E-0 — Reactor Trip or Safety Injection¶
Entry procedure for any reactor trip or safety injection actuation.
Performs initial verification of automatic actions (reactor trip,
turbine trip, ESF actuations), confirms required equipment is running,
and diagnoses plant conditions to transition to the appropriate
event-specific EOP. CSF status trees are placed in service at event
entry and run independently throughout recovery.
CSF: subcriticality
CSF: core-cooling
CSF: heat-sink
CSF: rcs-integrity
CSF: containment
CSF: rcs-inventory
Step 1 verify-reactor-trip¶
Check: reactor trip breakers «TRIP-BKR-A» AND «TRIP-BKR-B» OPEN AND rod bottom lights LIT AND neutron flux «NIS-PR-AVG» decreasing
Caution: confirm subcriticality before any other action
- Verified → #verify-turbine-trip
Because: rapid neutron flux decrease confirms core shutdown
- Not verified → FR-S.1
Because: ATWS — must establish subcriticality before continuing diagnostic flow
Step 2 verify-turbine-trip¶
Check: all turbine stop valves CLOSED
Action: if not closed, manually trip turbine
- Verified or manually tripped → #verify-ac-buses
Step 3 verify-ac-buses¶
Check: at least one train of AC emergency buses «BUS-A-EMERG» / «BUS-B-EMERG» energized from offsite or onsite source (diesel generators «DG-A» / «DG-B»)
- At least one train energized → #check-si-status
- Both trains de-energized → ECA-0.0
Because: station blackout — natural circulation cooldown via TDAFW
Step 4 check-si-status¶
Check: SI actuation signal «SI-SIG» present (low pressurizer pressure «PT-455», high containment pressure «CTMT-PR», low steam line pressure, or manual)
Action: if SI required by symptoms but not actuated, manually actuate SI
- SI actuated (auto or manual) → #verify-si-pumps
- SI not actuated AND not required by symptoms → #check-rcp-status
Step 5 verify-si-pumps¶
Check: high-head SI pumps «SI-PUMP-A» / «SI-PUMP-B» running AND charging pumps «CHG-PUMP-A» / «CHG-PUMP-B» in SI alignment AND boric acid flow path established
Action: if any pump not running, manually start and align suction
- All running, flow established → #verify-phase-a-isolation
- No SI flow despite pumps running → FR-C.1
Because: ECCS flow blockage requires immediate inadequate-core-cooling response
Step 6 verify-phase-a-isolation¶
Check: Phase A containment isolation complete (containment ventilation isolated, sample lines closed, non-essential penetrations isolated)
Action: if not complete, manually initiate Phase A
- Complete or manually initiated → #verify-msl-isolation
Step 7 verify-msl-isolation¶
Check: if MSLI signal was generated, all MSIVs CLOSED
Action: if MSLI signal present and any MSIV open, manually close affected MSIV
Caution: an MSIV that will not close on demand is a strong indicator of a faulted SG; flag for diagnostic at step 15
- No MSLI signal generated → #verify-feedwater-isolation
- MSLI signal AND all MSIVs closed (or manually closed) → #verify-feedwater-isolation
- MSLI signal AND MSIV will not close → #verify-feedwater-isolation
Because: continue diagnostic; faulted-SG isolation will be addressed in step 15
Step 8 verify-feedwater-isolation¶
Check: main feedwater isolation valves CLOSED on all SGs (if FWI signal present)
Action: if not isolated, manually isolate main feedwater
- Isolated or manually closed → #verify-afw
Step 9 verify-afw¶
Check: AFW pumps «AFW-PUMP-A» / «AFW-PUMP-B» / turbine-driven «AFW-PUMP-T» running AND AFW flow established to at least one intact SG
