Advanced Systems > Shutdown Cooling > Flashcards

Shutdown Cooling Flashcards

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1
Q

LCO 3.4.7 “PCS Loops - Mode 5, Loops Filled” requirement

A

1 SDC train shall be operable and in operation with >= 2810 gpm flow through the reactor core and either 1 additional SDC train shall be operable, or the secondary side water level of each S/G shall be >= -84%

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2
Q

LCO 3.4.7 “PCS Loops - Mode 5, Loops Filled” applicability

A

Mode 5 with PCS loops filled

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3
Q

LCO 3.4.7 “PCS Loops - Mode 5, Loops Filled” required action if 1 SDC train inoperable and any S/G with secondary side water level not within limit

A

IMMEDIATELY initiate action to restore a second SDC train to operable or initiate action to restore S/G secondary side water levels to within limits

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4
Q

LCO 3.4.7 “PCS Loops - Mode 5, Loops Filled” required action if 2 SDC trains inoperable or SDC flow through the core not within limits

A

IMMEDIATELY suspend all operations involving reduction in PCS boron concentration, and initiate action to restore 1 SDC train to operable and in operation with >= 2810 gpm flow through the reactor core

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5
Q

LCO 3.4.8 “PCS Loops - Mode 5, Loops Not Filled” requirement

A

2 SDC trains shall be operable and either 1 SDC train in operation with >= 2810 gpm flow through the reactor core, or 1 SDC train in operation with >= 650 gpm flow through the reactor core with 2 of the 3 charging pumps incapable of reducing the boron concentration in the PCS below the minimum value necessary to maintain the required shutdown margin

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6
Q

LCO 3.4.8 “PCS Loops - Mode 5, Loops Not Filled” applicability

A

Mode 5 with PCS loops not filled

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7
Q

LCO 3.4.8 “PCS Loops - Mode 5, Loops Not Filled” required action if 1 SDC train inoperable

A

IMMEDIATELY initiate action to restore SDC train to operable

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8
Q

LCO 3.4.8 “PCS Loops - Mode 5, Loops Not Filled” required action if 2 SDC trains inoperable, or SDC flow through the core not within limits

A

IMMEDIATELY suspend all operations involving reduction of PCS boron concentration, and initiate action to restore 1 SDC train to operable status and in operation with SDC flow through the reactor core within limit

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9
Q

LCO 3.9.4 “Shutdown Cooling (SDC) and Coolant Circulation - High Water Level” requirement

A

1 SDC train shall be operable and in operation

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10
Q

LCO 3.9.4 “Shutdown Cooling (SDC) and Coolant Circulation - High Water Level” applicability

A

Mode 6 with the refueling cavity water level >= 647 ft elevation

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11
Q

LCO 3.9.4 “Shutdown Cooling (SDC) and Coolant Circulation - High Water Level” required action if 1 required SDC train inoperable or not in operation

A

IMMEDIATELY initiate action to restore SDC train to operable status and in operation, and suspend operations involving a reduction in PCS boron concentration, and suspend loading irradiated fuel assemblies in the core

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12
Q

LCO 3.9.5 “Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level” requirement

A

2 SDC trains shall be operable, and 1 SDC train shall be in operation

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13
Q

LCO 3.9.5 “Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level” applicability

A

Mode 6 with the refueling cavity water level < 647 ft elevation

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14
Q

LCO 3.9.5 “Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level” required action if 1 SDC train inoperable

A

IMMEDIATELY initiate action to restore SDC train to operable, or initiate action to establish the refueling cavity water level >= 647 ft elevation

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15
Q

LCO 3.9.5 “Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level” required action if no SDC train operable or in operation

A

IMMEDIATELY suspend operations involving a reduction in PCS boron concentration, and initiate action to restore 1 SDC train to operable and in operation, and initiate action to close all containment penetrations providing direct access from containment atmosphere to outside atmosphere

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16
Q

What is the purpose/function of the SDC system?

A
  • Removes decay heat from the PCS

- Cools PCS from 300 F to refueling temperature, 130 F, with a CCW temperature of 90 F

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17
Q

What is the SDC operational design pressure and temperature?

A

270 psia, 300 F

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18
Q

How are SDC from PCS MOVs, MO-3015 and MO-3016 operated?

A
  • 1 switch in Control Room, 1 switch on C-33
  • Switches are in parallel, so either switch will open/close the valve
  • Switches have a seal in circuit, and spring return to neutral. Operate switch in open or closed direction, release switch, and valve will stroke fully to that position.
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19
Q

What is the interlock associated with opening SDC from PCS MOVs, MO-3015 and MO-3016?

A

PCS < 275 psia (admin limit of 265 psia) to protect SDC piping from overpressure

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20
Q

What are the power supplies for the SDC from PCS MOVs, MO-3015 and MO-3016?

A

MO-3015 - MCC-1

MO-3016 - MCC-2

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21
Q

What is the normal position of the SDC from PCS MOVs, MO-3015 and MO-3016 while at power?

A

Closed with the breaker open

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22
Q

What is the purpose/function of RV-0401, SDC from PCS Relief Valve?

