Q92 — Containment Hydrogen Concentration
028G2.1.20 (4.6)
Given:
• The Unit 2 crew is performing 2-EOP-LOCA-1, Loss of Reactor Coolant, Step 24, "Containment Hydrogen Concentration."
• Containment Hydrogen Concentration is 2.1 %.
• The Unit 2 crew is performing 2-EOP-LOCA-1, Loss of Reactor Coolant, Step 24, "Containment Hydrogen Concentration."
• Containment Hydrogen Concentration is 2.1 %.
In accordance with 2-EOP-LOCA-1, which of the following describes the required procedural action(s)?
A. Start ONLY one Hydrogen Recombiner.
B. Start BOTH Hydrogen Recombiners.
C. Continue in 2-EOP-LOCA-1 until Containment Hydrogen concentration reaches 4.0%.
D. Consult TSC for additional recovery actions and continue in 2-EOP-LOCA-1.
▶ Show Answer & Explanation
✓ A. Correct. IAW 2-EOP-LOCA-1, if hydrogen concentration is between 0.5% and 4.0%, then only one hydrogen recombiner is started.
✗ B. Plausible because the operating procedure would start two recombiners if hydrogen concentration was 2.0% and rising. Candidate may also believe that the EOP starts both recombiners.
✗ C. Plausible because 4.0% is a decision parameter used in EOP-LOCA-1, step 24. Incorrect because concentration less than 4.0% results in the procedure directing the start of one recombiner.
✗ D. Plausible because consulting the TSC would have been the correct answer if hydrogen concentration was ≥ 4.0%.
Ref: 2-EOP-LOCA-1, Loss of Reactor Coolant and Bases. S2.OP-SO.CAN-0001(Q), Hydrogen Recombiner Operation. | LO: N/A | Source: Bank – ILOT 17-01 SRO NRC Exam – Q16 | Cognitive: Comprehension
Connections
- Related systems: Containment
- Related EOPs: EOP-LOCA-1 — Loss of Reactor or Secondary Coolant
- Related procedures: S2.OP-SO.CAN-0001 — Hydrogen Recombiner Operation
- Related exam: 2020 NRC Written Exam