Condensate and Feedwater Flashcards
Starting interlocks of the A MFP (Motor driven)
- One CD/CDBP running
- Good oil pressure
- FW002A open (discharge valve)
- CB005A open (suction valve)
- FW027A open (Manual recirc isolation)
P2A MD MFP trips: (7)
- Electrical (OC, Grnd OC, Diff OC, UV)
- High lube oil temperature (175F)
- Low lube oil pressure (10#)
- P-14
- SI
- Low suction pressure (282#)
- No CD/CBP running
2B/2C turbine driven MFP starting interlocks:
- FW027B/C manual recirc open
- FW012B/C Recirc AOV open
- Turbine reset/latched
- HP and LP stops open
2B/2C Turbine driven MFP trips (7)
- Overspeed (5720 rpm)
- Low exhaust vacuum (14” Hg bypassed on startup)
- Low lube oil pressure (10#)
- P-14
- SI
- Both HP and LP stops closed
- Manual
SU feed pump has _____ starting interlocks, which are ______. SU feed pump will trip on _______.
No
None
1. Electrical (OC, Grnd OC, UV)
2. Low lube oil pressure (<5#)
SU feed pump is normally used at what power level?
<15%
To reset FWI from P-4:
Reset FWI 2/2 pushbuttons in “Yellow” on MCB
Reset FWI auxiliary relays 2/2 pushbuttons
Cycle RTBs to reset P4
To reset FWI from P-14
Restore all SG levels to normal
To reset FWI from SI
Reset SI to clear input
Cycle RTBs to momentarily clear P4 seal in
Reset FWI 2/2 pushbuttons in ‘yellow’ on MCB
Reset FWI auxiliary relays
CD152 is the _______ valve and begins to ______ and is full closed when ______.
AE/GS condenser bypass valve/ condensate recirc to condenser
Modulate closed >2100 gpm and
is full closed >7130 gpm based on highest flow reading
What is purpose of the FW heaters?
Improve efficiency and limit thermal stresses of SG
Where is the condensate collected in the heater directed?
Back to the condensate system via HDT or back to the condenser.
How is fine control of SG level maintained at all power levels?
Feed reg bypass valves at low power and FRVs >20% power.
CD/CDBP trips: (4)
- Phase overcurrent
- Ground overcurrent
- Lube oil pressure <4.0 psig
- Bus UV
CD/CDBP start interlocks
Sufficient lube oil pressure on both CD and CDBPs, 6 psig.
When does FWI occur?
RX trip with low Tave (564F)
Hi-HI SG level P-14
SI
What portions of CD/FW are safety related?
MFW check valves to SGs and FW035s to SGs
What major components exhaust to the main condenser?
TDMFWP turbines, main turbines (LP) and Steam dumps
How is vacuum in the main condenser maintained?
Condensing action of the steam
-and-
Air ejectors to remove air and non condensibles
Why is condenser level selection swapped from one side to the other when power is changed?
Lowest side is always selected to ensure adequate NPSH for the CD pumps. At low power the pump recircs raise the west side level. At high power the heater inputs raise the east side level.
CD-210A/B are the ________ valves and receive an open signal when______.
Condensate pump common discharge valves
Downstream pressure reaches 35 psig (CDBP low suction pressure)
CD157A/B are the _______ valves and work with _____ to maintain a total flow of ______. They also automatically open when ______.
GS condenser bypass valves
CD152 recirc to condenser
7130 gpm
Low FW pump NPSH signal
CB113A/B/C/D are the ____ valves and auto open when CDBP discharge flow rate drops to less than ____.
CDBP recirc valves
1700 gpm, full open at 839 gpm
Standby CDBP recirc valve kept _____ to prevent _____.
Closed
Flow through idle pump back to condenser
How is adequate oil pressure indicated in the MCR for a CD/CB pump?
White “OIL PRESS UP” light lit above AO pump H/S
What will auto start a CD/CB aux oil pump on the STBY CD/CB pump?
Low FP NPSH or low lube oil pressure (< 5 psig)
What interlock must be met to allow a manual or auto start of a CD/CB pump?
Adequate oil pressure – 6 psig
What conditions must be met to allow an auto start of a CD/CB pump?
Selected to STBY, C/S in NAT, Low NPSH present, and adequate oil pressure
If bus 143 is de-energized, what CD/CB pumps are affected?
1A and 1C pumps CB recirc valves will fail open, 1CD152 will fail open, and no power to the 1A/1C CD/CB pp aux oil pumps.
What will automatically trip a CD/CB pump?
Phase A/C or Ground OC, UV on Bus, or Low oil pressure on CD or CB pumps
How is condensate flow through the air ejectors controlled?
Minimum flow is established by CD152. As flow increases, a hinged baffle plate in each condenser allows more flow to bypass
If low NPSH is sensed, what happens to CD152 and CD157A/B?
CD152 closes, CD157A/B open