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Systems > Extraction Stea & Drains(ED) > Flashcards

Extraction Stea & Drains(ED) Flashcards

1
Q

What does the Heater Drain Tank provide for the Extraction Steam system ?

A

-Ultimate drain point for most of the normal drains in ED system
-Provides suction source for the HTR Drain Pumps

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2
Q

Where does the HTR Drain Pumps discharge to ?

A

-Discharges to suction of the associated Main FW Pump

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3
Q

How is flow regulated to the Main FW Pump suction ?

A

-Regulated by HTR Drain Tank level to ensure it has enough water for HTR Drain Pump
-Mini flow back to HTR Drain Tank is provided for each HTR Drain Pump

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4
Q

How many HTR Drain Pumps are there? Where do they take suction from ?

A

There are two HTR Drain Pumps, that have there own HTR Drain Tank to take suction from

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5
Q

What powers the HTR Drain Pumps ?

A

-NBN-S01 powers ‘B’ HTR Drain Pump
-NBN-S02 powers ‘A’ HTR Drain Pump
THINK OPPOSITE

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6
Q

Where is seal water provided from for HTR Drain Pumps ?

A

Provided from Condensate Header at 375-500psig

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7
Q

Where is cooling water for the HTR Drain Pumps stuffing box provide from ?

A

Provided from condensate service header at 50-100psig

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8
Q

What is the HTR Drain Pump mini follow valve positioned by ?

A

Positioned by HTR Drain Pump flow transmitter to maintain minimum flow through HTR Drain Pump

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9
Q

What happens to the HTR Drain Pump mini flow valve when unit comes up in power & has more extraction steam flow available to pump ?

A

Mini flow valve will close

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10
Q

When will stop the HTR Drain Pumps ?

A

-HTR Drain Tank LO-LO level alarm
-HTR Drain Pump low flow after time delay
-Electrical protection

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11
Q

Where does flow from the HTR Drain Tank go when the High Level Control Valve actuates ?

A

Directs high energy fluid to condenser

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12
Q

Why is it bad for flow from the HTR Drain Tank High Level Control Valves to actuate ?

A

It’s bad on the tube because it causes high vibration & erosion in tube bundle due to velocity & thermal changes when entering condenser

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13
Q

What just be done to minimize high level control valve to be activated ?

A

Reducing power to 50% until HTR Drain Trains are cross-tied

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14
Q

Why is having a cross connected HTR Drain Pump important , when a High Level Control Valve actuates ?

A

Reduce HTR Drain Tanks High Level Control Valve actuation <25%

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15
Q

How many HP Feedwater Heaters trains are there ?

A

-There are two parallel trains of HPFWH

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16
Q

Why does the #5 HPFWH not have a level control system ?

A

It doesn’t contain a drain cooler region

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17
Q

Where does the #5 HPFWH directly drain too ?

A

Drains to HTR Drain Tank

18
Q

How many trains of LPFWH are there ?

A

There are three LPFWH trains in parallel

19
Q

What stages of the LP Turbine do the LPFWH receive extraction steam from ?

A

Receives extraction steam from stages 8,9,11,12

20
Q

How is the LPFWH sub cooling zone or drain cooler water level maintained ?

A

Maintained by Normal Level Control Valve

21
Q

What’re the bleeder trip valves used for ?

A

-Used during turbine trip to prevent overspeed on a turbine trip

22
Q

How do the bleeder trip valves work ?

A

-Closes automatically when steam flow stops or has reverse flow during turbine trip
-Has pneumatic cylinders that uses spring force to help close valve when air is bled off

23
Q

What is the balance arm device used for on the bleeder trip valves ?

A

It helps open valve with minimum differential steam pressure

24
Q

Why does the bleeder trip valve pneumatic Cylindrical device equipped with three-way test valve ?

A

-Equalizes air pressure across operator cylinder to partial close valve by the spring force
-This will cause DP to go up across valve which shows the valve isn’t stuck open

25
Q

Why does the #4 LPFWH have two Bleeder Trip Valves on its extraction steam lines ?

A

Has enough energy to cause overspeed trip by itself

26
Q

Which valves in the ED system are reverse acting ?

A

-All the High Level Control Valves AND #1 LPFWH NORMAL level control valve are Reverse-Acting

27
Q

Which valves in the ED system are direct acting ?

A

-2-7 LPFWH normal level control valves
-1st & 2nd stage reheated drain tanks normal level control valves

28
Q

Where does the ED system drain to on a loss of instrument air ?

A

Will drain to the Main Condenser

29
Q

How does the heaters normal or high level control valves operate ?

A

They operate water level within pipe stack that will send out output air signal to valve position

30
Q

What’s the procedure categories for placing a sight glass in/out of service ?

A

-1st &2nd Stage Reheater Drain Tanks
-Moisture Separator Drain Tank
-Fw Heater
-HTR Drain Tank

31
Q

What automatically happens to HPFWH during a HI-HI level ?

A

-Isolates extraction steam supply valve
-Closes normal control valve
-Open extraction steam line drain valve to condenser
-1st&2nd Reheater Drain Tank vent line will isolate from the affected heater

32
Q

What will automatically happen during a LPFWH HI-HI Level ?

A

-Entire LP train will be isolated by heater drain isolation valves
-Isolates extraction steam to #3 & #4 heaters
-Opens extraction line solenoid operated drain valve for #3 & #4 heaters

33
Q

Which level control valves are used during low power operations for the LP & HP Heaters ?

A

High level control valves will open because insufficient DP

34
Q

When coming up in power how long are the Moisture Separator Drain Tank & First Stage Reheater Drain Tank directing flow to Main Condenser ?

A

Until Turbine Generator 10% loaded

35
Q

What happens to Moisture separator Drain Tank & 1st stage Reheater drain Tank when turbine load reaches 10%?

A

-High Level Control valves will close
-Normal Level Control valves will OPEN

36
Q

What happens to 2nd Stage Reheater Drain Tank when turbine load reaches 20% ?

A

-High level control valve goes closed
-Normal Level Control Valve goes open

37
Q

When are the HTR Drain Pumps starting when coming up in power ?

A

-When power reaches 25% the first HTR Drain Pump starts preferable on same side as FW Pump
-2nd HTR Drain Pump can be started 30-40%

38
Q

When do the HTR Drain Pumps stop ?

A

-1st HTR Drain Pump will stop at 40%
-2nd HTR Drain Pump will stop at 25%

39
Q

If power operation with only one HTR Drain Pump why just precautions be taken ?

A

Must be taken to limit vibration & erosion in condenser tube bundle due to high energy fluid to condenser

40
Q

What happens to HTR Drain Pumps Discharge Valve on loss of Instrument Air ?

A

Discharge valve will fail closed & Recirc valve will fail open
-Putting pump in full Recirculation

Systems (62 decks)

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