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ILOT > Circ Water > Flashcards

Circ Water Flashcards

1
Q

What are the Circ water pump trips?

A

Motor Differential O/C
Bus O/C or Differential O/C
Discharge Valve Closed (20 sec TD)

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2
Q

What can cause a Circ water pump inop light?

A

No control power to breaker
Breaker in PTL
Breaker not in operate
Springs not charged
Loss of trip coil continuity

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3
Q

What logic is enforced when the Circ water stop enable light is in?

A

4 pumps running - to stop the 1st
pump its d/ch vlv must be closed to the mid position

≤ 3 pumps running - all running pump d/ch valves must be mid pos. AND stopped must be closed

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4
Q

What are the Recirc runbacks associated with the circ water system?

A

Intermediate (45%) – Loss of 1 CW pump (4 init) and vacuum > 4.5”HgA
Full (30%) – Loss of 1 CW pump (2 or 3 init) and vacuum > 5.8”HgA

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5
Q

What interlocks associated with the circ water start enable light are required to start the first circ water pump?

A

Control in MCR (NOT in Remote) and Discharge Valve 100% Closed

at least 2/6 pairs of condenser inlet and outlet valves must be fully open

NOTE: When starting the first CW pump there is a 20 second time delay between the pushing of the START PB and when the pump actually starts. This time delay allows the lube water storage tank to provide lubricating water and clear the lube water low flow interlock prior to the pump running.

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6
Q

What interlocks associated with the circ water start enable light are required to start the second circ water pump?

A

Control in MCR (NOT in Remote) and Discharge Valve 100% Closed

at least 3/6 pairs of condenser inlet and outlet valves must be fully open, AND the discharge valve of the running CW pump must be open to the MID position or more

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7
Q

What interlocks associated with the circ water start enable light are required to start the third/fourth circ water pump?

A

Control in MCR (NOT in Remote) and Discharge Valve 100% Closed

at least 3/6 pairs of condenser inlet and outlet valves must be fully open, AND the discharge valve of the running CW pumps must be open to the MID position or more, AND Cooling Tower Bypass Valve HV-2173 must be fully closed.

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8
Q

What occurs on an emergency trip of a CW pump?

A

PB control will trip the CW pump irrespective of the pump stop permissive signals. The discharge valve on the tripped pump will fully close and ALL running CW pump discharge valves will close to the MID position.
IF a single CW pump is running when the EMERG TRIP PB is depressed, the pump will trip and the discharge valve will fail as is.

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9
Q

What are the power supplies to the CW pumps and their discharge valves?

A

10A501 - A/C pumps
10A502 - B/D pumps
10A502->10B502 - A/C discharge valves
10A501->10A503 - B/D discharge valves

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10
Q

Can you open a circ water discharge valve without meeting the interlocks?

A

Yes, if the OPEN INTLK OVRD/RESET is pressed as well

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11
Q

What is the logic associated with stopping a circ water pump?

A

To stop the first pump when four pumps are running, the associated pump discharge valve must be closed to the MID position.

To stop a pump when < 4 pumps are running, ALL running CW pump discharge valves must be closed to the MID position AND the discharge valve of ALL stopped CW pumps must be fully closed.

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12
Q

Once the logic is met to stop a circ water pump, what are you indications and what actions must you take?

A

The ENABLE light will be lit and by depressing the stop pushbutton the discharge valve will fully close and the associated pump will trip

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13
Q

How do the cooling tower bypass valves operate when depressing the open pushbutton?

A

This PB opens the Cooling Tower Bypass Valve when control is not in REMOTE and
<2 CW pumps are running.

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14
Q

Under what conditions can the CT basin makeup valves be closed?

A

EITHER Makeup to River or Makeup to Intake structure vavles must be fully open to permit the CT basin makeup valve to be closed

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15
Q

Under what conditions will the Turbine Building CW sump pumps trip?

A

trips/isolate on high rad

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16
Q

What trips are associated with the Condenser dewatering pumps?

A

low suction pressure (6.5psig)

17
Q

What provides makeup water to the cooling tower?

A

SW provides 30,000gpm makeup to cooling tower. Only about 13,600 gpm are consumed by evaporation and drift.

18
Q

What happens when the CW pump fuses are removed?

A

Removing CW pump fuses makes Bailey think the pump is running. Reinserting the fuses makes Bailey thinks the pump tripped (this causes running valve pumps to go to mid position)

19
Q

What changes in operations are required during winter operations with reference to the CW system?

A

During winter ops, if you are inside the “Close Valves” zone on the graph, you then monitor for ice buildup. If you get greater than 1 foot of ice, then you close the valves.

20
Q

Under what conditions are the Condensor outlet valves permitted to close?

A

THROTTLE PERMIT illuminated - valve control is not in REMOTE and the outlet valve is >2% open

valve control is not in REMOTE and ANY of the following conditions exist:
* ALL CW pumps are stopped
* 4/6 inlet/outlet valve pairs are fully open
* 3/6 inlet/outlet valve pairs are fully open when only 1 CW pump is running

21
Q

Under what conditions are the Condensor inlet valves permitted to close?

A

CLOSE PERMIT - Illuminates when control is not in REMOTE and ANY of the following conditions exist:
* ALL CW pumps are stopped
* > 4/6 inlet/outlet valve pairs are fully open
* > 3/6 inlet/outlet valve pairs are fully open when only 1 CW pump is running.

22
Q

Under what conditions are the Condensor inlet valves permitted to open?

A

OPEN PERMIT - Illuminates when control is not in REMOTE and the associated condenser outlet valve is >2% open

23
Q

What 3 conditions will allow the CW pump discharge valves to open?

A
  • At least 3 CW pumps running and their discharge valves at MID position
  • “OPEN INTLK OVRD” selected
  • ALL pumps stopped
24
Q

What components in the CW system are operated from the Control Panel?

A

CW Pumps
D/Ch Valves
Cond In/Out Vlvs
CT Bypass Vlvs
CT Deicing Vlv
Header Vent Vlv

25
Q

What components in the CW system are operated locally?

A

Lube Water Valve
Intake Structure Deicing Vl
CT M/U Bypass to River
CT M/U Bypass to SWIS
CT basin M/U valve
Cond. Waterbox Vent/Drn

26
Q

How is the loss of 10A501 different from a loss of 10A502?

A

Loss of 10A501: The ‘A’ and ‘C’ CW pumps will trip and their d/ch valves will close (‘B’ and ‘D’ vlvs will remain as is). Vice-versa for 10A502 loss. Remember that the 10B502/503 busses can be x tied via their 480v USS.

27
Q

What happens upon the restoration of power to the CW pump discharge valves?

A

If the lost bus is subsequently returned, the two remaining discharge valves will go to their MID position since only 2 pumps are running.

28
Q

What must you do when removing a circ water pump from service?

A

if it will result in condenser backpressure exceeding 5” HgA then the main turbine operation procedure should be reviewed for operating limitations

ILOT (93 decks)

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