seat

Question 17

What do the CIV’s prevent against?

Answer 17

Overspeed condition caused by the cross around piping.

Question 18

What are the two valves called in a CIV?

Answer 18

Intercept Valve and Stop Valve

Question 19

What is the purpose of the stop valve?

Answer 19

Serve as a backup to the IV’s to isolate flow during a loss of load in the event of a failure of the IV.

Question 20

Which valves in the MT valves are controlling?

Answer 20

Intercept valves 1-3, Main Turbine Stop valve 2, and Control valves 1-4

Question 21

Which valve in the MT system are non-controlling?

Answer 21

Main turbine stop valves 1,3,4, Intercept valves 4-6, Intermediate stop valves 1-6.

Question 22

Explain the relationship with the controlling and non-controlling valves in the MT system?

Answer 22

Controlling are considered master and non-controlling are considered slave. When a controlling valve goes closed to 50% the slave valve will trip closed. When a controlling valve opens to 90% the associated slave valve will open.

Question 23

After the piggyback motor for the MT TG is started; when will the TG engage?

Answer 23

• Rotor speed less then 2 RPM

- Low speed permissive from EHC system