Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Systems > Feedwater (FW) > Flashcards

Feedwater (FW) Flashcards

1
Q

What is the main purpose for the Feedwater system ?

A

-Provides Feedwater at proper pressure,temperature, & flowrate during all modes of operation
-Provide Recirc path back to Main Condenser for Feedwater cleanup during secondary startup & shutdown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What pressure do the Feedwater pumps discharge into the steam generators ?

A

Feedwater pumps raises condensate from 350psig to 1200psig to allow flow to go into steam generators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the Feedwater pump double suction arrangement provide for the pumps seals ?

A

Allows 350psig of suction pressure to be felt on pump shaft seals, rather than the 1200psig discharge pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is controls the Feedwater flow rate ?

A

-Flow is determined by speed of MFWP Turbine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the Digital Feedwater Control system do? How does it work ?

A

Controls Speed of MFWP turbine which is determined by Steam Generator water level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How much flow does each MFWP provide at power ?

A

Each pump delivers 62% of total required flow at rated power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where are the MFWP shaft seals receive seal water from ?

A

Supplied with seal water from Condensate Pump discharge header

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is instrument air supplied to MFWP bearing oil seals ?

A

-Keeps water out of seals
-Keep airborne particulate out of seals
-Prevents oil from leaking out of seals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What do the MFWP Mini-flow Recirc Control Valves do?

A

Maintain at least 5,000 gpm through the pump to prevent overheating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What determines the MFWP Miniflow Valves positions ?

A

It’s based on the flow rate going to the MFWP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the collar device used for on the MFWP Miniflow valve stems ?

A

Doesn’t allow valve to open all the way which limits flow through Miniflow valves limits to 5000gpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do the Mini-flow valves use ?

A

Reverse acting that is spring loaded to open & uses air to close the valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the Flow Transmitter do ? How does it work?

A

-Sense flow at suction of pump which sends electrical signal to Flow Indicating Controller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the Flow Indicating Controllers(FIC) do for the MFWP Miniflow valves ?

A

FIC receives signal from flow transmitter & then position a Flow Relay that controls air supply to Mini flow valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do the solenoid operated valves control air supply going to MFWP Mini-flow valves actuator ?

A

Solenoid Valve allows air to pass,stop it, or vent line to position mini flow based on detected flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What position are the Solenoid Valves normally in ?

A

Solenoid valves normally deenergize which allows air from Flow Relay to pass through mini-flow valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the MFWP Miniflow valve close & open ?

A

-When flow through pump is <5000gpm FIC positions Flow Relay to align valve to open mini flow valve to maintain at least 5000gpm to the ‘A’ Condenser
-Will close mini flow valve when flow rises above 5000gpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When does the MFWP Mini Flow Normally open ?

A

This happens when:
-MFWP discharge valve is closed
-Feedwater isolation valve closes
-Low power operations
-Following Reactor Trip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens on a low lube oil pressure to the Feedwater pump/ turbine ? How do the mini flow solenoid valves reposition ?

A

-The pump/turbine will trip
-Solenoid valve will supply air to top of valve and port air from bottom of it to CLOSE the Mini-Flow valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why does the MFWP Mini-Flow valve supposed to close, when there is low lube oil pressure to MFWP & pump trips ?

A

-Mini flow valve will close to prevent pump from freewheeling from condensate flow while pump is idle
-Don’t want freewheeling while there’s low lube oil pressure to protect bearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens to MFWP Mini-Flow on loss of instrument air ?

A

Mini flow valves fail OPEN on loss of instrument air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to mini flow valve on loss of 120VAC power from its MCC D-Panel ?

A

-Flow Indicating Controller will lose power, which makes FIC output go to ‘zero’
-Since it fails to “zero flow” it’ll make mini flow valve open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens on loss of 125VDC control power to the solenoid operated valves for mini flow valves during NORMAL OPERATION?

A

During normal operation nothing will happen since solenoid valves are normally deenergized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens on Feedwater pump trip due to loss of lube oil followed by loss of 125VDC to solenoid valves ?

A

-Loss of NK to solenoid valves fails to there normal deenergized state
-Since MFWP turbine is tripped FIC will sense low flow going through pump which will open mini flow valve
-This is bad for bearings during a low lube oil pressure trip

25
Q

Why is seal water used on MFWP ?

A

Used to stop Feedwater from leaking out of pump shaft & limit oxygen in leakage

26
Q

Where is the seal water supplied from? How are the pump seals protected from damage from foreign solids ?

A

-Supplied from condenser header
-2 y-strainers protect seals from damage (1strainer in service,other in standby)

27
Q

What do the Gland Seal Regulators do ?

A

DP Controllers send signal to these valves to maintain 20PSID across MFWP Pump seals

28
Q

How is the MFWP Seal Water directed into the pump ?

A

Flows along pump shaft to the leak off section in pump section

29
Q

What’re the two flow paths for the MFWP Seal Water leak off ?

A

-Seal water can exit pump via Gland Leak off piping & flows through Gland Leak-Off Regulator
-Some exits will drip out of pump shaft packing & is directed to Steam Packing Exhauster Drain Tank

30
Q

What do the Gland Leakoff Regulators do?

