Q27 — CFCU SEC Mode 1 Response
103 Containment-K1.01 (3.6)
Given:
• Unit 2 is at 100% Reactor Power and stable
• 21-24 CFCUs are running in high speed
• 25 CFCU is stopped
At time 13:50
• A Reactor Trip and Safety Injection have occurred
Ten minutes later at 14:00, which ONE of the following completes the statement below?
21-24 CFCUs are running in _(1)_ speed and 25 CFCU is _(2)_.
• Unit 2 is at 100% Reactor Power and stable
• 21-24 CFCUs are running in high speed
• 25 CFCU is stopped
At time 13:50
• A Reactor Trip and Safety Injection have occurred
Ten minutes later at 14:00, which ONE of the following completes the statement below?
21-24 CFCUs are running in _(1)_ speed and 25 CFCU is _(2)_.
A. _(1)_ high _(2)_ stopped
B. _(1)_ high _(2)_ running in high speed
C. _(1)_ low _(2)_ stopped
D. _(1)_ low _(2)_ running in low speed
▶ Show Answer & Explanation
✓ D. Correct. At 14:00:00 the SECs will be in MODE 1. This will cause the running CFCUs to stop and then all of the CFCUs will be started in low speed. Consequently, at 14:00:00, 21-24 CFCUs are running in low speed and 25 CFCU is running in low speed.
✗ A. Incorrect but plausible. The candidate could incorrectly conclude that with the SECs in Mode 1, this will cause only the previously running CFCUs to shift to high speed.
✗ B. Incorrect but plausible. The candidate could incorrectly conclude that with the SECs in Mode 1, this will cause all of the CFCUs to shift to high speed.
✗ C. Incorrect but plausible. The candidate could incorrectly conclude that with the SECs in Mode 1, this will cause only the previously running CFCUs to shift to low speed.
Ref: NOS05ESF000-02 (INTRODUCTION TO ENGINEERED SAFETY FEATURES AND DESIGN CRITERIA) | LO: 4 — Describe the function and operating characteristics for the Engineered Safety Features Standby Power System components: The Safeguards Equipment Cabinets | Source: Bank | Cognitive: Higher
Connections
- Related systems: CFCUs, SECs, ESF & Design
- Related exam: 2018 NRC Written Exam