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A
  • Located between MO-3015 and MO-3016 to protect the piping between the valves when they are closed, and the water between the valves heats up.
  • Relieves to PSDT at 2485 psig
23
Q

What is the purpose/function of RV-3164, SDC Suction Relief Valve?

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A
  • Protects SDC suction piping from overpressure

- Relieves to the Quench Tank at 300 psig

24
Q

What is a precaution if the PCS is pressurized, and MO-3015/3016 are open?

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A

At least one of MO-3015 or 3016 have to have power in order to isolate RV-3164 to prevent an unisolable PCS leak.

25
Where can CV-3055, SDC HX Inlet, be operated from?
Control Room or C-33. Switches are in parallel, so if either switch is in the OPEN position, then the valve can't be closed.
26
What is the motive force for operating CV-3055, SDC HX Inlet?
- HP air | - Can be operated manually locally
27
How does CV-3055, SDC HX Inlet, fail on a loss of air?
As is
28
What is the normal position of CV-3055, SDC HX Inlet?
Electrically locked closed
29
Where can CV-3212, 3213, 3223, and 3224, SDC HX Isolation Valves, be operated from?
Control Room or C-33. Switches are in parallel, so if either switch is placed in the CLOSE position, valve can't be opened.
30
What is the motive force for operating CV-3212, 3213, 3223, and 3224, SDC HX Isolation Valves?
HP air
31
How do CV-3212, 3213, 3223, and 3224, SDC HX Isolation Valves, fail on a loss of air?
As is
32
What is the normal position of CV-3212, 3213, 3223, and 3224, SDC HX Isolation Valves?
Electrically locked open
33
How is CV-3025, SDC Temperature Control Valve, operated?
HIC-3025A in Control Room and HIC-3025B on C-33. Controllers are in series. HIC-3025A is operated in manual. Operator sets the output signal, which is sent to HIC-3025B on C-33. HIC-3025B is operated in auto, and sends the signal received from HIC-3025A to the valve.
34
What is the power supply for HIC-3025A?
Y-01
35
How does CV-3025, SDC Temperature Control Valve, fail on a loss of air?
Closed
36
How does CV-3025, SDC Temperature Control Valve, fail on a loss of Y-01?
Causes a 0% output signal, which causes the valve to go closed.
37
What is the normal position of CV-3025, SDC Temperature Control Valve?
Electrically locked closed
38
How is CV-3006, SDC HXs Bypass, operated?
FIC-0306 in the Control Room, and HIC-0306 on C-33. Controllers are in series. FIC-0306 is operated in manual. Operator sets the output signal, which is sent to HIC-0306 on C-33. HIC-0306 is operated in auto, and sends the signal received from FIC-0306 to the valve.
39
What is the power supply for FIC-0306?
Y-01
40
How does CV-3006, SDC HXs Bypass, fail on a loss of air?
Open
41
How does CV-3006, SDC HXs Bypass, fail on a loss of Y-01?
Causes a 0% output signal, which causes the valve to go open.
42
What is the normal position of CV-3006, SDC HXs Bypass?
Normally air is isolated to fail the valve open. This ensures operability of the LPSI system.
43
What is the function of CV-3006, SDC HXs Bypass?
Valve works in conjunction with CV-3025, SDC Temperature Control Valve, to direct flow through and around the SDC HX to control cooldown rate and total SDC flow.
44
What is the purpose/function of RV-402 and RV-0403, SDC HX Tube Side Relief Valves?
Protects the tube side of the SDC HX from overpressure. Valves relieve at 500 psig to the WESG Sump.
45
What is required for overpressure protection while SDC is in service?
-LTOP in service in SDC mode of operation (310 psia lift setpoint, 265 psia pre-trip alarm) OR -PCS vented via a vent path able to relieve 167 gpm at a PCS pressure of 315 psia
46
What precaution must be taken to prevent steam binding of SDC equipment?
Ensure 25 F of subcooling when PCS temperature > 185 F.
47
What is the limitation on operating LPSI Pumps when placing SDC in operation for warmup?
Only start 1 LPSI Pump, because only 1 LPSI Loop Injection Valve will be throttled open to about 170 gpm, which is the minimum flow requirement for a LPSI Pump.
48
What PCS level is considered reduced inventory?
623' 0"
49
What precautions/limitations apply when in reduced inventory?
- Both SDC trains operable - Y-01 operable, including both feeds from MCC-1 and MCC-2 and the auto transfer switch to reduce the chance of losing SDC. - Don't swap LPSI pumps unless directed by ONP-17, due to the possibility of air binding the pump.
50
What is the danger when operating in solid plant operations?
Can overpressurize SDC system, because a 1 F change in temperature is equivalent to a 100 psi pressure change.
51
What is the potential consequence of isolating the SDC system with temperature > 210 F?
Could result in steam binding of the SI pumps, and potentially severe water hammer.
52
What is a precaution associated with PCS temperature monitoring when all PCPs are stopped?
SDC return temperature must be used to determine PCS cold leg temperature due to lack of forced circulation mixing. PCS pressure and SDC return temperature must be monitored closely to prevent exceeding heatup and cooldown limits, and prevent overpressure.
53
What are the limits for the length of time SDC can be secured?
May be secured for up to 1 hour, or the time it takes for a 20 F heatup, whichever is shorter.
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