DFWCS Flashcards
The plant is at 100% power. All control input transmitters to the Digital Feedwater Control system are in service. A loss of NNN-D11 occurs. Which of the following describes the operator action(s), if any, that need to be taken to stabilize the plant?
A. Take manual speed control of MFP A and B
B. No operator action required
C. Take manual control of DFWCS A
D. Take manual control of DFWCS A and B
Answer: B
Unit 1 is at 100% power All control input transmitters to the Digital Feedwater Control system (DFWCS) are in service. A steam generator steam flow transmitter fails low. Which one of the following describes the automatic action that would take place in the DFWCS at a 50% deviation between the steam flow transmitter input signals? The affected master controller would:
A. shift to manual with the output signal that was present at the 8% deviation point.
B. remain in automatic but in single element control.
C. remain in automatic, 3-element control, using the good steam flow transmitter signal only.
D. remain in automatic 3-element control, using the sum of the two steam flow transmitters.
Answer: B
Reactor power is at 25% and DFWCS is in automatic. A feedwater temperature transmitter fails low. Which of the following represents the canned value that will be used by DFWCS?
A. 350 deg F
B. 0 deg F
C. 425 deg F
D. 500 deg F
Answer: C
Unit 1 is at 100% power All control input transmitters to the Digital Feedwater Control system (DFWCS) are in service and selected to AVERAGE(where applicable). One feedwater flow transmitter fails low. Which one of the following describes the operator action for this DFWCS input failure?
A. No action required because the DFWCS will automatically choose the higher flow at 4% flow deviation.
B. Place the lower reading feedwater flow transmitter into maintenance.
C. No action required because the DFWCS will automatically choose the higher flow at 8% flow deviation.
D. Place the higher reading feedwater flow transmitter to maintenance.
Answer: B
Which of the following inputs to the Digital Feedwater Control System is used for indication only?
A. Tavg
B. Downcomer flow transmitters
C. Turbine Load Index
D. Steam Bypass Master Controller output
Answer: B
