Main Feedwater Flashcards
What are the MFP trips?
- 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#)
What causes a Feedwater Isolation (FWI)?
- 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)
What supplies the normal steam supply to the MFPs?
- Reheat Steam (Norm)
- Main Steam for start-up up to about 55%-60% but available up to 100% power if necessary
What happens on a FWI?
MFPs Trip
MFP Disch Valves Close
FRVs Close
FMOs Close
What must you do to clear a FWI that is associated with P-4 with Tavg < 554°F)?
- Cycle a Rx Trip Breaker
Will all 4 MFW FRVs close on loss of 250v DC ctrl pwr?
Yes
When will the MFP Seal Water Pump auto start?
less than 15 psid between CBP Disch pressure and MFP suction pressure
Where can the MFP seal water pump get its suction from?
- Normal: CBP Discharge
- Alternate: U1 CST
- Alternate: HWP Disch
What is the FW designed to handle on a load rejection?
-10% step change
OR
- 5%/min ramp load change w/o steam dump
When is a MFP forced to Speed Ctrl?
- 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
What flow do the MFP ELOs modulate to maintain?
4000 GPM (Suction flow)
How much flow can each string of MFW heaters handle?
80% flow
How much flow can MFW heaters bypass valve (FMO-260) handle?
20% flow
Where does the E MFP ELO discharge to?
B Condenser
Where does the W MFP ELO discharge to?
A Condenser
Which FW heaters on Unit 1 receive HP steam?
Heaters 5 and 6
Which FW heaters on Unit2 receive HP steam?
Heaters 4, 5, and 6
Can you manually close the MFP ELOs?
- Yes, you can manually close MFP ELOs but only if the MFP stop valves are closed
Does the U-2 DC Lube Oil Pp go thru the Lube Oil Cooler?
- No, the DC Pump bypasses lube oil cooler
For a FWI, is the closure of the FRVs Train Specific?
No, either train of RPS will get all 4 FRVs
For a FWI, is the closure of the FMOs Train Specific?
Yes! Interlocked to the Rx Trip Breakers, so if one doesn’t go open, you don’t get that train of FMOs to close
What is the purpose of the Air Assist Check Valves in the MFW System?
keeps check valve out of flow stream
What is the purpose of the MFP Seal Water FRV?
Maintains seal water leak off temperature at 150°F
What are the MFP Speed Control Inputs?
SG Pressure, FP Discharge Pressure and Total Steam Flow
How is the Main Feed Pump DP calculated?
using the difference between the Lowest FW Pressure and the Highest Steam Pressure (bypass header)
If packing is adjusted on a valve, could there be any tech spec implications?
Yes, if the valve is required to be timed, the stroke time may not be met
While at 100% power onditions, MFP seal water can be normally supplied by _____ discharge and Alternately supplied by ____ discharge.
CBP
Seal water pump
What is the purpose of low flow feedwater heating?
To reduce thermal stress on the feedwater elbows at the SG nozzle area
What are the MFP LO Coolers cooled by?
NESW
Is a FWI Signal a DIRECT signal to automatically trip the MFP?
NO!!! It is not a direct signal.
What indications/Systems should be checked prior to opening MFP ELOs? Why?
Ensure that the FW pump oil system is operating to prevent damage to the FW pumps due to condensate flow spinning the pumps.
What is the Low Condenser Vacuum trip for Unit 1 MFP?
20” Hg
What is the Low Condenser Vacuum Trip for Unit 2 MFP?
15”
What is the loss of suction pressure trip for the MFPs?
Less than or euqal to 180 psig for 5 secs
