AF Flashcards
Where does AFN take suction from in shutdown conditions?
CST
What is the purpose of the aux feed system?
Provides sufficient reserve of feed water to permit the plant to operate in hot standby for 8 hours to the point where SRC can be placed in operation.
Where does AFN discharge to during shutdown conditions?
Fills the SGs through the main feed downcomer control valves or the control valve bypass valves.
Where does the recirc flow from AFN discharge?
Flow returns to the CST no matter where it’s suction was taken.
What is the backup water source for all AFW pumps?
RMWT
Must be manually aligned
What provides room cooling for the I essential pump rooms during normal standby operation?
Aux building normal AHUs
What system provides electrical control power for AFA?
PK class 125 Vdc
What pump is used during hydrazine and ammonia additions to the secondary?
AFN
What is the power source for AFN.
PBA
What is the power source for AFB?
PBB
What supplies power to all the B train valves?
PH
What supplies the motive force for AFA
Main steam
What provides the motive force for overspeed trip testing of AFA?
Aux steam
What will automatically occur if one aux feed pump room experiences flooding?
The air inlet and outlet dampers will close to prevent flooding in both rooms
What are the two sources of control power for AFN?
PK and “A”train class battery charger
Where can AFN be controlled from?
Locally at the breaker on PBA-S03
Control room
Where does the suction of AFN tap into the CST?
Same level as the other AF pumps
What is unique about the hv1 and hv4 and their piping connection to the CST?
Between the CST and valves the piping is class (seismically rated) downstream of the valves until the AFN pump is non class.
What is the normal position of HV1 & HV4?
They are normally closed for seismic considerations
Where can an 86 lockout on the AFN pump be reset?
Either locally at the breaker or from the control room
How is AFB pump cooled and lubricated?
It’s provides its own bearing lubrication using dipper rings that throw oil on the bearings.
The lube oil is cooled via two oil coolers that use a slipstream from the first stage pump discharge.
Where can and 86 lockout on AFB be reset from?
Locally at the breaker or control room.
Where is AFB located?
81’ of MSSS in a separate room.
How is AFA lunricated?
It is provided with its own lube oil system. The turbine shaft is coupled with a LO pump that supplies oil to the pumps and turbine governor actuator.
What provides cooling to the AFA pump?
It provides it’s own cooling water to the LO cooler from the first stage of the pump.
What drives the governor actuator?
It’s is driven by the same worm gear that drives the LO pump.
Under what conditions do we use the AFA pump
Blackout
Where is steam for AFA provided from?
Either SG, upstream of the MSIVs.
What can be done to minimize radiological release if one SG has a tube leak and AFA is required?
The steam supply for AFA can be switched to the non leaking SG.
Where is AFA located?
81’ of MSSS in a separate seismic category 1 room.
What is the purpose of the AFA turbine trip and throttle valve?
Acts as a trip valve during operation. A spring loaded mechanism provides closing force when the valve is tripped and the stem is unmatched from the motor actuator.
How can the AFA overspeed trip mechanism be reset when it has tripped due to mechanical overspeed?
The NLO will be called upon to reset the valve locally
How can the AFA overspeed trip mechanism be reset when it has tripped via pushbutton?
The trip can be reset at the control room via hand switch because the mechanical linkage connected to the governor has not changed positions.
Where can the manual electrical trip be initiated from?
Control room,
remote shutdown panel “a”
and local turbine control panel
What is the purpose of the AFW flow regulating valves and where are they located?
Controls flow of water to the SGs, located on the discharge piping in the AFW pump rooms
What is the purpose and location of the AFW flow isolation valves?
Located on the discharge side of the AFW pumps, downstream of the regulating valves and in the associated pump room.
What is the power source for the motor operated valves for AFA?
PK
What is the power source for the motor operated valves on AFB and AFN?
PH
What feature has been installed in the AFW isolation valve bonnets to prevent them from locking?
A relief valve is installed.
Relief discharge is routed to the CST via mini flow lines for the respective pump.
If there is a 185 psid between SG 1 and SG 2 what does that indicate?
A break in the main steam or main FW line.
What happens when an AFAS 2 is signaled?
Identical actions as AFAS 1 but only the isolation and flow control valves associated with feeding SG 2 are cycled automatically
When is AFN utilized under normal conditions?
During start up to maintain SG levels until reactor power reaches 2%
What condition could occur if backleakage from the SGs flows into the AFW system through ISO and check valves? What is used to monitor for this condition?
Steam binding
Could result in water hammer
Temp indicating strips on the discharge side of the pumps
Will change color from black to blue/green in high temp.