- AFW flow ≥ minimum on at least one SG → #check-ecc-flow
- No AFW flow on any SG → FR-H.1
Because: loss of secondary heat sink — bleed-and-feed required
Step 10 check-ecc-flow¶
Check: ECCS flow indications consistent with running pumps (high-head, intermediate-head, accumulators armed, RHR aligned for low-head)
Action: if flow anomaly, investigate alignment
- Flows nominal or alignment corrected → #check-rcp-status
- Cannot resolve flow anomaly → FR-C.1
Step 11 check-rcp-status¶
Check: RCS pressure «PT-455» AND subcooling margin «SUB-MARGIN» AND SI status to determine RCP trip criteria
Caution: tripping RCPs while RCS is voiding may interrupt natural circulation flow path
Within: 60 seconds of recognizing voiding conditions — RCP seal damage accumulates rapidly under low subcooling
Action: if SI active AND subcooling margin «SUB-MARGIN» < 30 °F, trip all RCPs
- SI active AND RCPs tripped per criterion → #check-phase-b
Because: prevents RCP damage from voided suction and loss of seal cooling
- SI active AND subcooling margin ≥ 30 °F → #check-phase-b
Because: positive subcooling means no voiding at the RCP suction
- SI not active → #check-phase-b
Step 12 check-phase-b¶
Check: containment pressure «CTMT-PR» compared to Phase B setpoint «PHASE-B-SIG»
Within: 10 seconds of containment pressure exceeding Phase B setpoint — automatic actuation should occur but manual backup is time-critical
Action: if above Phase B setpoint and any function not verified, manually initiate Phase B isolation and containment spray pumps «CSPRAY-A» / «CSPRAY-B»
- Below Phase B setpoint → #check-pzr-relief
- Above Phase B setpoint AND Phase B isolation complete AND containment spray running → #check-pzr-relief
- Containment pressure rising rapidly → FR-Z.1
Because: rapidly rising containment pressure may indicate a LOCA inside containment or compromised heat sink
Step 13 check-pzr-relief¶
Check: pressurizer PORVs «PORV-456A» / «PORV-456B» CLOSED AND block valves «BLOCK-456A» / «BLOCK-456B» available; pressurizer safety valves NOT lifting
Action: if any PORV stuck open and block valve available, close block valve
- All relief valves closed (or block valve closed on stuck PORV) → #check-sg-levels
- Stuck-open relief, block valve will not close → E-1
Because: stuck-open relief with no isolation is a small LOCA — manage via E-1
Step 14 check-sg-levels¶
Check: each SG narrow-range level — «SG-A-LVL-NR», «SG-B-LVL-NR», «SG-C-LVL-NR», «SG-D-LVL-NR»
Action: if any SG level dropping below low setpoint, verify AFW alignment to that SG
- All SGs in nominal post-trip band → #check-faulted-sg
- Any SG level uncontrollably rising → #check-faulted-sg
Because: rising level is a candidate symptom for SGTR — flag for diagnosis at step 16
- Any SG level dropping below setpoint with AFW recoverable → #check-faulted-sg
Step 15 check-faulted-sg¶
Check: any SG showing rapidly decreasing pressure OR high steam line radiation OR steam line break indications
- No faulted SG indications → #check-sgtr
- One SG faulted (pressure dropping fast) → E-2
Because: faulted-SG isolation prevents excessive RCS cooldown
- All SGs depressurizing simultaneously → ECA-2.1
Because: uncontrolled multiple-SG depressurization — likely main steam header break
Step 16 check-sgtr¶
Check: any SG showing rising level uncontrolled OR high secondary-side radiation («SG-A-N16», «SG-B-N16», «SG-C-N16», «SG-D-N16») OR primary-to-secondary leak indications
- No SGTR indications → #check-rcs-conditions
- SGTR confirmed → E-3
