U2 Main Turbine Cooling/SS/LO

Question 1

What are the trips of the Unit 2 Main turbine that are DIFFERENT than Unit 1?

Answer 1

Hardwired:
S tator Cooling Water (10 sec delay)
- Lo Press 28 psig
- Lo Flow 666 gpm
- Hi Temp 95°C (+ 5 sec delay)
T hrust Bearing Wear Abnormal ± 32 mils

PLC:
O il Press (Bearing) < 14.7 psig > 5 seconds

Question 2

Is there an auto trip for high vibrations trip for the Unit 2 Main Turbine?

Answer 2

NO

Question 3

When does the U2 Turning gear auto start?

Answer 3

1 min after Main Turbine Trip. Does not engage until < 40 RPM

- Engages when Main Turbine speed < 40 rpm.

Question 4

When does 2-CMO-40 (Exhaust hood spray) open?

Answer 4

• Generator Load < 7.5%
• Turbine Speed > 900 rpm
• Manual

Question 5

What does the Main Turbine Thrust Bearing do?

Answer 5

Limits Axial Movement to prevent stationary and rotating blade contact

Question 6

When does the AC Lube Oil pump supply oil to the U2 Main Turbine?

Answer 6

Turbine speed < 1800 rpm

Question 7

When does the AC Lube Oil pump auto start for the U2 Main Turbine?

Answer 7

Turbine Trip

- Low Lube Oil # at 16#

Question 8

When do the 2 DC Lube Oil pumps auto start for the U2 Main Turbine?

Answer 8

• Turbine Trip
  -Low pressure of 16 psig

- Low Lube Oil # at 16#

Question 9

When do the 2 DC Lube Oil pumps supply oil to the U2 Main Turbine?

Answer 9

supplies bearing oil when the Shaft Driven LO Pump or Aux Oil Pump fail

Question 10

What does LRV-32, LO supply header # Reg Valve, do?

Answer 10

• Maintains U2 turbine supply header pressure at 24.5 psi by dumping excess pressure back to the lube oil tank

Question 11

What do the reheat stop and intercept valves do?

Answer 11

• Both Close on Main Turbine Trip to minimize the potential for overspeed of Main Turbine
• Intercept valves throttle to limit overspeed on a load rejection to prevent a turbine trip

Question 12

How do the SRV-26/27, aux steam supply valves fail on U2?

Answer 12

As is

Question 13

What does SRV-12 (U2 MS Bypass Header supply to steam seals) do?

Answer 13

Keeps HPT Inner Steam Seals 10# > HPT exhaust during normal operation.

Question 14

What supplies LPT Steam Seals during normal operation?

Answer 14

• HP inner seals supply most of steam for seal stm header after it exits the HPT
• Can receive some steam from HP and LP Stop and Ctrl valve leakoff,
• and some aux steam as necessary when HP and LP stop and ctrl valves are backseated

Question 15

What supplies Steam Seals during startup, shutdown and low power operation?

Answer 15

50# aux steam supplies steam seals

Question 16

What dumps excess steam pressure for the steam seals on U2?

Answer 16

SRV-25 (Steam Seal Dump Valve) controls pressure and dumps extra steam to 2A/2B Heaters

Question 17

How does SRV-22 (Aux Steam reg supply valve) fail on loss of air?

Answer 17

Fails open

Question 18

How does SRV-25 (Seal disch to 2A/B heaters) fail on loss of air?

Answer 18

-Fails closed

Question 19

When do the U2 bearing lift pumps auto start?

Answer 19

Turbine Trip

Question 20

Where in the Lube Oil Flowstream does the DC Emergency Lube Oil Pump discharge?

Answer 20

After the Lube Oil Coolers (bypasses them)

Question 21

What effect will long term operation on the DC Emergency Lube Oil pump have?

Answer 21

Higher LO temps

Question 22

The Unit 2 High Pressure Turbine inner steam seal is supplied with Main Steam which normally is controlled ____ psi greater than turbine exhaust pressure.

Answer 22

10#

Question 23

How do we prevent the MT from tripping on a Rx trip?

Answer 23

Knife switches are opened to allow turbine to stay on grid when Rx is tripped (prevents turbine overspeed)

Question 24

How do you adjust the Gland Steam Condenser vacuum?

Answer 24

Adjust the blower suction inlet orifice plate (sliding damper) position

Question 25

What supplies steam during turbine startup?

Answer 25

• Intermediate pressure header
  Aux steam
• High pressure header
  Main steam

Question 26

If you lose the glad steam condenser fan, what will happen?

Answer 26

Steam will leak out turbine and MPF to atmosphere

Question 27

What is the Bases behind T.S. 3.3.1, Reactor Trip from Turbine Trip above P-8?

Answer 27

• Anticipates loss of heat removal
• Minimizes temperature and pressure transient
• Auto Oil Stop pressure and Turbine Stop Valve position provides diversity of turbine trip indication

Question 28

What is the different for the stop and control valves going into the HP Turbine between the units?

Answer 28

Unit 1 equalization line is between stop and control valves. Unit 2 valves are combined