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With the normal Standby Liquid Control tank level indicator out of service on Unit Two, the following is recorded:
Tank air gap is 76 inches
Temperature is 52°F
Concentration is 8.7%
The SLC system is currently:
A. Operable.
B. Inoperable, Figure 1 only is unacceptable.
C. Inoperable, Figure 2 only is unacceptable.
D. Inoperable, Figures 1 and 2 are both unacceptable.
B. Inoperable, Figure 1 only is unacceptable.
Tank volume with a 76" air gap is approx 2450 gallons using 20P-05, Figure 3. Using 2OP-05 Figure 1 minimum concentration with tank volume at or above 2450 gallons is 9.1%. Using 2OP-05, Figure 2, minimum concentration at 52°F is 8.5%. This makes SLC inoperable because concentration is too low based on tank volume (Figure 1).
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Unit Two has failed to scram. The operator places the SLC control switch to the Pump A & B Run position and observes the following:
SLC pump A red light is lit
SLC pump B red light is lit
SLC A squib valve continuity light is out
SLC B squib valve continuity light is lit
SLC pump discharge pressure is 1325 psig
Reactor pressure is 1150 psig
What is the status of SLC, and what operator action is required?
A. Squib valve A failed to fire, maintain two SLC pump operation.
B. Squib valve B failed to fire, maintain two SLC pump operation.
C. Squib valve A failed to fire, one SLC pump must be shutdown.
D. Squib valve B failed to fire, one SLC pump must be shutdown.
B. Squib valve B failed to fire, maintain two SLC pump operation.
OP-05, Section 5.2 directs operator to observe continuity lights out on initiation. Continuity light for squib valve B still lit indicates failure of squib valve B to fire. Per OP·05, the SLC pump discharge relief valve should not actuate with two pumps operating and only one squib valve open unless reactor pressure exceeds 1184 psig, which is possible during a ATWS even with 10 SRVs open. One pump must be shutdown only if RPV pressure is greater than 1184 psig.
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Unit 2 is at 94% power with no equipment out of service.
At 1315 on 07/20, annunciator A-04, 4-5, SQUIB VALVE CONTINUITY LOSS, is received.
The following conditions are observed by the Control Operator:
Squib Valve A Ready indicating light on P603 is OFF.
Squib Valve b Ready indicating light on P603 is ON.
SLC Pump 2A green light on P603 is ON.
SLC Pump 2B green light on P603 is ON.
I&C has determined that Squib Valve 2A, 2-C41-F004A, has a fault in its continuity monitoring circuit.
Which one of the following meets Technical Specification requirements?
A. Declare two SLC subsystems INOPERABLE and restore one SLC subsystem to OPERABLE status no later than 2115 on 07/20.
B. Declare one SLC subsystem INOPERABLE and restore at least one SLC subsystem to OPERABLE status no later than 1315 on 07/27.
C. Restore at least one SLC subsystem to OPERABLE status no later than 2115 on 07/20, otherwise be in MODE 3 no later than 0915 on 07/21.
D. Restore at least one SLC subsystem to OPERABLE status no later than 2115 on 07/20, otherwise be in MODE 3 no later than 1015 on 07/21.
B. Declare one SLC subsystem INOPERABLE and restore at least one SLC subsystem to OPERABLE status no later than 1315 on 07/27.
“A” is INOP per SR 3.0.1; can’t perform SR 3.1.7.4
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Unit 2 is operating at rated power when a loss of offsite power occurs; plant conditions are as follows:
Reactor Power 13%
Control Rods 105 not full in
DG4 Locked Out – Different Overcurrent
SLC Control Switch PUMP A RUN position
E7 – E8 Cross-Tie Breakers Racked IN
Which one of the following would be the response of the SLC system when the E7 – E8 Cross-Tie Breakers are closed?
SLC Squib Valve B:
A. fires, SLC pump B starts
B. does not fire, SLC pump B starts
C. fires, SLC pump B does NOT start
D. does not fire, SLC pump B does NOT start
C. fires, SLC pump B does NOT start
On an initiation signal both squib valves get a “fire”; but the pump does not start until the switch is moved.
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During an ATWS, SLC is initiated by placing the control switch to the PUMP A/PUMP B RUN position. /sqyub vakve B fails to fire and the operator places the ontrol swith to the PUMP A RUN position.
Two mnutes later, SLC pump A breaker trips (magnetic trip).
The operator should:
A. Perform alternate boron injection since neither squib valve is available.
B. Perform alternate boron injection since SLC pump B cannot be restarted.
C. Perform alternate boron injection since SLC pump B cannot inject through squib valve A.
D. Place the control switch to the PUMP B RUN position and inject boron using SLC pump B through squib valve A.
D. Place the control switch to the PUMP B RUN position and inject boron using SLC pump B through squib valve A.
Squib valve A is already fired and open. Either SLC pump can inject through either squib valve.
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Which one of the following methods is available to determine level in the SLC Tank following a loss of all air systems?
A. Direct the AO to valve in the local sight glass to obtain the level.
B. Have the AO read the level gauge on the local instrument rack.
C. Use the indication on the Level/Power Control ERFIS Screen.
D. Direct the AO to measure the distance from the surface of the liquid to the top of the SLC Tank.
D. Direct the AO to measure the distance from the surface of the liquid to the top of the SLC Tank.
- Without the instrument air system the level indicator will fail downscale, no dp to measure.
- The operating procedure has a section to determine the volume by measuring the air gap in the tank and comparing that to a graph to determine how much volume is left in the tank.
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