RPCB (Reactor Power Cutback System) Flashcards
The unit is at 100% power. The reactor power cutback system is in service with subgroups 4, 5 and 22 selected for a loss of feedpump event. An operator at the Reactor Power Cutback System module (B04) pushes the TEST/RESET pushbutton twice. What actions will occur if the operator now simultaneously pushes the LOSS OF FEEDPUMP and DROP SUBGROUPS pushbuttons?
A. No actions will occur.
B. ONLY a turbine setback and turbine runback will occur.
C. ONLY a turbine runback will occur.
D. Subgroups 4, 5 and 22 will drop. A turbine setback and runback will occur and the load limiter will engage.
Answer: B
Which one of the following describes how a loss of NNN-D12 effects the operation of the RPCS?
A. The system will function to drop CEAs and runback the turbine and the setback feature will not function.
B. A turbine setback and runback will function, the CEAs will not drop.
C. The system will function to drop CEAs and all turbine features will not operate.
D. The system will function to drop CEAs, the runback feature will not function and the turbine will setback.
Answer: D
Consider the following pushbuttion on the Reactor Power Cutback Control Panel. “DROP SUBGRPS”
What will happen once this pushbutton is operated?
1. Pushing this button alone manually initiates a Reactor Power Cutback.
2. Pushing this button along with LARGE LOAD REJECT initiates a Reactor Power Cutback.
3. Pushing this button along with LOSS OF FEED PUMP initiates a Reactor Power Cutback.
4. Pushing this button deselects subgroups.
A. 4
B. 1
C. 2 and 3
D. 1, 2 and 3
Answer: C
After a Reactor Power Cutback, the CEAs dropped by the RPCS:
A. can be positioned by the RRS approximately 10 seconds after the initiation of the RPCB.
B. must be positioned manually in order to adjust Tavg.
C. can be positioned by the RRS immediately after the RPCB.
D. can not be moved in manual or automatic until the RPCS is taken out of service.
Answer: A
Unit 1 is operating at rated power. Subgroup 5 has been transferred to the hold bus. The ‘B’ Main Feed Pump trips. Which of the following describe the plant response?
A. A RPCB will initiate with group four providing sufficient negative reactivity to offset the reduction of feedwater.
B. A normal RPCB will be initiated.
C. The reactor will trip if group 5 is not inserted manually within 40 seconds following the RPCB signal.
D. The reactor will trip immediately.
Answer: D
Unit 1 is operating at rated power A Regulating Group 5 CEA has been determined to be UNTRIPPABLE (STUCK) The Operating Crew is reviewing the Tech Specs associated with this problem While they are performing this, a trip of the ‘B’ MFP occurs Based on this, which ONE of the following describes how the plant will respond?
A. The reactor will trip immediately.
B. A normal RPCB will be completed.
C. The reactor will trip in approximately 30 seconds.
D. A RPCB will occur, however a building penalty factor will eventually (within 10 minutes) lead to a plant trip.
Answer: A
Unit 1 is operating at rated power. CEA Sub Group 5 (Regulating Group 4) has been transferred to the hold bus. The ‘A’ Main Feed Pump trips. Based on these conditions, you should expect…
A. an immediate reactor trip.
B. a normal RPCB.
C. a reactor trip in approximately 30 seconds.
D. a RPCB, with half of Regulating Group 4 CEAs remaining at the top of the core.
Answer: A
The subgroup assigned to Regulating Group 5 has been transferred to the hold bus. The associated power switch has been removed from the cabinet for repair. A Reactor Power Cutback initiates due to a loss of a main feed pump and the RPCB system has commanded the Reg Gp 5 subgroup to drop. Reg Group 5 will initially…
A. remain in position.
B. drive in auto sequential.
C. drop as commanded by RPCS.
D. remain in position until the operator attempts to drive the Reg Gp 5 subgroup in, causing the subgroup to drop.
Answer: A
Unit 1 is operating at rated power. A loss of NNN-D12 occurs. Shortly after this, the ‘B’ MFP trips. Based on these conditions, with no operator action, the operating crew can expect…
A. A RPCB followed by a reactor trip due to secondary power (steam demand) being significantly higher than primary power.
B. Plant stabilization after a manual RPCB.
C. Plant stabilization after an automatic RPCB.
D. A RPCB followed by a reactor trip due to secondary power (steam demand) being significantly lower than primary power.
Answer: A
Which of the following conditions will cause a CWP?
A. Low SG pressure pre trip
B. ASI pre trip
C. VOPT pre trip
D. Reactor Power Cutback
Answer: D
Unit 1 is operating at rated power with the RPCS in service. The TEST/RESET pushbutton is inadvertently pressed and backlights. Realizing this mistake, the operator depresses this pushbutton again and the backlight goes out. Several minutes later, one of the Main Feed Pumps trips. Which one of the following describes the response of the RPCB?
A. A RPCB will not occur.
B. A turbine setback and runback will occur, but the CEAs will not drop.
C. A normal RPCB will occur.
D. CEAs will drop, but a turbine setback and runback will not occur.
Answer: B
Unit 1 is operating at rated power. RPCS is in service with subgroups 4, 5 and 22 selected. A Main Feed Pump trips. In an unrelated failure, a Steam Header Pressure Transmitter (PT- 1024) fails low. Based on this, the RPCS will drop selected CEAs and the Main Turbine will ____________.
A. Setback, Continuously Runback.
B. Setback, Not Runback.
C. Not Setback, Not Runback.
D. Not Setback, Continuously Runback.
Answer: A
Unit 1 is being shutdown and is presently at 75% power. The CRS has directed you to de-select the CEAs from the RPCB. The CRS desires that the RPCS remain in service (with CEAs de-selected). In order to complete this task, the operator must depress the AAOOS…
A. and then the TEST/RESET pushbuttons to backlight them, then depress the TEST/RESET and then the AAOOS pushbuttons once to remove the backlight.
B. pushbutton to backlight it.
C. and then the TEST/RESET pushbuttons to backlight them.
D. pushbutton to backlight it and then depress the same pushbutton to remove the backlight.
Answer: A
Which one of the following shows the correct unit(s) to express “Reactive Power”?
A. VARS
B. MVA
C. Joules
D. WATTS
Answer: A
Unit 1 is operating at rated power. The “A” feedwater pump trips. A single Group 5 CEA sticks out. Which ONE of the following best describes the plant response?
A. RPCB occurs followed by a CPC generated Reactor Trip in ~ 10 seconds.
B. Normal RPCB is completed.
C. RPCB occurs with the reactor regulating system driving in group 3 CEAs.
D. CPC generated Reactor Trip.
Answer: D
