EOP-TRIP-1 — Reactor Trip or Safety Injection
Purpose
Entry procedure for reactor trip or safety injection events. Provides immediate operator actions and diagnostic steps following a reactor trip, including verification of safeguard valve alignment and containment spray actuation status.
Key Actions / Information
Exam — 2019 Q49
EOP-TRIP-1 Step 1 Immediate Actions — manual reactor trip sequence (performed from memory, in order): FIRST actuate the Reactor Trip Switches (Pistol Grips), then the Trip Breaker BEZELS. If both fail, open Breakers E 6D and G 6D (MG set supply breakers). Trap: the Pistol Grips are FIRST, not the Bezels. The Bezels are the second option. Step 2.2 (Rod Insertion) is a subsequent immediate action, not the next step after trip failure.
Exam — 2023 Q1
Referenced for entry on manual reactor trip. Step 12 covers Safeguard Valve Alignment.
Exam — 2023 Q21
Used to assess containment spray actuation status.
Exam — 2023 Q83
Per AB.CR-0001, EOPs (including EOP-TRIP-1) are NOT applicable during Control Room Evacuation — they should be used for information only or as directed by the TSC.
Exam — 2023 Q87
EOP-TRIP-4 CAS directs actuate SI and return to EOP-TRIP-1 when PZR level cannot be maintained > 4% or subcooling reaches 0 degrees F. This is the correct transition — TRIP-4 does NOT direct entry into EOP-LOCA-1.
Exam -- 2023 Q93
Entry from CW malfunction: per AB.CW-0001, with 4 or more circulators out of service at ≥P-10 power, trip the reactor and enter EOP-TRIP-1.
Exam — 2020 Q55
Safeguard valve verification — Phase A isolation: CC113 and CC215 (Excess Letdown Component Cooling Valves) receive a Phase A signal to close. When verifying safeguards positions: CV2/CV277 (Letdown) do NOT close on Phase A (low PZR level only); CC131/CC190 (RCP Thermal Barrier) close on Phase B, not Phase A; BF13s close on Feedwater Isolation Signal, not Phase A.
Exam — 2022 Q3
Step 12, Safeguard Valve Alignment: check 2CC1 SAFEGUARDS ACTUATION Bezels — Red light LIT = train actuated, OUT = failed. On 2RP4, lights OUT = component failed to reposition. If any safeguards valve not in required position, place valves in safeguards position manually.
Exam — 2022 Q42
CS pump manual start requires SECs to be blocked/reset first. The SEC load sequencer overrides manual keyswitch control.
JPM — 2022 Sim-f
Step 9 — CNMT Spray/Phase B actuation during LBLOCA: containment pressure NOT < 15 psig → manually initiate Phase B and Spray using safeguards key switches on 2CC1. Alternate path: Phase B valves (2CC131, 2CC190) fail to auto-close and NaOH valves (2CS16, 2CS17) fail to auto-open on CS signal. Per Step 9.e, manually reposition valves to safeguards positions.
Scenario — 2022 #3
Manual reactor trip from AB.RCP-0001 (23 RCP motor bearing temp > 175 degF). During TRIP-1 immediate actions, main turbine fails to auto trip AND fails to manually trip (pistol grip and console pushbutton). MSLI fails to auto actuate. CT#1 (CT-12): RO manually initiates MSLI using Fast Close pushbuttons on 2CC2 before Red path to subcriticality or integrity CFST. Auto SI actuates (trips both SGFPs). 23 AFP fails to auto start — PO manually starts. Subsequently 22 AFP trips on overcurrent, 23 AFP trips on overspeed → loss of all AFW → CFST Heat Sink Red Path → transition to EOP-FRHS-1.
