FW/FW Pump Turbine System

Question 0

How does the FW system interact with the condensate system?

Answer 0

Provides:
Water to the SG FW pump suctions
Gland seal steam to the SG FW pump seals
Return path for long path recirc and FW pump mini flow recirc
Provides the main condenser which receives FW turb exhaust steam, turbine and steam line drains, also provides exhaust vacuum.

Question 1

What is the purpose of the feed water system?

Answer 1

Supply FW from the suction of the SG FW pumps to the FW regulating valves in line to each SG at the required pressure and temperature, and flow rate.

Provides the final three stages of FW heating in two parallel heater trains.

Question 2

How does the main turning interact with the FW system?

Answer 2

Provides primary steam to the FWPTs via the low pressure stop and control valves.

FWPTs are usually fed by MSR D reheat steam.

Question 3

How does the SG system interact with the FW system?

Answer 3

Provides the steam to drive FWPTs when steam supply from the main turbine is insufficient.

Question 4

How does the aux steam system interact with the FW system?

Answer 4

Provides steam for FWPTs overspeed trip tests.

Question 5

How does the FW control system interact with the FW system?

Answer 5

A control signal that regulates the speed of the main FWPTs and the position of the FW regulating valves to maintain SG water level.

Question 6

How does GS interact with the FW system?

Answer 6

Provides shaft sealing steam to prevent air leakage out of the FWPTs.

Question 7

What is the purpose of the main FW pumps?

Answer 7

Provides the motive force to raise the pressure of the supplied condensate from ~350 psig to 1200 psig so that it can enter the SG.

Question 8

What lubricates the main FW pumps?

Answer 8

SG FW pump turbine LO system.

Question 9

What governs the feed water flow?

Answer 9

The speed of the turbine powering the pump.

Question 10

Where are the main FW pumps located?

Answer 10

110’ of the turbine building.

Question 11

What is used to prevent FW from leaking out of the FW pump?

Answer 11

Seal water.

Question 12

Where does seal water exit the pump?

Answer 12

Exits via the gland leak off piping and the gland leak off regulator.

Question 13

What happens the the sealing water that drips out of the pump shaft ?

Answer 13

It is directed to the steam packing exhauster drain tank.

Question 14

How are the gland seal regulators controlled?

Answer 14

Pneumatically. Desired pressure set via locally mounted pressure indicating controller.

Question 15

Where does gland seal water exiting the FW pumps go?

Answer 15

A main condenser.

Question 16

What is the purpose of the mini-flow valves in the FW system?

Answer 16

They open or close as FW changes to maintain ~7000 gpm flow through the FW pump to prevent pump overheating.

Question 17

What happens to the mini-flow valves on loss of air?

Answer 17

The valves fail open

Question 18

What happens to the mini-flow valves on Los of 120 Vac power to the controller?

Answer 18

Valve fails open

Question 19

What happens to the mini-flow valve after a FWPT trip?

Answer 19

The 125 Vdc solenoid a would energize sending a hard close signal regardless of the controller signal.

If 125 Vdc is lost then the valve would fail open.

Question 20

What position must the control valve be in to open the main FW pump high pressure stop valve?

Answer 20

The control valve must be closed.

The stop valve has a pilot valve that opens first to equalize pressure between the valves and allows the stop valve to open.

Question 21

What color is the light that indicates the closed position of the HP control valve?

Answer 21

Green

Question 22

What operates both the HP and LP control valve?

Answer 22

A single hydraulic cylinder.

Question 23

When is the high pressure steam used as the motive force for the main FW pump turbine?

Answer 23

During times of low power and insufficient heat from the D MSR.

Question 24

What operates the LP stop valve?

Answer 24

Hydraulically operated valve that allows for quick tripping either manually or automatically.

Question 25

What in the LP main FW pump stop and control valve prevents an uncontrollable start which could occur after resetting the LP and HP stop valves, since they go wide open after reset?

Answer 25

There is a pressure switch on the control oil pressure line.

Question 26

How many main FW pumps are there and what is there capacity?

Answer 26

2 pumps | 65% capacity each.

Question 27

What are the three sources of steam for the FWPTs?

Answer 27

Main steam- during start up (HP side) MSR D- normal operation (LP side) Aux steam- overspeed testing

Question 28

How is high pressure steam admitted to the FWPT?

Answer 28

Via a steam ring in the lower half of the high pressure casing

Question 29

How is low pressure steam admitted to the FWPTs?

Answer 29

Via nozzle plates directed along the shaft.

Question 30

How many stages are the FWPTs?

Answer 30

Six

Question 31

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

Answer 31

At the HP end of the rotor.

Question 32

Where are the FW turbine drain valves operated from and what is their purpose?

Answer 32

Operated from the control room Allows draining of condensed steam to prevent a slug of water from entering the turbine.

Question 33

Where is the turning gear for FWPTs normally operated from?

Answer 33

Control room.

Question 34

Where is the reset and jog button located for the FWPTs?

Answer 34

At the turbine

Question 35

What happens when the FWPTs are tripped?

Answer 35

The HP and LP stop and control valves go closed as well as the mini-flow valves. Valves open when trip is reset

Question 36

How can an operator manually trip the FWPTs?

Answer 36

Locally by pulling the manual trip lever located on the turbine from standard.

Question 37

What happens when the FWPTs overspeed?

Answer 37

Closes stop valves Device similar to sprag clutch rotates out due to centrifugal force and activates the trip button.

Question 38

How many feed pumps are required for <=62% plant load?

Answer 38

One

Question 39

What happens to the main FW system after each shutdown?

Answer 39

It is placed in long path recirc for cleanup.

Question 40

What happens to the plant if one FW pump is lost?

Answer 40

Rx power cutback will activate lowering power to the capacity of a single FW pump.

Question 41

What happens to the plant if at 100% power and both FW pumps trip?

Answer 41

The Rx would trip on low SG level and SG level would have to be maintained by aux feed.