Q60 — ADFCS SG Level Channel Failure
035000K6.03 (2.6)
Given:
• Unit 2 is at 100% Power.
• Steam Generator level control and SGFPs are in AUTO.
• 21 Steam Generator NR Level Channel I failed high due to a sensor malfunction.
• No corrective actions have been initiated yet.
Complete the following statement concerning the response of the feedwater control system if 21 Steam Generator NR Level Channel II fails LOW?
The Ovation Advanced Digital Feedwater System will initiate OHA G-7, ADFCS ALTERNATE ACTION, and ....
• Unit 2 is at 100% Power.
• Steam Generator level control and SGFPs are in AUTO.
• 21 Steam Generator NR Level Channel I failed high due to a sensor malfunction.
• No corrective actions have been initiated yet.
Complete the following statement concerning the response of the feedwater control system if 21 Steam Generator NR Level Channel II fails LOW?
The Ovation Advanced Digital Feedwater System will initiate OHA G-7, ADFCS ALTERNATE ACTION, and ....
A. ONLY 21BF19 will shift to MANUAL
B. BOTH 21BF19 and 21BF40 will shift to MANUAL
C. ALL BF19's and BF40's remain in AUTOMATIC
D. 21BF19, 21BF40, and BOTH SGFPs shift to MANUAL
▶ Show Answer & Explanation
✓ B. Correct. Two inputs in Quality Alarm (BAD) will result in ADFCS Alternate Action (OHA G-7) and the transfer of both BF19 & BF40 controllers to MANUAL.
✗ A. Incorrect. Plausible because at high power level only the BF19 is being controlled.
✗ C. Incorrect. Plausible because the candidate may believe that digital feed circuitry will use the remaining good channel III and the controllers will remain in AUTO.
✗ D. Incorrect. Plausible because the previous digital feed system design would have resulted in this configuration.
Ref: NOS05ODFWCS-02, Ovation Advanced Digital Feedwater Control System | LO: ELO 12 | Source: Bank, Salem Vision Database | Cognitive: Comprehension
Connections
- Related systems: Feed & Condensate, Steam Generator & Blowdown
- Related exam: 2020 NRC Written Exam