Q77 — EOP-LOCA-1 H2 Recombiner and Hot Leg Recirc Timing
EPE: 011 Large Break LOCA-G2.1.2 (4.4)
Given:
At time 07:00
• A Reactor Trip and Safety Injection have occurred due to a LBLOCA
At time 07:20
• The crew has transitioned to 1-EOP-LOCA-1 (Loss Of Reactor Coolant)
In accordance with 1-EOP-LOCA-1 (Loss Of Reactor Coolant), which ONE of the following completes the statements below?
The crew will start _(1)_ Hydrogen Recombiner(s) when Containment Hydrogen Concentration is greater than 0.5%.
_(2)_ is the EARLIEST time that the crew is required to perform 1-EOP-LOCA-4 (Transfer To Hot Leg Recirculation).
At time 07:00
• A Reactor Trip and Safety Injection have occurred due to a LBLOCA
At time 07:20
• The crew has transitioned to 1-EOP-LOCA-1 (Loss Of Reactor Coolant)
In accordance with 1-EOP-LOCA-1 (Loss Of Reactor Coolant), which ONE of the following completes the statements below?
The crew will start _(1)_ Hydrogen Recombiner(s) when Containment Hydrogen Concentration is greater than 0.5%.
_(2)_ is the EARLIEST time that the crew is required to perform 1-EOP-LOCA-4 (Transfer To Hot Leg Recirculation).
A. _(1)_ ONLY one _(2)_ 19:00
B. _(1)_ ONLY one _(2)_ 21:00
C. _(1)_ BOTH _(2)_ 19:00
D. _(1)_ BOTH _(2)_ 21:00
▶ Show Answer & Explanation
✓ B. Correct. For Part 1 and IAW 1-EOP-LOCA-1, the crew will start ONLY one Hydrogen Recombiner when Containment Hydrogen Concentration is greater than 0.5%. For Part 2 and IAW 1-EOP-LOCA-1, the crew is required to perform 1-EOP-LOCA-4 14 hours after the SI Actuation. Since the SI Actuation occurred at 07:00, the crew is required to perform 1-EOP-LOCA-4 at 21:00.
✗ A. Part 1 is correct. For Part 2, EOP-LOCA-1 has a requirement to start preparations for Hot Leg Recirculation 12 hours after the SI Actuation. Consequently, the candidate could incorrectly conclude that the crew is required to perform 1-EOP-LOCA-4 at 19:00.
✗ C. For Part 1, there are two hydrogen recombiners. Consequently, the candidate could incorrectly conclude that both hydrogen recombiners will be started during the performance of EOP-LOCA-1. For Part 2, EOP-LOCA-1 has a requirement to start preparations for Hot Leg Recirculation 12 hours after the SI Actuation. Consequently, the candidate could incorrectly conclude that the crew is required to perform 1-EOP-LOCA-4 at 19:00.
✗ D. For Part 1, there are two hydrogen recombiners. Consequently, the candidate could incorrectly conclude that both hydrogen recombiners will be started during the performance of EOP-LOCA-1. Part 2 is correct.
Ref: 1-EOP-LOCA-1 | LO: NOS05LOCA01-05 (EOP-LOCA-01, LOSS OF REACTOR COOLANT) | Source: New | Cognitive: Higher
Connections
- Related systems: Containment, ECCS, RCS
- Related EOPs: EOP-LOCA-1 — Loss of Reactor or Secondary Coolant, EOP-LOCA-4 — Transfer to Hot Leg Recirculation
- Related procedures: S2.OP-SO.CAN-0001 — Hydrogen Recombiner Operation
- Related exam: 2018 NRC Written Exam