Step 19 — Immediate Actions for RTB Failure
Exam — 2018 Q49
EOP-TRIP-1 Immediate Actions when RTBs fail to open (after Trip Switches AND Bezels actuated): NEXT action is open Breakers E 6D and G 6D (MG set supply breakers), THEN actuate the TURBINE TRIP Switch. Trap: Rod Insertion and Main Steam Isolation are also part of immediate actions but come AFTER opening MG set breakers and turbine trip. The sequence is: Trip Switches → Bezels → MG set breakers → Turbine Trip → Rod Insertion → MSLI.
Exam — 2020 Q100
Step 20 of EOP-TRIP-1 specifically directs implementation of EOP-FRHS-1 when aux feed flow cannot be established. This is a procedure-directed transition that occurs BEFORE CFST monitoring begins at Step 30. Trap: do not wait for CFST monitoring (Step 30) to transition to FRHS-1 — EOP-TRIP-1 has a specific earlier step (Step 20) that directs the transition when all AFW is lost. Similarly, EOP-FRSM-1 has a specific transition before Step 30.
Scenario — 2022 #1
LBLOCA with auto SI failure on both trains (CT#1, CT-2): crew must manually actuate SI on at least one train before transition out of TRIP-1. Also, 22 RHR pump fails to start on SEC signal (CT#2, CT-5) — PO blocks and resets 2B SEC, RO manually starts 22 RHR. CAS actions: stop RCPs at <1350 psig, close charging mini-flows at <1500 psig. Transition to EOP-LOCA-1 based on containment pressure >4 psig.
Scenario — 2022 #4
Entered following manual reactor trip and SI on 23 SG tube rupture (650 gpm exceeding makeup). During TRIP-1 immediate actions: PO throttles AFW to no less than 22E4 lbm/hr. PO identifies 21 CFCU failed to start on SEC — blocks 2A SEC, resets, manually starts 21 CFCU in LOW speed. Feed side of ruptured SG isolated during TRIP-1 (23AF21, 23AF11 closed). Transition to SGTR-1 when 23 SG NR level rising uncontrolled. Note: 2PR7 PORV block valve already closed from earlier PORV leakage event — only 2PR6 block valve open.
Scenario — 2020 #1
Entered on LOOP with automatic reactor trip. Immediate actions completed — all 4KV Vital Buses found de-energized. Crew transitions to EOP-LOPA-1 based on all three vital buses de-energized.
Scenario — 2020 #2
Entered following manual Rx trip on RCS leak. Auto SI fails on both trains — RO manually actuates SI (CT-2). 22 RHR pump fails to start on SEC signal (21 RHR C/T) — PO blocks and resets 2B SEC, RO manually starts 22 RHR pump (CT-5). CAS actions: stop RCPs at <1350 psig, close charging mini-flows at <1500 psig. Containment pressure >15 psig — Phase B and Spray auto-initiate, MSLI auto-initiates. Transition to EOP-LOCA-1 based on containment pressure >4 psig.
Scenario — 2020 #3
ATWS — reactor fails to auto trip on 21 SG LVL LO-LO. RO trips reactor by opening both M-G set breakers 2E6D and 2G6D (CT-1). Auto SI actuates on containment pressure high. 21 SG faulted (large oscillating feed flow, no steam flow). RO manually initiates MSLI. 21BF13 fails to close — PO manually closes. Both RTBs fail to open — CRS directs WCC to locally open. Transition to EOP-LOSC-1 on 21 SG depressurizing in uncontrolled manner.
Exam — 2020 Q76
Step 17, CCW Pump Operation Evaluation: during MODE III (LBLOCA + LOOP), directs implementation of EOP-APPX-1 to start one CCW pump. Also directs S2.OP-SO.CC-0002(Q) for CCW HX operation, but that transition is only valid if ≥2 CCW pumps are in service and HXs are not in Auto. During MODE III SEC loading, no CCW pumps are running — so EOP-APPX-1 is the correct implementation, not SO.CC-0001 or SO.CC-0002.
