Q58 — Hydrogen Recombiner System / EOP-LOCA-1
T2G2 028 K3.02 (2.9)
Which of the following completes both statements concerning operation of the Hydrogen Recombiner System during a Design Bases Accident (assume hydrogen concentration is within the range that allows operation of the hydrogen recombiner system)?
1. The maximum number of hydrogen recombiners that can be placed in service is (1).
2. What is the concern if hydrogen recombiner system cannot be placed in service when required?
1. The maximum number of hydrogen recombiners that can be placed in service is (1).
2. What is the concern if hydrogen recombiner system cannot be placed in service when required?
A. (1) 1 (2) Gas vapor binding of ECCS pumps resulting in loss of core cooling.
B. (1) 1 (2) Explosive atmosphere resulting in containment failure.
C. (1) 2 (2) Explosive atmosphere resulting in containment failure.
D. (1) 2 (2) Gas vapor binding of ECCS pumps resulting in loss of core cooling.
▶ Show Answer & Explanation
✓ B. Correct. Per 2-EOP-LOCA-1 step 17, only one Hydrogen Recombiner is allowed to be placed in service when the Hydrogen concentration is between > 0.5% and < 4%. The bases for running a Hydrogen Recombiner is to reduce the hydrogen concentration to prevent the formation of a flammable mixture that could ignite and cause an explosion and pressure excursion that could challenge containment integrity.
✗ A. Plausible because gas intrusion into the ECCS system can adversely affect the operation of ECCS pumps.
✗ C. Plausible because the operator may believe that both hydrogen combiners can be operated to maximize the reduction of hydrogen when hydrogen concentration is at the upper end (4%). Incorrect in that operation of both hydrogen recombiners is not permitted.
✗ D. Plausible because gas intrusion into the ECCS system can adversely affect the operation of ECCS pumps. Plausible because the operator may believe that both hydrogen combiners can be operated to maximize the reduction of hydrogen when hydrogen concentration is at the upper end (4%). Incorrect in that operation of both hydrogen recombiners is not permitted.
Ref: 2-EOP-LOCA-1 (R41) | LO: NOS0SLOCA01-07, Objective 6.j — Describe the plant response to actions taken in the following EOP step sequence(s): Containment Hydrogen Concentration | Source: Bank — Salem | Cognitive: Comprehension/Analysis
Connections
- Related systems: Containment
- Related procedures: EOP-LOCA-1 — Loss of Reactor or Secondary Coolant
- Related exam: 2023 NRC Written Exam