Aux Feed Flashcards
Where do the Aux feed pumps receive water from for the Steam Generators?
CST
What provides the motive force for Aux Feed ‘A’?
Steam from main steam
What is the mission time for the Aux Feed system?
13 hours and 20 minutes
What is the backup source of water for the class aux feed pumps?
RMWT thru V019
During a loss of off-site power. What can AFN do for us?
It can provide aux feed to the SG’s for 8 hours using the downcomer FW control and isolation valves
When do we get an AFAS?
25.8% SGWL WR 2 out of 4
What happens on an AFAS?
Both class AF pumps start (A and B) Both EDG's start and their auxiliaries S/G blowdown and sampling isolates Flow control and block valves open until 40.8% wide range is acheived
What happens on a SIAS/CSAS?
B AFP starts. N AFP trips if runnings
Both EDG’s start and their auxiliaries
Sias and LOP or LOP. DG autostart.
B Aux feed pump starts. N AFP trips if runnings.
Where do the class aux feed pump room drains go to?
RD system
What provides cooling to the room coolers in the class aux feed pump rooms?
Essential Chill water
What are the class AFP rooms normally cooled by?
Aux Bldg normal AHU
What happens on a high level in a class aux feed pump room?
At approximately 3’ 6” the room dampers will close
What is a delta-p lockout?
When one SG is 185 psig lower then the other one. Feed is stopped to the lower pressure generator.
What is the minimum pump speed to provide adequate oil lubrication of the pump sleeve bearings and pump internals from the shaft driven LO pump?
1000 RPM
Where does AF lube oil cooling water come from?
1st stage of the pump
Where do AF pump room drains go to?
RD system
What cools to the Aux feed pump room coolers inside the pump rooms?
EC
When Aux feed is in its normal standby alignment. What cools the rooms?
Aux Building normal AHU’s
If one of the Aux feed pump rooms has a high level, what happens?
At 3’ 6” the adjoining room dampener will automatically close.
What is a delta-p lockout?
During an AFAS if one of the SG has a 185 psid then the other one. The lower pressure SG will stop receiving feed to prevent feeding a steam leak.
If Aux Feed ‘A’ is running and we lose PKA, what is going to happen?
Lose governor control power, trips on overspeed
Steam supply valves fail as is
Aux feed isolation valves fail as is
What happens to Aux feed ‘N’, if we lose PKA?
Lose control power. Switch to alternate off of ‘A’ class battery charger. Downcomer isolation valves fail open.
Why do we have the temperature indicating strips in the aux fed discharge piping?
We don’t want steam getting back into the discharge piping. It could gas bind the pump and cause water hammer upon flow initiation.
Why do the main steam supply bypass valves open for 30 seconds on a start signal to AFA?
- Allow the turbine to gain sufficient speed to raise governor oil pressure. This allows the governor to close down on the steam admission valve (HV-54); which prevents a turbine overspeed.
How is HV-54 (trip and throttle valve) maintained in standby or normal operation?
It is maintained open
What are the indications locally that AFA has tripped on overspeed?
-HV-54 linkage will not be latched
- On AFA local panel
Motor light will be green
Valve position light will be green
Over-speed light will be illuminated (white)
If HV-54 has been manually tripped what indications do you have locally?
On AFA local panel
- Motor light will be red
- Valve light will be green
Can be reset from CR, RSP or locally at panel
What is AFA’s rpm set at?
Approx. 3600 RPM
Explain local operation of AFA.
- Check HV-54 is closed
- Open control power breaker on PKA-D21
- Place local pressure gauge in service
- Check HV-54 is reset
- Open steam supply valve (134/138)
- Open iso valve to SG
- Contact w/ CR, throttle HV-54 to obtain req flow
Explain local operation of AFA during a delta-10.
- Safe travel path
- D-10 box (leather gloves, tach, procedure, phone)
- Contact CR
- HV-54 closed
- Dis. Pressure gauge in service
- HV-54 is reset
- Isolation’s to SG’s closed
- Open HV-54 to obtain 3560 RPM or 1800 psig
- Throttle SG iso to obtain 1400-1410 psig (10 minutes)
- Adjust HV-54 to obtain 3560 RPM
- Throttle SG iso 1680-1690 psig (15 minutes)
- Throttle SG iso 1730-1740 psig
- HV-54 to 3560 RPM
What allows for constant draining of the aux feed pump ‘A’ steam supply line?
A large condensing pot located in the aux building
How does the aux feed pump oil system work?
- Oil pump is driven off of worm gear arrangement
- Oil pump provides own lubrication using dipper rings to throw oil onto bearings.
- supplies oil to the turbine bearings and governor actuator
In the standby position, what position would the trip/throttle valve be in?
Open
What position is the turbine governor valve when AFA is in standby?
Open by spring pressure
How is the aux feed pumps bearing oil cooled?
By two integral oil coolers that utilize a slipstream from the pumps 1st stage discharge. This water is then directed back to the pumps suction
Where is the valve to align aux steam to aux feed ‘A’?
V055. 100 foot TB on west side behind IA compressors
What are the AF critical steam traps; where are they?
M23 and M24. Both on the 100’ TB on west side near V055.
Explain CST levels
550,000 gallon capacity
330,000 gallons reserved for AF and emergency makeup
What are the AFA pre-starts?
- Pump bearing oil levels (inboard and outboard)
- Turbine inboard bearing
- AFA-P01 overspeed linkage reset
- Temperature strip
What are the AFB pre-starts?
- Pump bearing levels
- Motor bearing levels
- motor space heater energized
- Temperature strip
What is the preferred method to vent the AF pumps?
Using high point vent while flushing with CST water
What is the alternate method to vent an AF pump that is potentially steam bound?
Using the drain valve on the pressure instrument while flushing with CST water
At about what flow is AFA set to maintain?
3590 RPM