Because: ruptured SG inventory loss requires identification, isolation, and cooldown to terminate leak
Step 17 check-rcs-conditions¶
Check: RCS pressure trend, pressurizer level, subcooling margin, hot-leg temperatures
Note: this step is the central diagnostic — symptoms here decide LOCA vs. stable post-trip
- RCS pressure decreasing AND containment pressure or sump level rising → E-1
Because: LOCA — inventory loss to containment, requires SI continuation and recirculation planning
- RCS pressure stable, subcooling adequate, no LOCA/SGTR/faulted-SG indications → ES-0.1
Because: stable post-trip conditions — recover via reactor-trip-response procedure
- RCS conditions ambiguous OR multiple symptom sets present → ES-0.0
Because: rediagnosis procedure with expanded symptom evaluation
- All cross-page transitions handled → #monitor-csfs
Step 18 monitor-csfs¶
Note: CSF status trees were placed in service at event entry and continue to monitor independently of the active EOP
Caution: a RED or ORANGE CSF status overrides the active EOP; respond to the CSF function-restoration procedure when challenged
- Continue per active EOP → END
Tags¶
-
id: TRIP-BKR-A
description: reactor trip breaker A position
sim-path: rps.trip_breaker.a.position
units: enum[OPEN,CLOSED]
equipment: reactor-protection-system
source: Vogtle UFSAR §7.2 -
id: TRIP-BKR-B
description: reactor trip breaker B position
sim-path: rps.trip_breaker.b.position
units: enum[OPEN,CLOSED]
equipment: reactor-protection-system
source: Vogtle UFSAR §7.2 -
id: NIS-PR-AVG
description: nuclear instrumentation power-range average (4-channel)
sim-path: nis.power_range.avg
units: percent
equipment: nuclear-instrumentation
source: Vogtle UFSAR §7.7 -
id: BUS-A-EMERG
description: emergency 4kV bus A energization status
sim-path: electrical.bus.emerg_a.energized
units: bool
equipment: bus-a-emerg
source: Vogtle UFSAR §8.3 -
id: BUS-B-EMERG
description: emergency 4kV bus B energization status
sim-path: electrical.bus.emerg_b.energized
units: bool
equipment: bus-b-emerg
source: Vogtle UFSAR §8.3 -
id: DG-A
description: emergency diesel generator A status
sim-path: electrical.dg.a.status
units: enum[STOPPED,STARTING,RUNNING,LOADED,FAULT]
equipment: emergency-dg-a
source: Vogtle UFSAR §8.3.1.1 -
id: DG-B
description: emergency diesel generator B status
sim-path: electrical.dg.b.status
units: enum[STOPPED,STARTING,RUNNING,LOADED,FAULT]
equipment: emergency-dg-b
source: Vogtle UFSAR §8.3.1.1 -
id: SI-SIG
description: safety injection actuation signal (latched)
sim-path: ess.si.actuation_signal
units: bool
equipment: si-system
source: Vogtle UFSAR §6.3 -
id: PT-455
description: pressurizer pressure (wide range)
sim-path: rcs.pressurizer.pressure_wr
units: psig
equipment: pressurizer
source: Vogtle UFSAR §5.4
range: [0, 3000] -
id: CTMT-PR
description: containment building pressure
sim-path: containment.pressure
units: psig
equipment: containment
source: Vogtle UFSAR §6.2 -
id: SI-PUMP-A
description: high-head SI pump A status
sim-path: ess.si_pump.a.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: si-system
source: Vogtle UFSAR §6.3 -
id: SI-PUMP-B
description: high-head SI pump B status
sim-path: ess.si_pump.b.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: si-system
source: Vogtle UFSAR §6.3 -
id: CHG-PUMP-A
description: charging pump A status
sim-path: cvcs.charging_pump.a.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: charging-system
source: Vogtle UFSAR §9.3.4 -
