MAIN TURBINE AND AUXILIARIES

Question 1

What are the turbine trip conditions?

Answer 1

Rx Trip, both FWPs tripped, Loss of Stator Coolant (>9322 Amps for >3.5min or >25262 for >2min), Thrust Bearing ±30mils, EHC <1100#, Overspeed >108%, Electronic Overspeed >110% (2 of 3), Bearing Pressure <12# @ centerline, Low Vac (10 sec T.D. ), Moisture Sep hi-Hi (16 sec T.D. ), Gen bkr trip, Manual.

Question 2

What is the sequence for chest warming/pressure equalization using SV-2?

Answer 2

SV-2 internal, SV-2, other SVs together.

Question 3

How do Intermediate Stop Valves (CIVs) and Intercept Control Valves (IVs) operate?

Answer 3

CIVs OPEN/CLOSE together; IVs move as leader/follower (1/3/5 leaders open to 100% and close to 50% first).

Question 4

What is the function of journal bearings and thrust bearings?

Answer 4

Journal Bearings handle radial loads; Thrust Bearings handle axial loads.

Question 5

At what bearing vibration level should the turbine be tripped?

Answer 5

12 mils (MAP K-2-1).

Question 6

What is the turbine trip condition for low condenser vacuum?

Answer 6

Variable trip after 10 sec time delay when turbine speed >150rpm (MAP N-1-6).

Question 7

What action is required if stop valves don’t close on a turbine trip?

Answer 7

Put EHC-P-1A/B in PTL and OPEN EHC-V-FV-1 to remove hydraulic pressure.

Question 8

What are the sources of gland steam?

Answer 8

(1) Aux Steam, (2) Main Steam “B” OTSG at POAH, (3) Self-supplying HP Turbine Leakoff at >25% Power.

Question 9

What happens if gland steam condenser vacuum is too low or too high?

Answer 9

Too Low Vac = Steam coming out of seals; Too High Vac = Whistling sounds.

Question 10

What is the source of hood spray, and when should it not be used?

Answer 10

Source: CO-P-2 suction line via CO-V-227. Do NOT use hood spray <145°F to reduce last stage LP blade erosion.

Question 11

At what hood temperature should the turbine be tripped?

Answer 11

225°F (Admin Turbine Trip per MAP K-1-2).

Question 12

How does HS-V-6 control valve operate?

Answer 12

Begins to OPEN at 8# (145°F) and full OPEN at 15# (180°F). Fails CLOSED on loss of air.

Question 13

What is the purpose of HS-V-2 manual bypass?

Answer 13

Prevents high exhaust temps during startup up to 15% power due to slow response of HS-V-6.

Question 14

Where is HS-V-4 throttle located, and what is its function?

Answer 14

Located TB 355’ West under “C” LP Turbine Skirt. Ensures pressure of 30# at spray nozzles with HS-V-6 full OPEN.

Question 15

What actions should be taken if high hood temperature or HS-V-6 malfunctions?

Answer 15

OPEN HS-V-2 bypass. At low loads, raise load if possible (MAP K-1-2).