Q22 — EDG Failure / ECCS Load Status
064 ED/G-K3.02 (4.2)
Given:
At time 10:00:00
• A Reactor Trip and Safety Injection have occurred coincident with a LOOP at Unit 2
• EDG 2B can NOT be started
At 10:15:00, which ONE of the following completes the statement below?
22 RHR Pump is _(1)_ and 22 SI Pump is _(2)_.
At time 10:00:00
• A Reactor Trip and Safety Injection have occurred coincident with a LOOP at Unit 2
• EDG 2B can NOT be started
At 10:15:00, which ONE of the following completes the statement below?
22 RHR Pump is _(1)_ and 22 SI Pump is _(2)_.
A. _(1)_ stopped _(2)_ running
B. _(1)_ stopped _(2)_ stopped
C. _(1)_ running _(2)_ running
D. _(1)_ running _(2)_ stopped
▶ Show Answer & Explanation
✓ A. Correct. 22 RHR pump is powered from 2B 4KV Vital Bus and 22 SI Pump is powered from 2C 4KV Vital Bus. Additionally, 2B EDG can not be started after the LOOP occurs. Consequently, 15 minutes after a reactor trip and safeguards have occurred (coincident with the loop), 2A and 2C Vital Busses are being powered from EDG 2A and EDG 2C and all of the appropriate ECCS loads have been loaded onto the running EDGs. Therefore, at 10:15:00, 22 RHR Pump is stopped and 22 SI Pump is running.
✗ B. Incorrect but plausible. Part 1 is correct. For Part 2, the candidate could incorrectly conclude that 22 SI pump is powered from 2B 4KV Vital Bus. This would result in the candidate incorrectly deducing that at 10:15:00, the 22 SI Pump is stopped.
✗ C. Incorrect but plausible. For Part 1, the candidate could incorrectly conclude that 22 RHR pump is powered from 2C 4KV Vital Bus. This would result in the candidate incorrectly deducing that at 10:15:00, the 22 RHR Pump is running. Part 2 is correct.
✗ D. Incorrect but plausible. For Part 1, the candidate could incorrectly conclude that 22 RHR pump is powered from 2C 4KV Vital Bus. This would result in the candidate incorrectly deducing that at 10:15:00, the 22 RHR Pump is running. For Part 2, the candidate could incorrectly conclude that 22 SI pump is powered from 2B 4KV Vital Bus. This would result in the candidate incorrectly deducing that at 10:15:00, the 22 SI Pump is stopped.
Ref: NOS054KVAC0-08 (4160 ELECTRICAL SYSTEM) | LO: 9 — State the setpoints, coincidence, blocks and permissives for automatic actuations associated with the 4160 Electrical System | Source: New | Cognitive: Higher