Q39 — CFCU Power Supplies / 4KV Vital Bus Loss
022 K2.01 (3.6)
Given:
• Salem Unit 2 experienced a reactor trip and safety injection actuation due to a LOCA
• 23 CFCU is CIT for maintenance
• 2B 4KV Vital Bus de-energized on Bus Differential protection
Which of the following identifies the status of the CFCUs?
• Salem Unit 2 experienced a reactor trip and safety injection actuation due to a LOCA
• 23 CFCU is CIT for maintenance
• 2B 4KV Vital Bus de-energized on Bus Differential protection
Which of the following identifies the status of the CFCUs?
A. 22 and 25
B. 22 and 24
C. 21 and 24
D. 21 and 25
▶ Show Answer & Explanation
✓ D. Correct. With 2B 4KV Vital Bus de-energized: 22 CFCU (B bus) and 24 CFCU (B bus) cannot run. With 23 CFCU CIT for maintenance: 23 cannot run. Only 21 CFCU (A bus) and 25 CFCU (C bus) remain available and running.
✗ A. Incorrect. 22 CFCU is powered from the B bus, which is de-energized. 22 cannot run. 25 (C bus) is correct.
✗ B. Incorrect. Both 22 and 24 CFCUs are powered from the B bus, which is de-energized. Neither can run.
✗ C. Incorrect. 24 CFCU is powered from the B bus, which is de-energized. 24 cannot run. 21 (A bus) is correct.
Ref: NOS05CONTMT-17 | Source: Bank - Salem | Cognitive: Fundamental/Memory
Connections
- Related systems: CFCUs, 500KV
- Related exam: 2023 NRC Written Exam