CVCS Flashcards

1
Q

What are the CCP auto Starts?

A
  • SI (3 sec time delay on load shed)
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2
Q

What are the CCP Trips?

A
  • Loadshed - Train Specific
  • Overcurrent
  • Overload
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3
Q

What are the VCT Lvl auto actions?

A
  • 87% Full Divert to CVCSHUT (QLC-451/452)
  • 78% Divert starts to Open (QLC-452)
  • 24% Stops auto Makeup (QLC-451)
  • 14% Starts auto Makeup (QLC-451) (alarms)
  • 7% Low Lvl Alarm (QLC-452)
  • 2.5% RW Sequence (QLC-451/452)
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4
Q

What does QRV-301 (LD # Ctrl Valve) do and how does it fail?

A
  • Maintains backpressure (300-350#) on the LD orifices to keep the water from flashing to steam
  • Fails open
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5
Q

What does QRV-302 (Demin Divert Valve) do and how does it fail?

A
  • Diverts LD flow from demins to RC Filter if temp measured by QTS-301 is > 143°F ***
  • Fails to RC filter (Divert)
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6
Q

What does QRV-251 (CCP disch flow ctrl valve) do and how does it fail?

A
  • Ctrls CCP flow and is used to maintain Pzr Lvl
  • Position controlled by QFI-200 when in auto
  • Fails open
  • Has a minimum output of 23.5% (47gpm) while in auto *** (protect RCP seals)
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7
Q

What does QRV-200 (CCP header # ctrl valve) do and how does it fail?

A
  • Used to maintain required flow to RCP seals (32 gpm)

- Fails close

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8
Q

What does QLC-451 control for the VCT?

A
  • Make up **
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9
Q

What does QLC-452 control for the VCT?

A
  • Divert **
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10
Q

What does QRV-303 (Inlet Valve to VCT) do and how does it fail?

A
  • Diverts LD to CVCS HUTs if VCT lvl is too high

- fails flow to VCT

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11
Q

What will close/happen when Pzr is at 17% lvl on the CVCS System?

A
  • QRV-160/161/162 (LD orifice isolations) and QRV-111/112 (LD isolation valves)
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12
Q

When do QRV-160/161/162 (LD orifice isolations) auto close and how do they fail?

A
  • Close on Phase A
  • Close when either letdown isolation closed.
  • Close on loss of both CCPs
  • Close @ 17% Pzr Lvl
  • LD relief is AFTER the orifice isolations (SV-51) and reliefs at 600# to PRT ***
  • Fail Closed
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13
Q

What interlock is associated with QRV-111/112 (LD iso valves)?

A
  • Will not open if any QRV-160/161/162 (orifice isolation)is open
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14
Q

What happens on an SI in the CVCS System?

A
  • Both CCP auto start
  • IMO-910 and IMO-911 (RWST) open
  • ICM-250/251 and IMO-255/256 (BIT) open
  • QMO-451 and QMO-452 (VCT) close
  • QMO-200 and QMO-201 (to Regen Hx) close
  • QMO-225 and QMO-226 (CCP ELOs) close then cycle based on pressure (1812-1825#)
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15
Q

What happens on an Phase A in the CVCS System?

A
  • QRV-160/161/162 (orifice valves) close
  • QCR-300 and QCR-301 (Letdown isolation) close
  • QCM-250 and QCM-350 (RCP seal return) close
  • CCW to EXLD HX Closes
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16
Q

What happens on an RW Sequence in the CVCS System?

A
  • 2.5% lvl in VCT from BOTH QLC-451 and 452 ***

Auto Actions:

  • CCP suction from RWST Opens
  • When one of the suction valves from RWST is open, VCT outlet valves close
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17
Q

Will the BAT pump automatically shift to FAST speed during Emergency Boration?

A
  • No, it must be manually shifted to Fast Speed***
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18
Q

What are the CCP recirc valves (QMO-225/226) controlled by?

A
  • NPP-151/153 (Pzr #) ***
  • Valves will cycle 2 sec after a SI signal is received and maintain 1812-1825#
  • Valves will cycle until SI is reset and the switch is taken to Pull-to-Stop
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19
Q

Where do the CCP ELOs discharge to?

A
  • Downstream of the SW Return filter and upstream of the SW Return Hx
20
Q

Under what condition are the CCP ELOs manually closed?

A
  • Emergency boration to reduce time for boron to reach RCS
21
Q

What are the CVCS Demins used for?

A
  • Mixed bed removes fission and corrosion products
  • Cation removes lithium and provides pH control
  • Deborating demins reduce concentration of Boron when dilution is not practical at EOC life (good for about 50ppm boron each)
22
Q

What are the suction sources available to the CCPs?

A
  • VCT
  • RWST
  • SI suction line
  • RHR Hx Discharge
23
Q

Where does Emergency Boration and Alt Boration feed into?

A
  • CCP suction
24
Q

Where can seal water return discharge to?

A
  • Top of VCT

- CCP Suction downstream of VCT outlets

25
Q

What are the VCT pressure limits and basis?

A
  • Min VCT press 15# during RCP operations (for RCP seal #2 flow)
  • Max VCT press 37# (adequate Emergency Boration Flow)
26
Q

Describe purpose of the QRV-62 Charging valve bypass?

A
  • Spring loaded bypass check valve prevents over-pressurization of the charging lines
27
Q

Hydrogen is supplied to the Volume Control Tank (VCT).
This design feature of the CVCS system is provided to…

A. lower iodine levels in the RCS.
B. control the pH in the RCS.
C. increase demineralizer efficiency for corrosion products.
D. minimize oxygen in the RCS.

