Q5 — ECCS/CCW SEC Mode III
006 ECCS-K1.11 (2.8)
Given:
- Unit 2 is at 100% Reactor Power
- 21 and 22 CCW Pumps are in service
At time 12:00
- A Reactor Trip and Safety Injection have occurred coincident with a LOOP
Which ONE of the following completes the statements below?
At 12:01, the SECs are operating in _(1)_.
After the SECs have completed their loading, 21 and 22 CCW Pumps will be _(2)_.
- Unit 2 is at 100% Reactor Power
- 21 and 22 CCW Pumps are in service
At time 12:00
- A Reactor Trip and Safety Injection have occurred coincident with a LOOP
Which ONE of the following completes the statements below?
At 12:01, the SECs are operating in _(1)_.
After the SECs have completed their loading, 21 and 22 CCW Pumps will be _(2)_.
A. (1) Mode II (2) running
B. (1) Mode II (2) stopped
C. (1) Mode III (2) running
D. (1) Mode III (2) stopped
▶ Show Answer & Explanation
✓ D. Correct. For Part 1, the SECs will be operating in Mode 3 (SI + Blackout) following a Reactor Trip and Safety Injection coincident with a LOOP. For Part 2, the CCW Pumps will not automatically start as part of SEC Mode 3 loading.
✗ A. Incorrect but plausible. For Part 1, the SECs have 4 modes of operation. SEC Mode 2 operation is only for a Station Blackout. Given there is a Station Blackout as part of the questions stem, the candidate could incorrectly conclude that the SECs are operating in Mode 3. For Part 2, CCW cools several ECCS components (RHR Pumps, RHR HX and SI Pumps). Consequently, the candidate could incorrectly conclude that with a SI and LOOP in progress, the SECs will automatically restart the CCW Pumps.
✗ B. Incorrect but plausible. For Part 1, the SECs have 4 modes of operation. SEC Mode 2 operation is only for a Station Blackout. Given there is a Station Blackout as part of the questions stem, the candidate could incorrectly conclude that the SECs are operating in Mode 3. Part 2 is correct.
✗ C. Incorrect but plausible. Part 1 is correct. For Part 2, CCW cools several ECCS components (RHR Pumps, RHR HX and SI Pumps). Consequently, the candidate could incorrectly conclude that with a SI and LOOP in progress, the SECs will automatically restart the CCW Pumps.
Ref: NOS05RHR000-16, NOS05CVCS00-17 | LO: NOS05ECCS00-09 | Source: New | Cognitive: Higher
Connections
- Related systems: SECs, ECCS, CCW
- Related exam: 2019 NRC Written Exam