U1 Main Turbine Cooling/SS/LO

Question 1

What are the U1 MT Trips?

Answer 1

Hardwire Trips
- Reactor Trip
- AMSAC (activated at > 40% pwr, auctates at < 25% FW flow 3/4)
- SI
- Overall HEA
- Unit HEA
- IOPS 110%
- Loss of SCW (10 second delay)
- Low Pressure 13 #
- Low Flow 195 gpm
- High Temp 95°C (+ 5 second delay)
- Thrust Bearing Wear Abnormal > 39 mils (axial)
- Manual
- P14 (SG Hi Hi Lvl at 67% 2/3 on 1 SG)

PLC Trips
- Low EHC # 1100#
- EHC 2/3 < 800#
- Overspeed 107%
- Low Bearing Oil # < 8# for 5 sec ***
- Low Condenser Vacuum ≤ 24.1” Hg OR 30 minutes < low setpoint (variable)
- Loss of both DCS Pwr supplies

Question 2

What auto starts a AC Suction LO Pump on U1?

Answer 2

• Low Suction Press < 10# from the Shaft Driven Oil Pump
• Turbine Trip

Question 3

What auto starts a DC Emergency Bearing Oil Pump on U1?

Answer 3

• Low discharge press < 125# from the Shaft Driven Oil Pump WITH Turning Gear oil pp discharge press < 10# ***
• Turbine Trip

Question 4

What auto starts the Turning Gear Oil pump and the DC Backup Oil Pump?

Answer 4

• Bearing Header pressure < 15#
• Turbine Trip

Question 5

When do the Bearing Lift Pumps auto start?

Answer 5

• Auto start on Turbine Low Speed Switch only (Does NOT start on turbine trip)

Question 6

When do Bearing Lift Pumps 2 and 4 start?

Answer 6

• Start 20 seconds after Turning Gear engagement to ensure sufficient drag on turbine shaft to prevent the Turning Gear from disengaging

Question 7

What are the Bearing Lift Pumps interlocks?

Answer 7

• Interlocked to have Lift Pump suction pressure of > 8# to start Lift Pump

Question 8

When do lift pumps stop?

Answer 8

• Lift Pumps stop when suction pressure < 2#.

Question 9

Which stop valve allows pre-heating of chest and shell (HPT)?

Answer 9

• # 2 Stop Valve

Question 10

When does the U1 Turning Gear auto engage?

Answer 10

• When the turbine tops (< 1/2 rpm)

Question 11

What are the U1 Turning Gear interlocks?

Answer 11

Will start if:
- 1 oil pump on (Turn Gear Oil, Backup Oil, Emerg Oil)
- Bearing oil # > 25#
- Lift pump disch # > 440# (Except pumps 2 & 4)
- Bypass buttons available
for lift pumps and #2 Stop Valve interlocks
- Main Turbine stop valves closed

Question 12

What is the turning gears purpose?

Answer 12

• Prevents/removes turbine bow on the shaft
• Removes a temporary rotor bow during turbine warm up, before a turbine roll

Question 13

At what speed does IOPS start sensing speed of the turbine?

Answer 13

• 100 rpm

Question 14

What are the Main Turbine Vib alarms?

Answer 14

• high at 8 mils
• High High at 14 mils (Bearings 3-8) and 12 mils (bearings 1, 2, 9-12)
• Manual Trip required on Turbine Vib High High

Question 15

What does the Thrust Bearing maintain and support?

Answer 15

• Limits axial movement of the turbine rotor to prevent stationary and rotating blade contact

Question 16

What does the Journal Bearing maintain and support?

Answer 16

• Support the weight of the turbine and generator rotors and restrict movement to axial direction only

Question 17

What do the Combined Stop/Intercept valves do?

Answer 17

• Control flow of steam from MSRs to 3 LPTs
• Close on turbine trip to avoid overspeed due to steam in MSRs***

Question 18

Which turbines have a rupture disc and when does it rupture?

Answer 18

• LPTs contain rupture discs that release if pressure exceeds 5#

Question 19

What does 33VED (Turbine Trip) provide?

Answer 19

• Generator Motoring Alarm
• Starts Motor Suction Oil Pump
• DC Emergency Lube Oil Pump
• DC Backup Oil Pump
• Actuation of Overall Differential HEA

Question 20

What does Overall Differential HEA actuate?

Answer 20

• Open Generator Output Breakers
• Opens Generator Field Breakers
• Fast Bus Transfer to RAT
• Enables Main Transformer Fire Deluge Valve

Question 21

What are Main Turbine Steam seals supplied by during startup, shutdown, and low load operation?

Answer 21

• 50# Aux Steam (SRV-10 and SMO-10) (Maintains steam seals at 4#

Question 22

What are Main Turbine Steam seals supplied by during normal operation?

Answer 22

• leakage from exhaust of HPT and MFPTs supply steam to LPTs and MFPT exhaust end seals, SRV-11 ctrls at 4#

Question 23

Where does SRV-11 dump to?

Answer 23

• 1 A/B heaters

Question 24

How does SRV-10 Fail(Aux Steam supply to Steam Seals)?

Answer 24

• Fails Open

Question 25

How does SRV-11 Fail (Steam Seal Dump Valve?

Answer 25

• Fails closed

Question 26

What are the EHC pump auto starts?

Answer 26

Auto 1 - 1450#
- if run pump goes to status other than run or test
- 3/3 EHC transmitters fail
- Auto 1 Test Signal
Auto 2 - 1375#
- Auto 1 Test Signal

Question 27

What will trip an EHC heater?

Answer 27

• Low Low EHC tank Lvl

Question 28

What does SRA-1800 look for on U1?

Answer 28

• Primary to secondary tube leak

Question 29

What will isolated on a Extreme High Lvl in the Gland Steam Condenser?

Answer 29

• CMO-630 (TACW supply valve) will isolate

Question 30

What maintains the bearing oil header pressure for the U1 Main Turbine?

Answer 30

• 1-SV-248 maintains it at 25#

Question 31

What are the EHC loads?

Answer 31

• Main Feed Pumps
• Main Stop Valves
• Front Standard
• Main Control Valves
• Right Intermediate Valves
• Left Intermediate Valves

Question 32

If starting up, what is supplying steam seals and how are srv-10 and svr-11?

Answer 32

• SRV-10 is throttled open and SRV-11 is closed