Feedwater/Feed Pump Turbine System

Question 1

What is the purpose of the FW system?

Answer 1

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.

Question 2

What is the purpose of the MFWPs?

Answer 2

Provide motive force to raise the pressure of the supplied condensate from around 350psig to around 1200 psig to overcome the S/G pressure.

Question 3

what type of impellers are utilized on the MFWPs?

Answer 3

Double suction

Question 4

What system provides lube oil for the bearings on the MFWPs?

Answer 4

Steam generator feedwater pump turbine lube oil system

Question 5

What capacity are each of the feed pumps designed to handle rated power? what is the procedural limit?

Answer 5

65% of the total required flow.
Procedurally limited to 62% during a downpower to remove one FWP from service

Question 6

What pressure does the seal water enter the feed pump casing form the gland seal regulator?

Answer 6

150psig

Question 7

Where does this seal water come from?

Answer 7

Condensate service header

Question 8

what is the purpose of the 2, 2.5 inch “Y” strainers in the seal water lines?
how many are normally in service?

Answer 8

to protect FWP seals from damage due to solids.
1 in service

Question 9

What D/P is normally maintained across the seals by the gland seal regulators?

Answer 9

15psid

Question 10

What output pressure do the gland leak off regulators maintain?

Answer 10

135psig

Question 11

how much air pressure is utilized in the new inpro seals?

Answer 11

1 psig

Question 12

What is the purpose of the mini flow valves?

Answer 12

To open or close as feedwater flow changes to maintain approx 5000gpm thru the MFWP to prevent overheating

Question 13

why does the mini flow valve shut when the MFWP trips?

Answer 13

to prevent the pump from freewheeling due to condensate system flow thru the mini flow valve to the condenser

Question 14

When would the mini flow valve fully open?

Answer 14

When the pump discharge valve is fully shut

Question 15

How do the mini flow valves fail on loss of IA?

Answer 15

full open

Question 16

the mini flow valves use how many air boosters for positioning?

Answer 16

2, one for opening and one for shutting

Question 17

what happens to the mini flow valve when feed pump turbine lube oil pressure drops below 75 psig? why?

Answer 17

Go closed to prevent pump from freewheeling due to feedwater flowing thru an idle pump

Question 18

how are the mini flow valves affected by a loss of 120VAC?

Answer 18

Fails open. if the FWPT trips or is already tripped the valve will close due to the energization of the DC solenoid

Question 19

how are the mini flow valves affected by loss of 125 VDC?

Answer 19

Normal ops, no effect.
If FWPT is tripped, a loss of DC will result in the valve failing open

Question 20

How often is the HP stop valve tested? any precations?

Answer 20

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.

Question 21

HP and LP control valves are operated by one hydraulic cylinder. Due to mechanical arrangement which valve opens first?

Answer 21

LP control valve

Question 22

What is the difference between the HP and LP stop valves concerning design features?

Answer 22

LP stop valve has its own valve body and when testing the LP stop valve it only goes half way closed

Question 23

Why is there a pressure switch installed on the control oil pressure line?

Answer 23

Acts to close the turbine control valves whenever the FWPT is tripped.
This prevents an uncontrolled start which could occur since on turbine reset the LP and HP stop valves immediately go wide open

Question 24

what controls the speed of the FWPT?

Answer 24

Main feedwater control system

Question 25

What system is the Feedwater control system part of?

Answer 25

Reactor control system

Question 26

What are the 2 normal sources of steam to the feed pump turbines?

Answer 26

main steam and reheat steam from the MT system MSRs

Question 27

What is the 3rd source of steam for the MFPTs?

Answer 27

Aux steam

Question 28

what is the flow path for the MSR reheater to the feed pump?

Answer 28

Flow thru the low pressure stop valve and low pressure control valve. 'D' MSR

Question 29

What is the flow path for the main steam to the feed pump?

Answer 29

flows thru the high pressure stop valve and high pressure control valve

Question 30

What is the normal source of steam?

Answer 30

low pressure reheat

Question 31

When would we use high pressure steam in MFWP?

Answer 31

During startup and to supplement the low pressure system during periods of light MT loads or overload on the FWPT

Question 32

When would we use AS for feed pumps?

Answer 32

Testing

Question 33

What ultimately controls the stop and control valves?

Answer 33

FWPT control oil

Question 34

what system provides shaft sealing steam to A and B FWPTs?

Answer 34

Turbine steam seal and drain system (GS)

Question 35

What cools the feed pump oil system?

Answer 35

NC

Question 36

Where do the FWPTs exhaust to?

Answer 36

'A' and 'B' condenser reheat trays and into the 'c' condenser

Question 37

Where are the FWPT drains directed to?

Answer 37

'A' and 'B' condenser sections

Question 38

how many wheels make up the feed pump turbine?

Answer 38

6

Question 39

Where are the thrust wear trip and overspeed trip governors located?

Answer 39

HP end of the rotor and are part of the rotor assembly

Question 40

where is the engagement gear for the turning gear located?

Answer 40

exhaust end of the rotor

Question 41

What is the normal position of the turbine drain valves under full steam load?

Answer 41

normally closed

Question 42

If the turbine drain valves are closed, how do we remove condensate during normal ops?

Answer 42

They are provided with a continuous bypass drain line thru an orifice

Question 43

What is the purpose of the feed pump turning gear?

Answer 43

to provide low speed turning of the rotor for cooling or heating up to prevent warping

Question 44

What is the interlock associated with the feed pump turning gear and what is it trying to prevent?

Answer 44

2 pressure switches, 1 monitioring oil pressure on the feedwater pump bearings and the other monitor the oil pressure to the turbine bearings. a low pressure in either switch will prevent the turning gear motor from operating. This interlock is for bearing protection.

Question 45

Where is the feed pump turning gear normally operated from?

Answer 45

control room

Question 46

What are the various FWPT trips?

Answer 46

1)Turbine bearing low oil pressure 2)Pump bearing low oil pressure 3)Exhaust vacuum low 4)Feedwater pump suction pressure low 5)Feedwater pump discharge pressure high 6)Thrust bearing wear high

Question 47

What are the three feedwater turbine thrust bearing test switches?

Answer 47

Thrust wear device test switch Active thrust wear test switch Inactive thrust wear switch

Question 48

What nominal set point is the mechanical overspeed trip tested to?

Answer 48

110%

Question 49

What is another way to test out the overspeed without getting up to that speed setpoint?

Answer 49

A jet of oil, controlled by a solenoid valve, can be sprayed into the emergency governor housing to unbalance the plunger and actuate the emergency trip at speeds up to rated

Question 50

During a startup, when is the first main feed pump started?

Answer 50

Prior to exceeding a reactor power of 3% which is the capacity of 1 AFP

Question 51

When is the 2nd MFWP started?

Answer 51

50% power

Question 52

Prior to startup what must be done with the Condensate/feedwater systems to improve the water quality?

Answer 52

Long path recirc

Question 53

During normal operation when can i secure one of the FWPs?

Answer 53

If plant load decreases below 62%

Question 54

What is meant by "Standby" when referring to the MFWPs?

Answer 54

The pump and turbine are in a warmed and ready condition

Question 55

After each shutdown, why is the main feedwater system placed in long path recirc?

Answer 55

For shutdown chemistry control and system cooldown

Question 56

What will happen if i lose a feedwater pump while at 100% power?

Answer 56

Reactor power cutback, lowering reactor power and turbine power to within capacity of a single main feedwater pump

Question 57

What will happen if we lose a FWP while at 100% power?

Answer 57

Reactor would trip on low S/G level. S/G level would have to be maintained by aux feed system