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LOIT 2020 exam prep > Exam 10 prep > Flashcards

Exam 10 prep Flashcards

SBCS, BOP ESFAS, Instrument Air

1
Q

What is the capacity of the SBCS?

Include each valve, what group it is and what shell they go to.

A
  • Capacity:
    • Can handle 56% Turbine Load Rejection W/O RPCB
    • ~ 7% per valve
  • SBCV 1001
    • 0-25% Master controller output
    • Group X valve
    • Goes to “A” Shell
  • SBCV 1004
    • 25-50% Master controller output
    • Group X valve
    • Goes to “B” Shell
  • SBCV 1003
    • 50-66.7% Master controller output
    • Group X Valve
    • Goes to “A” Shell
  • SBCV 1006
    • 50-66.7% Master controller output
    • Group X Valve
    • Goes to “C” Shell
  • SBCV 1002
    • 66.7-83.3% Master controller output
    • Group Y Valve
    • Goes to “A” Shell
  • SBCV 1005
    • 66.7-83.3% Master controller output
    • Group Y Valve
    • Goes to “B” Shell
  • SBCV 1007 & 1008
    • 83.3%-100% Master controller output
    • Group “Y” Valves
    • Both go to Atmosphere
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2
Q

What are the power supplies to SBCS?

A
  • NNN-D11 & NNN-D12
    • Upon a Loss of Power to either one, the valves fail close. This is due to losing logic power supplies
    • Cannot be operated in Manual or Auto
  • NKN-D42

Powers the solenoid valves that supply air to the valves. They fail closed on a loss of NKN-D42

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3
Q

How does a loss of IA affect SBCS?

A
  • Loss of IA
    • @ < 80 psig SBCVs FAIL CLOSED
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4
Q

How does the master controller come back from a loss of power?

A
  • System Restoration Following Loss of Power
    • The master controller will be in MAN with 0% output.
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5
Q

How does a loss of vacuum affect SBCS?

How is the system restored from this condition?

A
  • Loss of Vaccum
    • @ 5.5” HgA ON 2 OUT OF 3 LOGIC
    • In this condition 1007 & 1008 are still available due to going to atmosphere.
  • When vacuum is restored OPERATORS MUST MANUALLY RESTORE THE SYSTEM TO SERVICE BY:
    • Taking the switch to RESET on B06 OR
    • Depressing the EMERGECY OFF CONDENSER INTERLOCK RESET on the SBCS cabinet
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6
Q

State the function to SBCS that PT-1027 provides.

A
  • PT-1027
    • PERMISSIVE
    • If this fails low then a manual permissive can be inserted to allow the modulate to work in auto
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7
Q

State the function to SBCS that PT-1024 provides

A
  • PT-1024
    • MODULATE
    • Generates the modulate signal. If this fails then the system must be controlled manually
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8
Q

What does Modulate do in the SBCS system?

How is the modulate setpoint biased?

What is the controlling parameter?

A
  • Modulate Compares the following:
  • Setpoint:
    • Generated by taking Steam Flow for SG 1 for a baseline setpoint.
      • Must know that 1170 psig is the baseline pressure @ 0% Steam Load (Flow)
      • Then it subtracts a BIAS to this setpoint based on 100X (PZR PT)
        • UP TO 50 PSIG
        • As Pressure goes up then the setpoint goes down
        • @ 2250 psig BIAS is zero. Anything less than 2250 psig there will be no BIAS
        • Only BIAS is >2250 psig (.2 psi change per 1 psi above 2250 psi)
  • Controlling Parameter
    • PT-1024 compared to the setpoint generated above and will build in a modulate demand based on deviation from setpoint
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9
Q

What does Permissive do in the SBCS system?

How is it biased?

What is the controlling parameter?

A

Permissive Compares the following

  • Setpoint
    • Generated by taking Steam flow for SG 2 as a baseline setpoint
      • -20 psi from modulate (so permissive should come in first) must know that normal permissive is 1150 psig is the baseline pressure @ 0% Steam Load (Flow)
      • Then it subtracts a BIAS to this setpoint based on 100Y (PZR PT)
        • UP TO 50 PSIG
        • As Pressure goes up then the setpoint goes down
        • @ 2250 psig BIAS is zero. Anything less than 2250 psig there will be no BIAS
        • Only BIAS is >2250 psig (.2 psi change per 1 psi above 2250 psi)
  • Controlling Parameter
    • PT-1027 compared to the setpoint generated above and will build in a IN or OUT permissive for all valves.
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10
Q

How is SBCS master controller cycled between R and L?

A
  • Must have the Master controller in Manual when cycling between R/A and L/A
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11
Q

Is there a quick open feature if the master controller is not in R/A?

Is there a quick open feature for any individual valve that is not in auto?

A
  • There is no Quick Open feature if the master controller is not in R/A
  • There is no Quick Open feature for valves that are not in Auto
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12
Q

What must be present at the valve level to operate them in Local Auto?

A
  • Operating Valves in Local Auto
    • INDIVIDUAL VALVE CONTROLLERS MUST HAVE MANUAL PERMISSIVE IN
      • If you were to not have a manual permissive on the valves then no matter what master controller output is the valve will not open. (Unless the entire system permissive is in)
      • Only one bypass valve at a time should have a manual permissive when in Local Auto
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13
Q

Why is the permissive signal sealed in for 15 sec?

A
  • Permissive signals seal in for 15 SECS.
    • Ensures permissive signal is present until demand has decayed away to prevent a quick close of valves
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14
Q

How does a failed HI Ppzr(PT-100X) affect the SBCS permissive setpoint?

A
  • If you have a failed HI 100X PT then you could end up “riding” on the permissive
    • Because the modulate demand setpoint < permissive setpoint the master controller output builds up to 100% and then when the permissive finally comes in ALL VALVES WILL FULL OPEN for 15 SECS and then FULL CLOSE
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15
Q

How does the master controller tracking behave during a quick open event?

A
  • During a Quick Open Master Controller setpoint goes to 83.3%. This allows for ease of transition will the Quick Open is over. Unless there is a QOB on Rx Trip or MFP Trip.
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16
Q

What actuates a Quick Open?

What will block a Quick Open?

A
  • Quick Open/Quick Open Block
    • X1, Y1, RPCB-1
      • 100X PZR PT going up with SG 1 Flow going down (Rate of change for both)
    • X2, Y2, RPCB-2
      • 100Y PZR PT going up with TLI going down (Rate of change for both)
    • Must have all of the above occurring to actually get a Quick Open
    • Quick Open Block
      • Everything blocked on Loss of FWP
      • GRP-Y blocked on Rx Trip
      • GRP-X blocked on Rx Trip w/ < 573.5F Tavg
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17
Q

How is an AMI generated from SBCS?

A
  • AMI
    • Control Channel power <15% (From RRS)
    • TLI < 15% and Reactor Power < threshold demand:
      • Threshold demand is the lesser of:
        • The setpoint selected by the Operator on B05
        • Or TLI & SBCS Availability (~7% per valve)
18
Q

What are the power supplies to BOP ESFAS?

How does a loss of power affect BOP ESFAS?

A
  • Power Supplies
    • Auctioneered PK/PN
    • Each cabinet has 2 cooling fans powered from each source
    • Loss of PN
      • On a loss of either PN the associated train Rad Monitors lose power and cause the following actuations on BOTH TRAINS due to cross trips:
        • CREFAS
        • FBEVAS
        • CPIAS
19
Q

What will actuate a CREFAS?

What actions take place on a CREFAS signal?

Will CREFAS stop the CR normal AHU?

A
  • CREFAS
    • High activity on RU-29 (A train) OR RU-30 (B train) automatically initiates a CREFAS
    • FBEVAS and CPIAS CROSS TRIPS CREFAS
    • CREFAS CROSS TRIPS NOTHING BUT CREFAS
    • Component Actuations:
      • Closes normal intake dampers
      • Opens essential OUTSIDE intake dampers
      • Starts BOTH CT Pumps
      • Starts CR Essential AHU
      • Starts ALL Essentials (except DG)
    • CREFAS WILL NOT stop the Control Room Normal AHU
      • The fan for this AHU will turn off when EITHER HJA-M01 or HJB-M01 fully close which will happen on either CREFAS signal
20
Q

What will actuate a FBEVAS?

What actions will occur on a FBEVAS actuation?

A
  • FBEVAS
    • High activity on RU-31 (A train) OR RU-145 (B train) automatically initiates a FBEVAS
    • Component Initiates:
      • Closes normal supply and exhaust dampers,
      • Stops normal fans and
      • Starts essential AHUs aligned to the fuel building
      • ‘B’ Train FBEVAS, ONLY the Fuel Bldg Normal Fans will still be running.
21
Q

When will a cross trip occur on a FBEVAS actuation?

A
  • On an AUTO actuation ONLY the FBEVAS for that train will CROSS TRIP the other train FBEVAS and both CREFAS trains
    • Manual Actuations from B05 WILL NOT cause cross trips!
      • This is important because if you manually initiate “B” FBEVAS ONLY, the normal AHUs WILL NOT STOP and must be manually secured to prevent deadheading.
    • The TEST pushbutton WILL cause cross trips
  • If a SIAS and FBEVAS happen concurrently SIAS will win and automatically align suction to the Aux Building. This can be overridden.
22
Q

What will actuate a CPIAS?

What actions will occur on a CPIAS?

A
  • CPIAS
    • High activity on RU-37 (A train) OR RU-38 (B train) automatically initiates a CPIAS
    • This trips a CREFAS; does not cross trip anything else other than the other CPIAS
    • Only isolates dampers no equipment started
    • Damper interlocks turn off the blowers (Refuel Purge & Power Access Purge)
23
Q

What will actuate a CRVIAS?

What actions occur on a CRVIAS?

A
  • CRVIAS
    • NO RU Monitors. NO cross Trips.
    • MANUAL Actuation ONLY (B05 or BOP-ESFAS Cabinets)
    • CRVIAS overrides the Outside Air Damper signal from SIAS or CREFAS and closes OSA dampers.
    • Starts CT pumps
    • Starts all essentials other than DG
24
Q

How does the BYPASS keyswitch work on BOP ESFAS?

