Q76 — PZR Vapor Space Leak ECCS Status and Procedure Transition
T1G1 APE 8 AA2.15 (3.9)
Given:
- Salem Unit 2 experienced an automatic reactor trip and Safety Injection due to lowering RCS pressure
- The crew suspects a PZR vapor space leak
Then:
- The crew is implementing 2-EOP-LOCA-1, Loss of Reactor or Secondary Coolant
- Subcooling is 10 degrees F
- RCS pressure is 1450 psig and stable
- PZR level is 30% and rising
Based on the above conditions, which of the following completes both statements?
1. Which ECCS Pump(s) is/are injecting?
2. Per 2-EOP-LOCA-1, what procedure will the CRS direct NEXT?
- Salem Unit 2 experienced an automatic reactor trip and Safety Injection due to lowering RCS pressure
- The crew suspects a PZR vapor space leak
Then:
- The crew is implementing 2-EOP-LOCA-1, Loss of Reactor or Secondary Coolant
- Subcooling is 10 degrees F
- RCS pressure is 1450 psig and stable
- PZR level is 30% and rising
Based on the above conditions, which of the following completes both statements?
1. Which ECCS Pump(s) is/are injecting?
2. Per 2-EOP-LOCA-1, what procedure will the CRS direct NEXT?
A. (1) Charging and SI (2) 2-EOP-LOCA-2, Post LOCA Cooldown and Depressurization
B. (1) Charging ONLY (2) 2-EOP-TRIP-3, SI Termination
C. (1) Charging and SI (2) 2-EOP-TRIP-3, SI Termination
D. (1) Charging ONLY (2) 2-EOP-LOCA-2, Post LOCA Cooldown and Depressurization
▶ Show Answer & Explanation
✓ C. Correct. Basically the conditions in the stem describes a small break LOCA and the conditions will meet SI Termination criteria in EOP-LOCA-1 and the SRO will transition to EOP-TRIP-3 (SI Termination). In EOP-TRIP-3, the crew will reduce ECCS injection flow, which with the unisolable PZR vapor space leak (SBLOCA), RCS pressure will lower when ECCS injection flow is reduced. EOP-TRIP-3 will then transition the crew to EOP-LOCA-2. RCS pressure at 1450 psig, will be above the shutoff head for the SI and Charging Pumps and will both be injection flow into the RCS.
✗ A. First part is correct. Second part is incorrect. Plausible because you would ultimately end up on 2-EOP-LOCA-2. Incorrect in that it would not be the next procedure path to transition to.
✗ B. First part is incorrect. Plausible if the operator incorrectly recalls the shutoff head for an SI pump. Second part is correct.
✗ D. First part is incorrect. Second part is incorrect.
Ref: 2-EOP-LOCA-1 (R42), 2-EOP-LOCA-2 (R41), 2-EOP-TRIP-3 (R41) | LO: NOS05LOCA01-07, Objective 3 | Source: Modified Bank - Callaway 2021 NRC SRO76 | Cognitive: Comprehension/Analysis
Connections
- Related systems: Pressurizer & PRT, ECCS
- Related EOPs: EOP-LOCA-1 — Loss of Reactor or Secondary Coolant, EOP-LOCA-2 — Post LOCA Cooldown and Depressurization, EOP-TRIP-3 — SI Termination
- Related exam: 2023 NRC Written Exam