Feedwater/Feed Pump Turbine System Flashcards
What is the purpose of the FW system?
Supply feedwater from the suction of the FW pumps to the feedwater regulating valves in the line to each S/G at the required pressure, temp and flow rate.
provide the final 3 stages of feedwater heating in two parallel heater trains.
What is the purpose of the MFWPs?
Provide motive force to raise the pressure of the supplied condensate from around 350psig to around 1200 psig to overcome the S/G pressure.
what type of impellers are utilized on the MFWPs?
Double suction
What system provides lube oil for the bearings on the MFWPs?
Steam generator feedwater pump turbine lube oil system
What capacity are each of the feed pumps designed to handle rated power? what is the procedural limit?
65% of the total required flow.
Procedurally limited to 62% during a downpower to remove one FWP from service
What pressure does the seal water enter the feed pump casing form the gland seal regulator?
150psig
Where does this seal water come from?
Condensate service header
what is the purpose of the 2, 2.5 inch “Y” strainers in the seal water lines?
how many are normally in service?
to protect FWP seals from damage due to solids.
1 in service
What D/P is normally maintained across the seals by the gland seal regulators?
15psid
What output pressure do the gland leak off regulators maintain?
135psig
how much air pressure is utilized in the new inpro seals?
1 psig
What is the purpose of the mini flow valves?
To open or close as feedwater flow changes to maintain approx 5000gpm thru the MFWP to prevent overheating
why does the mini flow valve shut when the MFWP trips?
to prevent the pump from freewheeling due to condensate system flow thru the mini flow valve to the condenser
When would the mini flow valve fully open?
When the pump discharge valve is fully shut
How do the mini flow valves fail on loss of IA?
full open
the mini flow valves use how many air boosters for positioning?
2, one for opening and one for shutting
what happens to the mini flow valve when feed pump turbine lube oil pressure drops below 75 psig? why?
Go closed to prevent pump from freewheeling due to feedwater flowing thru an idle pump
how are the mini flow valves affected by a loss of 120VAC?
Fails open. if the FWPT trips or is already tripped the valve will close due to the energization of the DC solenoid
how are the mini flow valves affected by loss of 125 VDC?
Normal ops, no effect.
If FWPT is tripped, a loss of DC will result in the valve failing open
How often is the HP stop valve tested? any precations?
Daily.(Weekly) look this up!
HP control valve must be closed before testing the stop valve.
There is an interlock which prevents testing the HP stop valve if the HP control valve is open.
HP and LP control valves are operated by one hydraulic cylinder. Due to mechanical arrangement which valve opens first?
LP control valve
What is the difference between the HP and LP stop valves concerning design features?
LP stop valve has its own valve body and when testing the LP stop valve it only goes half way closed