Exam — 2018 Q98
ATWS at 4% power (reactor fails to trip on 21 SG LO-LO Level): IAW EOP-TRIP-1, the crew will MANUALLY insert control rods because at 4% power (turbine not online), automatic rod insertion will NOT exceed 48 steps/minute — the threshold in the basis document for allowing automatic insertion. Since the reactor is NOT tripped (all CR attempts failed), the crew will go to EOP-FRSM-1 (Response to Nuclear Power Generation). Trap: reactor power being less than 5% does NOT mean the reactor trip is confirmed — the TRIP-1 Step 2 criteria (power range NI <5%, IR dropping, IR startup rate negative) must ALL be met AT THE TIME the step is read by the NSS.
Scenario — 2018 #1
EOP-TRIP-1 entered after reactor trip from 22 RCP seal failure (seal leakoff >6 gpm). No SI required initially — crew transitions to EOP-TRIP-2. After 24 SG tube rupture develops, crew manually initiates SI and re-enters EOP-TRIP-1. During re-entry, 24BF13 (FW isolation valve) failed to close on SI/Phase A — PO manually closes from console. Then transitions to EOP-SGTR-1 when 24 SG NR level rising uncontrolled.
Scenario — 2018 #2
EOP-TRIP-1 entered after LBLOCA during orderly unit shutdown. Both trains of SI fail to auto-actuate; one keyswitch also fails to manually actuate. RO must use the other train keyswitch to initiate SI on both trains (CT#1: CT-2). During TRIP-1, 2B SEC fails to actuate — crew blocks, resets, and manually starts safeguards loads using Table A. Containment pressure >15 psig triggers Phase B and Spray actuation. Transitions to EOP-LOCA-1.
Connections
- Related systems: RPS/SSPS, ECCS, Containment Spray, Main Turbine, CCW
- Related procedures: S2.OP-AR.ZZ-0004 — Alarm Response Procedure, AB.CR-0001 — Control Room Evacuation, EOP-TRIP-4 — Natural Circulation, AB.CW-0001, OP-AA-101-111-1003 — Use of Procedures
- Related EOPs: EOP-FRSM-1 — Response to Nuclear Power Generation, EOP-FRHS-1 — Response to Loss of Secondary Heat Sink, EOP-APPX-1 — Component Cooling Water Restoration
- Related exam questions: 2018 Q49, 2018 Q68, 2018 Q98, 2019 Q48, 2019 Q49, 2020 Q1, 2020 Q16, 2020 Q18, 2020 Q55, 2020 Q56, 2020 Q75, 2020 Q76, 2020 Q100, 2022 Q3, 2022 Q42, 2023 Q1, 2023 Q21, 2023 Q83, 2023 Q87, 2023 Q88, 2023 Q93
- Related JPMs: 2018 JPM Sim-g, 2018 JPM Sim-h, 2022 JPM Sim-f, 2020 JPM Sim-e
- Related scenarios: 2018 Scenario 1, 2018 Scenario 2, 2019 Scenario 1 — Power Ascension / LOCA Outside Containment, 2019 Scenario 3 — ATWS / Stuck-Open PORV, 2019 Scenario 4 — SGFP Trip / Loss of Heat Sink, 2022 Scenario 1 — Load Reduction / LBLOCA, 2022 Scenario 3 — Power Ascension / Loss of Heat Sink, 2022 Scenario 4, 2020 Scenario 1 — Power Ascension / Station Blackout, 2020 Scenario 2 — Load Reduction / LBLOCA / Loss of Emergency Recirculation, 2020 Scenario 3 — ATWS / Feedwater Line Break, 2020 Scenario 4 — SGTR / PORV Failure, 2020 Scenario 5 — Loss of Heat Sink / Condensate Recovery
- Related exam: 2018 NRC Written Exam, 2018 NRC Operating Exam, 2019 NRC Written Exam, 2019 NRC Operating Exam, 2020 NRC Written Exam, 2022 NRC Written Exam, 2023 NRC Written Exam, 2022 NRC Operating Exam, 2020 NRC Operating Exam