Main Feedwater

Question 1

What are the MFP trips?

Answer 1

• Manual
• Rx trip
• SI
• Hi-Hi S/G level (P-14)
• IOPS (110%)
• Thrust Bearing position
• Overspeed (107%)
• Lo Condenser Vacuum (different per Unit)
• Lo Lube Oil press (4#) (5 sec TD)
• Lo Suction press (180#) (5 sec TD)
• Lo Trip Header Press (800#)

Question 2

What causes a Feedwater Isolation (FWI)?

Answer 2

• SG High-High level (P-14) (67% NR 2/3 on 1 SG)
• SI
• Rx trip (P-4) with low Tavg (Tavg less than 554°F on 2/4 loops)

Question 3

What supplies the normal steam supply to the MFPs?

Answer 3

• Reheat Steam (Norm)
• Main Steam for start-up up to about 55%-60% but available up to 100% power if necessary

Question 4

What happens on a FWI?

Answer 4

MFPs Trip
MFP Disch Valves Close
FRVs Close
FMOs Close

Question 5

What must you do to clear a FWI that is associated with P-4 with Tavg < 554°F)?

Answer 5

• Cycle a Rx Trip Breaker

Question 6

Will all 4 MFW FRVs close on loss of 250v DC ctrl pwr?

Answer 6

Yes

Question 7

When will the MFP Seal Water Pump auto start?

Answer 7

less than 15 psid between CBP Disch pressure and MFP suction pressure

Question 8

Where can the MFP seal water pump get its suction from?

Answer 8

• Normal: CBP Discharge
• Alternate: U1 CST
• Alternate: HWP Disch

Question 9

What is the FW designed to handle on a load rejection?

Answer 9

-10% step change
OR
- 5%/min ramp load change w/o steam dump

Question 10

When is a MFP forced to Speed Ctrl?

Answer 10

• Both MS Press Xmitters Fail
• Both MFP Hdr Press Xmitters Fail
• MFP DP Setpoint Xmitter Fails
• Other MFP Trip when greater than 60% Power as indicated by MFP DP
• MFP Speed > 5220 (5300) rpm

Question 11

What flow do the MFP ELOs modulate to maintain?

Answer 11

4000 GPM (Suction flow)

Question 12

How much flow can each string of MFW heaters handle?

Answer 12

80% flow

Question 13

How much flow can MFW heaters bypass valve (FMO-260) handle?

Answer 13

20% flow

Question 14

Where does the E MFP ELO discharge to?

Answer 14

B Condenser

Question 15

Where does the W MFP ELO discharge to?

Answer 15

A Condenser

Question 16

Which FW heaters on Unit 1 receive HP steam?

Answer 16

Heaters 5 and 6

Question 17

Which FW heaters on Unit2 receive HP steam?

Answer 17

Heaters 4, 5, and 6

Question 18

Can you manually close the MFP ELOs?

Answer 18

• Yes, you can manually close MFP ELOs but only if the MFP stop valves are closed

Question 19

Does the U-2 DC Lube Oil Pp go thru the Lube Oil Cooler?

Answer 19

• No, the DC Pump bypasses lube oil cooler

Question 20

For a FWI, is the closure of the FRVs Train Specific?

Answer 20

No, either train of RPS will get all 4 FRVs

Question 21

For a FWI, is the closure of the FMOs Train Specific?

Answer 21

Yes! Interlocked to the Rx Trip Breakers, so if one doesn’t go open, you don’t get that train of FMOs to close

Question 22

What is the purpose of the Air Assist Check Valves in the MFW System?

Answer 22

keeps check valve out of flow stream

Question 23

What is the purpose of the MFP Seal Water FRV?

Answer 23

Maintains seal water leak off temperature at 150°F

Question 24

What are the MFP Speed Control Inputs?

Answer 24

SG Pressure, FP Discharge Pressure and Total Steam Flow

Question 25

How is the Main Feed Pump DP calculated?

Answer 25

using the difference between the Lowest FW Pressure and the Highest Steam Pressure (bypass header)

Question 26

If packing is adjusted on a valve, could there be any tech spec implications?

Answer 26

Yes, if the valve is required to be timed, the stroke time may not be met

Question 27

While at 100% power onditions, MFP seal water can be normally supplied by _____ discharge and Alternately supplied by ____ discharge.

Answer 27

CBP Seal water pump

Question 28

What is the purpose of low flow feedwater heating?

Answer 28

To reduce thermal stress on the feedwater elbows at the SG nozzle area

Question 29

What are the MFP LO Coolers cooled by?

Answer 29

NESW

Question 30

Is a FWI Signal a DIRECT signal to automatically trip the MFP?

Answer 30

NO!!! It is not a direct signal.

Question 31

What indications/Systems should be checked prior to opening MFP ELOs? Why?

Answer 31

Ensure that the FW pump oil system is operating to prevent damage to the FW pumps due to condensate flow spinning the pumps.

Question 32

What is the Low Condenser Vacuum trip for Unit 1 MFP?

Answer 32

20" Hg

Question 33

What is the Low Condenser Vacuum Trip for Unit 2 MFP?

Answer 33

15"

Question 34

What is the loss of suction pressure trip for the MFPs?

Answer 34

Less than or euqal to 180 psig for 5 secs