Q79 (SRO) — LOOP / EDG Trip / TS 3.8.1.1 LCO 3.0.4.b
056 Loss of Offsite Power-AA2.22 (3.6)
Given:
• Unit 2 is in MODE 4 during a plant startup
At time 01:00
• A LOOP occurs
At time 02:00
• EDG 2A Engine Lube Oil Header Low Pressure local alarm and EDG 2A Engine Generator Tripped local alarm actuate
At time 02:10
• EDG 2A is declared inoperable
At time 04:00
• Offsite power has been restored
• ALL independent AC circuits between the offsite transmission network and the onsite Class 1E distribution system are OPERABLE
• Maintenance estimates that the 2A EDG will be repaired within the next 24 hours
Which ONE of the following completes the statement below?
At 02:00, 2A EDG tripped when Engine Lube Oil Header Low Pressure FIRST lowered below _(1)_ psig.
In accordance with Technical Specifications, Unit 2 _(2)_.
• Unit 2 is in MODE 4 during a plant startup
At time 01:00
• A LOOP occurs
At time 02:00
• EDG 2A Engine Lube Oil Header Low Pressure local alarm and EDG 2A Engine Generator Tripped local alarm actuate
At time 02:10
• EDG 2A is declared inoperable
At time 04:00
• Offsite power has been restored
• ALL independent AC circuits between the offsite transmission network and the onsite Class 1E distribution system are OPERABLE
• Maintenance estimates that the 2A EDG will be repaired within the next 24 hours
Which ONE of the following completes the statement below?
At 02:00, 2A EDG tripped when Engine Lube Oil Header Low Pressure FIRST lowered below _(1)_ psig.
In accordance with Technical Specifications, Unit 2 _(2)_.
A. (1) 40 (2) can go to MODE 3 ONLY if a risk assessment is performed
B. (1) 40 (2) can NOT go to MODE 3 until 2A EDG is restored to OPERABLE status
C. (1) 60 (2) can go to MODE 3 ONLY if a risk assessment is performed
D. (1) 60 (2) can NOT go to MODE 3 until 2A EDG is restored to OPERABLE status
▶ Show Answer & Explanation
✓ B. Correct. For Part 1 and IAW S2.OP-AR.DG-0001, 2A EDG tripped when Engine Lube Oil Header Low Pressure FIRST lowered below 40 psig. For Part 2: At 01:00, the crew is in LCO 3.8.1.1 REQUIRED ACTION d. However, at 04:00, LCO 3.8.1.1 REQUIRED ACTION d is no longer applicable and LCO 3.8.1.1 REQUIRED ACTION b and h are now applicable. LCO 3.8.1.1 REQUIRED ACTION h states LCO 3.0.4.b is not applicable to DGs. Since LCO 3.0.4.b is not applicable to the DGs, Unit 2 can NOT go to MODE 3 until 2A EDG is restored to OPERABLE status.
✗ A. Part 1 is correct. For Part 2, the candidate could incorrectly interpret LCO 3.8.1.1 to allow a MODE change if a risk assessment is performed.
✗ C. For Part 1, the EDG ENGINE LUBE OIL HEADER LOW PRESSURE ALARM actuates when pressure lowers to 60 psig. Consequently, the candidate could incorrectly conclude the EDG will trip when Engine Lube Oil Header Low Pressure FIRST lowered below 60 psig. For Part 2, the candidate could incorrectly interpret LCO 3.8.1.1 to allow a MODE change if a risk assessment is performed.
✗ D. For Part 1, the EDG ENGINE LUBE OIL HEADER LOW PRESSURE ALARM actuates when pressure lowers to 60 psig. Consequently, the candidate could incorrectly conclude the EDG will trip when Engine Lube Oil Header Low Pressure FIRST lowered below 60 psig. Part 2 is correct.
Ref: S2.OP-AR.DG-0001, LCO 3.8.1.1, LCO 3.0.4.b | LO: NOS05TECHSPEC-12 | Source: New | Cognitive: Higher
Connections
- Related systems: EDGs
- Related procedures: S2.OP-AR.DG-0001 — EDG Alarm Response
- Related tech specs: TS 3/4.8 — Electrical, TS 3/4.0 — Applicability
- Related exam: 2019 NRC Written Exam