A

Pressure indicating controllers will sense Pump Gland Seal Discharge & will adjust these valves to maintain 135psig Gland Leakoff Back Pressure

31
Q

Where does the Seal Water exit to ?

A

Seal water will be sent to ‘A’ Main Condenser

32
Q

What’re the HPFWH used for ?

A

Preheat Feedwater to reduce thermal stress on the SGs & improve plant efficiency

33
Q

What’re the inlet and outlet temperatures for the HPFWH?

A

Inlet temperature to the #5HPFWH is 350F & outlet temperature from #7HPFWH is 450F

34
Q

How many HPFWH Strings are in service at a time ?

A

Both strings of HPFWH strings are normally in service with open inlet & outlet MOVs

35
Q

What is the HP Feedwater Train Bypass line used for ?

A

Bypass line supplies capability of operating with one HPFWH string out of service

36
Q

How does the HPFW Train Bypass line work ?

A

Normally maintained close, when opened passes 25% of total FW flow

37
Q

How foes 480VAC MCC (NH)binterface with the Feedwater system ?

A

480VAC provides power to Feedwater MOVs

38
Q

What does the 480VAC MCC DPanel provide power to ?

A

Provides 120VAC to MFWP Mini Flow Valve Flow Indicating Controllers

39
Q

How does 120VAC(NN) interface with Feedwater system ?

A

Provides power to Feedwater Pump Turbine Controller in SSR Room, which position Feedwater Pump Turbine Control Valves to regulate Feedwater Pump Speed

40
Q

How does the condensate system interface with the Feedwater system ?

A

-CD provides MFWP suctions
-CD provides water to pump seals via condensate header
-CD provides return path for Mini flow Recirc & long path Recirc
-CD provides exhaust & drain for:
FWP Turbine exhaust
FWP Turbine Drains
Steam line drains
Provides exhaust vacuum

41
Q

What happens to Feedwater system on loss NNN-D15 or D-16 ?

A

-Results in FWP Turbine Control Valves drifting close slowing down to 300rpm
-When this happens it WONT trip the pump it result in Reactor Power Cutback

42
Q

What will happen on loss of one Condensate Pump ?

A

-Will cause low suction pressure at ‘B’ MFWP, which will trip pump after 10seconds
-Once ‘B’ MFWP trips it’ll prevent, ‘A’ MFWP to not trip on low suction pressure

43
Q

What will happen on a loss of two condensate pumps ?

A

-Will cause low suction pressure on ‘B’ MFWP, trips after 10 seconds

-‘A’ MFWP suction pressure will rise,but not enough past low suction setpoint & will trip after 15 seconds

44
Q

How will loss of Extraction Steam & Drain affect Feedwater system ?

A

Loss of extraction steam to Feedwater heater would reduce thermal efficiency

45
Q

How does loss instrument air affect Feedwater system ?

A

-MFWP Mini-Flow Recirc will go open
Loss of service air to MFWP Bearing:
-Oil leak from bearing
-Airborne particulate entering bearing
-Allow water from Gland sealing steam packing exhaust drain tank

46
Q

What would happen on loss of Digital Feedwater Control System ?

A

Results inability to control Feedwater & loss of automatic MFWP speed control, could result in reactor trip to SG Low LVL

47
Q

During plant startup what operations do the condensate/Feedwater systems operate in ?

A

Placed in long path Recirc until water chemistry is right

48
Q

What must be in service prior to starting the Main Feedwater Pump?

A

Main Feedwater Pump Turbine must be placed in service by placing in Hot Standby per procedure

49
Q

When is the first Main Feedwater Pump started ?

A

Started prior to exceeding 3% power which is the capacity of one Aux. Feedwater Pump

50
Q

What happens to the Aux. Feedwater Pump when a Main Feedwater Pump pressurizes the Main Feedwater Line ?

A

Once main Feedwater pump is started the Aux. Feedwater Pumps are stopped

51
Q

When do the second Main Feedwater Pumps start ?

A

Plant operates with one pump up to 50% power, then 2nd pump is started

52
Q

What power level can one Main Feedwater Pump be shutdown at ?

A

If plant load decreases below 62%

53
Q

What does it mean when the Feedwater Pump & Turbine are in standby ?

A

Standby condition is maintained in warned & ready condition

54
Q

During plant shutdown when do the Feedwater pumps need to be stopped ?

A

-Stopped when the MFWP cause excess RCS cooling

55
Q

When does the Aux Feedwater Pump takeover during plant shutdown ?

A

Once MFWP cause excess RCS cooling, the Aux Feedwater Pump must be used to maintain SG Level

56
Q

After a shutdown what flow path is the Main Feedwater system placed in?

A

Main Feedwater system is placed in long path Recirc for shutdown chemistry control & system shutdown

57
Q

What happens on a loss of one MFWP ?

A

Reactor power cutback will initiate and reduce Reactor & Turbine power to the capacity of one MFWP

58
Q

What will happen on a loss of both MFWPs ?

A

Will trip reactor on low SG Level & SG Level will have to be maintain by Aux. Feedwater system

Systems (62 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions