Loss of Class Inst power Flashcards
State the exit criteria necessary to leave the Loss of class instr and ctrl power PK/PN AOP.
State any Rx trip criteria included in this AOP.
Power restored and all applicable steps performed.
OR
Power cannot be restored and a plant shutdown in progress.
Rx trip criteria:
RDT level ≥ 75% or ≥ 5 psig and unable to restore level or pressure
PKA is lost (cannot restore seal bleed off to VCT)
PKB is lost and unable to locally open CHB-UV-505 (seal bleed off CIV)
State the indications of a PK or PN failure.
PK: affected voltmeter indicates 0 volts.
125V IE CC M– CHGR X/XX PNL D– TRBL
PN: LEDs are off on various CPCs or class instr reading offscale for the affected channel.
120 VAC IE PNL D – INVERTER X TRBL
How would a loss of PKA-D21 or PKB-D22 affect DG operation?
PKA-D21 A DG / PKB-D22 B DG
- DG controls, starting circuit and electrical protection are lost
- Cannot be started (test or emergency)
- DG trips (if running)
- DG output breaker loses control power (reverse power if paralleled to off-site)
- AO will locally open breaker if in parallel
Why are all of the affected PPS channel trip bistables bypassed on a loss of PN?
Necessary because the loss of power to all respective channels input parameter instruments will give a TRIP condition on all parameters of that channel. They will fail LOW and are considered INOPERABLE.
Now reduces margin to trip.
Bypass portion of the system STILL HAS POWER.
How would a loss of PN or PK affected the AFW system?
Loss of PKA-M41/PKA-D21
- AFA governor control power lost.
- Trips on overspeed if running. (PKA-D21 only)
- AFA Steam Supply MOVs Fail as is.
- Steam supply MOVs may automatically open when power is restored.
- Locally trip AFA to prevent an overspeed trip from occuring
- AFA FCVs fail as is (AFA-32 & 37).
- AFN loses DC control power (PKA-D21 only)
- Swap control power to alternate (A battery charger)
- Downcomer isolations (172 / 175) fail open and VPI is lost
Loss of PKB-M42/PKB-D22.
- AFB pump loses DC control power
- Downcomer isolations (130 / 135) fail open and VPI is lost.
Loss of PKC-M43:
- AFC-33 and AFC-36 (AFA FCVs) fail as-is
Why is it necessary to trip AFA-P01 on a loss of PKA?
On restoration of power, the steam supply valves may automatically open.
How are ADVs and MSIVs/FWIVs affected by a loss of PK and or PN?
ADVs
- Any PK lost: two ADVs failed closed (permissive lost)
- PNA or PNB lost: two ADVs failed closed (controller lost)
- Not affected by PNC or PND
MSIVs / FWIVs
- Controller power normally aligned directly from the battery.
- Alternate source is from PKA-M41/PKB-M42.
- Valves would fast close if power was lost.
How does a loss of PK affect PPCS and PLCS?
Loss of PKA or PKB
- Loss of one Aux Spray valve (FSVs)
- PKA only: loss of Main Spray due to IA CIV failing closed (PKA is worse, only have ONE aux spray valve)
- Control Power lost to one Class Back-up Heater (could be operated locally)
- Control Power lost to one or two Charging Pumps (Depending on E pump alignment)
- Letdown is lost (CIV fails closed)
- PZR level would be rising uncontrolled (and pressure) until AO can stop charging pump(s) locally.
- Loss of Letdown AOP and Loss of IA AOP will also be performed.
How would a loss of PN affect PPCS or PLCS?
Loss of PNA or PNB
- PZR LT-100X or 100Y fails low (Charging pumps, letdown flow, and PZR heaters affected if selected)
- AOP actions will select the good instrument
How would a loss of PK or PN affect the BOP-ESFAS system?
Each BOP-ESFAS cabinet (A/B) powered from both PK and PN (A and B).
- Power is auctioneered in the cabinet.
- Loss of one power supply: BOP-ESFAS remains functional
Loss of PNA or PNB:
- Power lost to associated rad monitors
- CREFAS, (29, 30), CPIAS(37, 38), and FBEVAS(31, 145) automatically actuate
If all power lost to a cabinet and the cabinet is re-energized, a load shed and sequencing would occur.
- Disable associated equipment to prevent load shed and sequencing prior to restoring power (refer to 40OP-9SA02).
What would happen to the BOP ESFAS cabinet if power is lost and subesquently reenergized?
A load shed will occur with loads sequencing back on. Action is taken to disable that train’s equipment to prevent load shedding from occurring.
How does a loss of PNC or PND affect the CEDMCS system?
PNC-D27 (Pac-Man)
- A and C RTBs open (loss of power to RPS)
- CEDMCS cabinet C5 loses power
- False UEL, LEL, and Rod Bottom Lights (75%) on Operators Module, Core Mimic for CEA #1 and CPC’s A, B, C target rods.
- Subgroup Logic prevents CEA motion for all subgroups in AS, MS, and MG.
- Can only move unaffected CEAs in MI.
- Pulse counters zeroed for all CEAs with Rod Bottom Lights lit.
PND-D28 (Anti Pac-Man)
- B and D RTBs open (loss of power to RPS)
- CEDMCS cabinet C6 loses power
- False UEL, LEL, and Rod Bottom Lights (25%) on Operators Module and Core Mimic for the CPC D target rods.
- Subgroup Logic prevents CEA motion for all subgroups in AS, MS, and MG.
- Can only move unaffected CEAs in MI.
- Pulse counters zeroed for all CEAs with Rod Bottom Lights lit.
How does a loss of PNA or PNB affect CEDMCS?
PNA-D25 or PNB-D26
- Two RTBs open (PNA (A and C) or PNB (B and D)) due to loss of power to RPS logic.
- CEAC 1 lost in all CPC Channels inoperable due to the loss of power to RSPT 1.
How does a loss of PNC or PND affect CEACs and CPCs?
- CEAC 2 lost
- CEAC 1 indication is the only available CEA position indication.
- CEAC 1 visible on CEAPD or CPCs.
- SPTAs require emergency boration because only one CEA position can be verified.
- Since only one CEA position indicator channel is OPERABLE for more than one CEA per CEA Group; there is no LCO condition, therefore LCO 3.0.3 entry is required.
How does a loss of PK or PN affect RPS and PPS ESFAS?
Loss of PN:
- Bypass all associated PPS Channel trip bistables that are NOT bypassed on another channel.
- PPS Bypass system remains functional even though lights will not be lit. It has an auctioneered power supply.
- PPS bistable comparator cards have a loss of signal trip circuit. All associated functions are tripped.
- If input signal is disconnected to any parameter, that parameter will trip. (senses no voltage)
- VOPT and Log Power trip due to loss of power to the Excore NI
- CPC (DNBR/LPD) trip due to the CPC losing power
- Three of the six matrices lose half of their power.
- Causes RTBs A and C OR B and D to trip open.
- SPLA trip impacted and opens associated RTB.
- CEAC 1 (PN A or B) or CEAC 2 (PN C or D) in all CPC channels are inoperable due to loss of power to RSPTs and may generate penalty factors when re-energized.
Loss of PK:
- Associated channel RTB opens (loss of control power to UV coil)