id: CHG-PUMP-B
description: charging pump B status
sim-path: cvcs.charging_pump.b.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: charging-system
source: Vogtle UFSAR §9.3.4 -
id: AFW-PUMP-A
description: motor-driven AFW pump A status
sim-path: afw.pump.a.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: afw-system
source: Vogtle UFSAR §10.4.9 -
id: AFW-PUMP-B
description: motor-driven AFW pump B status
sim-path: afw.pump.b.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: afw-system
source: Vogtle UFSAR §10.4.9 -
id: AFW-PUMP-T
description: turbine-driven AFW pump status
sim-path: afw.pump.tdafw.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: afw-system
source: Vogtle UFSAR §10.4.9 -
id: PHASE-B-SIG
description: containment Phase B isolation signal (latched)
sim-path: ess.phase_b.actuation_signal
units: bool
equipment: containment
source: Vogtle UFSAR §6.2 -
id: CSPRAY-A
description: containment spray pump A status
sim-path: ess.cspray_pump.a.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: containment-spray
source: Vogtle UFSAR §6.2.2 -
id: CSPRAY-B
description: containment spray pump B status
sim-path: ess.cspray_pump.b.status
units: enum[STOPPED,RUNNING,FAULT]
equipment: containment-spray
source: Vogtle UFSAR §6.2.2 -
id: PORV-456A
description: pressurizer PORV 456A position
sim-path: rcs.pressurizer.porv.456a.position
units: enum[OPEN,CLOSED,INTERMEDIATE]
equipment: pressurizer
source: Vogtle UFSAR §5.4 -
id: PORV-456B
description: pressurizer PORV 456B position
sim-path: rcs.pressurizer.porv.456b.position
units: enum[OPEN,CLOSED,INTERMEDIATE]
equipment: pressurizer
source: Vogtle UFSAR §5.4 -
id: BLOCK-456A
description: pressurizer PORV 456A block valve position
sim-path: rcs.pressurizer.block.456a.position
units: enum[OPEN,CLOSED]
equipment: pressurizer
source: Vogtle UFSAR §5.4 -
id: BLOCK-456B
description: pressurizer PORV 456B block valve position
sim-path: rcs.pressurizer.block.456b.position
units: enum[OPEN,CLOSED]
equipment: pressurizer
source: Vogtle UFSAR §5.4 -
id: SG-A-LVL-NR
description: SG-A narrow-range level
sim-path: secondary.sg.a.level_nr
units: percent
equipment: sg-a
source: Vogtle UFSAR §10.3 -
id: SG-B-LVL-NR
description: SG-B narrow-range level
sim-path: secondary.sg.b.level_nr
units: percent
equipment: sg-b
source: Vogtle UFSAR §10.3 -
id: SG-C-LVL-NR
description: SG-C narrow-range level
sim-path: secondary.sg.c.level_nr
units: percent
equipment: sg-c
source: Vogtle UFSAR §10.3 -
id: SG-D-LVL-NR
description: SG-D narrow-range level
sim-path: secondary.sg.d.level_nr
units: percent
equipment: sg-d
source: Vogtle UFSAR §10.3 -
id: SG-A-N16
description: SG-A main steam line N-16 radiation monitor
sim-path: rad.msl.a.n16
units: cps
equipment: sg-a-msl
source: Vogtle UFSAR §11.5 -
id: SG-B-N16
description: SG-B main steam line N-16 radiation monitor
sim-path: rad.msl.b.n16
units: cps
equipment: sg-b-msl
source: Vogtle UFSAR §11.5 -
id: SG-C-N16
description: SG-C main steam line N-16 radiation monitor
sim-path: rad.msl.c.n16
units: cps
equipment: sg-c-msl
source: Vogtle UFSAR §11.5 -
id: SG-D-N16
description: SG-D main steam line N-16 radiation monitor
sim-path: rad.msl.d.n16
units: cps
equipment: sg-d-msl
source: Vogtle UFSAR §11.5 - id: SUB-MARGIN
description: RCS subcooling margin (T_sat at PT-455 minus hot-leg temperature)
sim-path: rcs.subcooling_margin
units: degF
equipment: rcs
source: Vogtle UFSAR §15.6 (RCP-trip subcooling threshold; nominal 30 °F)