Can you get a BYPASSED module in an ACTUATED state?

A
  • The BYPASS only bypasses the instrument used to automatically initiate the signal.
    • If one train is already in BYPASS and the other train is taken to BYPASS BOTH trips are removed from BYPASS
  • YES! A bypassed channel’s module can still get a cross trip from the other train, or from FBEVAS, CPIAS cross trips, or from manual initiation from B05.
25
Q

What will cause a LOP/LS?

How will a loss of a potential transformer affect the LOP/LS instrumentation?

What happens on a LOP/LS actuation?

A
  • LOP/LS Signals
    • 2 out of 4 logic is required.
    • Loss of a single PT will cause an actuation of a degraded and loss of voltage relay
      • This will not cause a LOP signal as same transformer fed relays will not cause an actuation even though there is 2 of them.
    • Upon receipt of the LOP:
      • 1 sec Load Shed Pulse to prevent overloading the DG
      • LOP signal seals itself in for 60 SECS after the bus is re-energized
      • Automatically starts sequencing on loads depending on the sequencer mode
26
Q

On the LOP/LS module, how does Keylock bypass work?

A
  • Keylock Bypass
    • Each channel (4 for each cabinet) has a keylock.
    • You cannot bypass the same channel on both cabinets.
      • This will remove both channels from bypass
27
Q

In what mode is the DG started from teh DGSS module and how is it swapped?

A
  • DGSS
    • The DGSS module only starts the DG in TEST Mode
      • An actual actuation signal from BOP-ESFAS is required to switch the DG to emergency mode
28
Q

What are the ways to start the DG from the DGSS module?

A
  • LOP
  • SIAS/CIAS
  • AFAS-1
  • AFAS-2
  • Do not get this confused with actually testing the actual actuation signals. This is only related to the DGSS. If the actual modules were depressed the DG would start in Emergency Mode and the Sequencer would sequence on loads
29
Q

What will happen if the DG is started from the DGSS and the the test signal isnt removed?

A
  • Remember if started from the DGSS and the signal isn’t taken away a TEST Mode trip will try and trip the DG but it will get down to 280 RPM air will be continuously applied since the start signal is still there and it will bleed down the air reservoirs.
30
Q

What does the sequencer do with regard to large vs small loads?

A
  • Only starts LARGE loads SMALL loads like valves are actuated from PPS ESFAS
31
Q

Describe the 5 modes of BOP ESFAS.

How does the sequencer change modes?

A
  • Mode 0: STANDBY. Must be in this mode for weekly auto-testing
  • Mode 1: SIAS/CSAS w/ NO LOP
  • Mode 2: SIAS/CSAS w/ LOP
  • Mode 3: LOP only
  • Mode 4: Everything else
  • When modes are changed the sequencer goes back through 0
    • When a mode change happens it WILL NOT secure previously running loads it will simply start the newly required loads
32
Q

Why is it important to wait 60 seconds after re energizing BOP ESFAS before resetting equipment?

A
  • Upon re-energization of BOP-ESFAS you must wait 60 seconds after re-energization before resetting equipment to prevent spurious actuations while the spurious LOP signal clears.
33
Q

How will BOP ESFAS handle a loss of power with one train in bypass?

A
  • If a train is in bypass and the other train loses power THEN the train in bypass will come out of bypass and ACTUATE (possibly).
34
Q

READ THE OIM FOR LIGHT - ACTUACTION QUESTIONS

A
35
Q

Describe the operating characteristics of IAA-UV-2 and how it fails on a LOP/LOA

What signal will auto close IAA-UV-2

A
  • IAA-UV-2 is a solenoid valve powered from PKA that fails closed and supplies instrument air to containment.
    • Auto closes on CSAS
36
Q

When does the low IA header pressure alarm actuate?

What provides a backup to IA at ~ 85 psig?

A
  • Low IA header pressure
    • Alarm @ 95 psig
    • N2 backup valve to IA opens @ 85 psig
37
Q

Describe the operating characteristics associated with the IA compressors.

A
  • When compressors are started they run unloaded for 20seconds to minimize starting current
    • Normal loaded amps: 150 amps
    • Normal unloaded amps: 75-90 amps
    • Heat of compression raises IA temp to ~ 95F above ambient
38
Q

What provides cooling water to the IA compressors?

How is a TC outage conducted with the IA compressors?

A
  • TC supplies cooling water to air compressors
    • Except during the outage where DS can be supplied to 1 compressor at a time via temp hoses
39
Q

What is the purpose of the Separator?

A
  • Compressor discharges high pressure/ high temperature oil/air mixture to the Separator
    • Separator Tank pressure PROVIDES THE MOTIVE FORCE for the oil to circulate through the system
40
Q

How does the IA compressor sequencer work to control IA pressure?

A
  • IA Compressor Sequencer
    • PC-265 will control IA header pressure to a target of 114 psig within a 10 psig band (109-119 psig)
    • @ 109 psig and going down the sequencer starts next compressor.
    • @ 119 psig it will unload compressors in sequence

LOIT 2020 exam prep (12 decks)

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