A
  • D. minimize oxygen in the RCS
28
Q

Which ONE of the following will occur if VCT level channel QLC-452 has failed HIGH? ASSUME no operator action is taken

a. QLC-451 will cause a backup divert.

b. Automatic makeup to the VCT will NOT initiate.

c. Charging pump suction will shift to the RWST at 1% actual level.

d. Actual VCT level decrease with potential charging pump damage.

A
  • d. Actual VCT level decrease with potential charging pump damage
29
Q

Unit 1 was operating at 100% power. The West CCP had been tagged out due to a bearing failure. The following sequence of events occurs:
- A reactor trip and safety injection occurs in response to a Steam - —– — Generator Tube Rupture.
- SI is reset.
- The T11D, 4kV AC ESF Bus subsequently loses normal power but is re-energized by the 1CD Emergency Diesel Generator.
T11D Automatic load sequencing is complete.

Which ONE of the following statements correctly describes the status the East CCP?
The East CCP …

A. has tripped and automatically restarted.

B. was NOT affected by the loss of Bus T11D.

C. has tripped and may be manually started immediately.

D. has tripped and may NOT be manually started until the load conservation signal resets.

A
  • C. has tripped and may be manually started immediately
30
Q

The plant has experienced a large break LOCA. The reactor has tripped and an SI signal is present. Charging Pumps Suction from RWST IMO-910 opened BUT IMO-911 failed to open.
Which ONE of the following is the impact of this action on the Charging Pump suction flow?

A. Both operating charging pumps will receive suction flow from the VCT.

B. Both operating charging pumps will receive suction flow from the RWST.

C. One charging pump will continue to take suction from the VCT and one charging pump will take suction from the RWST.

D. One charging pump will take suction from the RWST. The other charging pump will have no suction until operator action is taken.

A
  • B. Both operating charging pumps will receive suction flow from the RWST.
31
Q

When emergency boration is started by opening the emergency boration valve, QMO-410, the boric acid transfer pump:

a. will start automatically.

b. operating in slow speed will inject boron at a sufficient rate.

c. must be shifted to fast speed by the operator.

d. is shifted to fast speed automatically.

A
  • c. must be shifted to fast speed by the operator.
32
Q

Following the closure of Reactor Coolant Pump seal water return isolation valves, QCM-250 and -350, seal return flow will:

a. flow up through the seal number 2.

b. stop due to the closure of the valves.

c. flow through the thermal barrier to the RCS.

d. flow through a relief valve to the PRT.

A
  • d. flow through a relief valve to the PRT. (SV-50)
33
Q

The Technical Specification for Seal Injection Flow places limits on RCP seal injection flow resistance.

Which ONE of the following describes the reason for maintaining RCP seal injection flow resistance?

A. If the resistance is too small, ECCS injection flow may be less than required for core cooling during a small break LOCA.

B. If the resistance is too small, Auxiliary Spray flow may be less than required for RCS depressurization during a Steam Generator Tube Rupture.

C. If the resistance is too large, RCP seals may overheat during a large break LOCA.

D. If the resistance is too large, Charging Pump minimum flow may be less than required for pump cooling during a small break LOCA.

A
  • A. If the resistance is too small, ECCS injection flow may be less than required for core cooling during a small break LOCA.
34
Q

With 120 gpm letdown in service and blender controls in automatic on Unit 1, the VCT level transmitter QLC-452 fails to 100%.

With NO operator action, actual VCT level will …

A. Lower to zero and eventually result in loss of CCP suction.

B. Lower to 2.5% and RWST swapover will occur automatically.

C. Lower to 14% and stabilize due to auto makeup flow.

D. Rise to 87% and stabilize due to full divert flow.

A
  • A. Lower to zero and eventually result in loss of CCP suction.
35
Q

When Emergency Boration is started by opening the emergency boration valve, QMO-410, the boric acid transfer pump …

A. Will start automatically in slow speed to inject boron at a correct rate.

B. Will automatically shift to fast speed to inject boron at a correct rate.

C. Must be started in slow speed by the operator to inject boron at a correct rate.

D. Must be shifted to fast speed by the operator to inject boron at a correct rate.

A
  • D. Must be shifted to fast speed by the operator to inject boron at a correct rate.
36
Q

If either QRV-111/112 go closed, what will happen automatically?

A
  • QRV-160/161/162 are interlocked to auto close when QRV-111/112 go closed
37
Q

How many gallons per percent is the VCT?

A
  • 19gal/1%
38
Q

What has to happen first before QMO-451/452 will go closed?

A
  • IMO-910/911 (1/2) must be full open before QMO-451/452 will go closed
39
Q

If QRV-412 (PW to blender) is in auto, how much primary water flow is available? If its in manual?

A
  • 70 gpm (Auto)

- Adjustable (Manual)

40
Q

What would letdown pressure do if QRV-301 failed Open?

A
  • LD # would lower. May lower enough to cause flashing in LD line.
41
Q

What does QRV-500 (Deborator Divert valve) allow us to do?

A
  • Allows LD to be directed to RC Filter or to the Deborating Demineralizers if valved into service (Normally used when RCS is < 100 ppm boron).
  • Normally in the RC Filter position and placed to Debor. Demin. to perform boron removal of the RCS.(Dilution effect).
42
Q

If QLC-451 fails high, what will happen?

A
  • Trips QRV-303 to full divert

- Hi Lvl Alarm in VCT

43
Q

If QLC-451 fails Low, what will happen?

A
  • Auto Make-up will start
  • Low and low low Lvl Alarm
  • If switch isn’t in auto, that alarm will come in
44
Q

If QLC-452 fails high, what will happen?

A
  • Modulates QRV-303 to full open
45
Q

If QLC-452 fails Low, what will happen?

A
  • Low and low low lvl alarm will come in