RRS (Reactor Regulating System) Flashcards
The plant is operating at 50% power. RRS Tavg is selected to AVERAGE. Tcold loop 1 fails low. Which of the following describes RRS response to this failure?
A. AMI is generated, PLCS auto setpoint increases, Tavg - Tref meter shows a temperature deviation.
B. AMI is generated, PLCS auto setpoint decreases, Tavg - Tref meter shows a temperature deviation.
C. AWP is generated, PLCS auto setpoint decreases, Tavg - Tref meter shows a temperature deviation.
D. AWP is generated, PLCS auto setpoint increases, Tavg - Tref meter shows NO temperature deviation.
Answer: B
Which one of the following describes how RRS develops CEA motion demand?
A. Power error compensated by rate of change of temperature error signal.
B. Power error signal ONLY.
C. Temperature error ONLY.
D. Temperature error compensated by rate of change of power error signal.
Answer: D
Which one of the following RRS failures would result in an AMI (Automatic Motion Inhibit) and an AWP (Automatic Withdrawal Prohibit)? Assume all switches are in AVERAGE.
A. UIC #1 fails low
B. Tcold fails low
C. TLI fails high
D. Tcold fails high
Answer: D
Unit 1 is operating at 100% power. RRS Tave is selected to LOOP #2. TAVG - TREF HI-LO alarms. LOOPS TEMP Hi alarms. All Control Systems in their normal Full Power Line-up. Which of the following would be an immediate consequence of the above indications, if the alarms were caused by an instrument malfunction?
A. Letdown increasing dramatically.
B. Pressurizer spray full on.
C. CEAs driving in.
D. SBCS permissive signal in for all valves.
Answer: C
Unit 1 is operating at 5% power during a plant startup. The Pressurizer Level master Controller is in REMOTE and AUTO. The Pressurizer Level Control selector switch is in “X”. RRS is aligned to monitor average Tave. A Tc instrument (RCN-TT-111Y) fails HIGH. Which one of the following describes the expected plant response?
A. The standby charging pump starts.
B. This failure will have no impact.
C. Letdown flow will begin to decrease.
D. The normally running charging pump stops.
Answer: C
With the plant operating at 100% power steady state conditions, which of the following describes plant response to a T-hot input failing high when RRS is selected to that channel? (Assume all controls are in automatic and NO operator action) RRS will send….
A. an AWP signal to CEDMCS due to Tref > Tave.
B. an AMI signal to CEDMCS.
C. a signal to CEDMCS causing CEA’s to insert.
D. a signal to CEDMCS causing CEA’s to withdraw.
Answer: C
Reactor power is at 50%, the following plant conditions exist:
Tc (RCN-TI-111Y) indicates 564°F.
Tc (RCN-TI-121Y) indicates 650°F.
Th (RCN-TI-111X and 121X) indicate 592°F.
RRS is selected to Tavg 2.
Board Annunciators in alarm:
Tavg/Tref Hi-Lo
RC Loop Temp Hi
CEA high rate insertion demand indicator is lit. CEA auto insertion occurring. Turbine load matches Reactor power. If there is no operator actions taken, which of the following describes this event?
A. SBCS will receive a runback inhibit.
B. Pressurizer pressure will increase.
C. Pressurizer pressure will lower.
D. SBCS will receive a quick open block.
Answer: C
100% power. RRS in Auto and selected to AVERAGE Tave Loop 2 Tc fails HI Which one of the following is correct?
A. Turbine runback initiated to bring Tavg - Tref within +2°F.
B. AMI generated by LOOP 1 Tc indicated > 575°F.
C. CEA high withdrawal occurring to mismatch between temperature error and power error.
D. AMI generated by Tavg deviation.
Answer: D
Reactor power 50% and stable CEDMCS in AS RRS selected to Tave 1. T-hot instrument RCN-TI-111X fails low CEA’s are withdrawing Crew selects Tave 2 at RRS Test Panel If no other actions are taken by the crew, the CEA’s will:
A. insert to match Tavg with Tref.
B. continue to withdraw until stopped by an AWP.
C. withddraw to match Tavg with Tref.
D. stop moving due to the generated AMI.
Answer: A
Unit 1 is operating at rated power when backpressure in the Main Condenser starts to rise. Regulating Group 5 is at 135 inches. Turbine load is being shifted to SBCS valve 1007 in an effort to stabilize backpressure. CEDMCS is inadvertently left in AUTO SEQUENTIAL. Assuming Steam Demand remains constant. The Operating Crew should expect CEAs to…
A. start stepping in.
B. start stepping out.
C. remain in their present position due to AMI.
D. remain in their present position due to AWP.
Answer: A
Unit is operating at 100% power. Regulating Group 5 is at 135”. RRS selected to Control Channel #1. Control Channel #1 fails high. CEDMCS in Auto Sequential Which one of the following is correct? CEAs……
A. may withdraw a few steps.
B. may insert a few steps.
C. will not move due to an AMI.
D. will insert until CEDMCS is taken out of automatic.
Answer: B
The plant is at 100% power when suddenly the following alarms and indications are observed in the Control Room: Reactor power decrease. Tavg/Tref Hi-Lo Alarm Window 4A08B on B04 with RCS temperatures decreasing. One four-fingered CEA bottom light on the core mimic and LEL lit. Pressurizer level and pressure decrease. COLSS, CPC, & PDIL alarms. Expected CVCS actions due to decreasing pressurizer level. Which ONE of the following conditions would MOST likely be observed in the next five minutes, if NO operator actions were taken?
A. The reactor would have tripped due to low pressurizer pressure.
B. Reactor power would stabilize at ~ 100% with a higher than full power Tavg.
C. Reactor power would stabilize at 50% with a lower than full power Tavg.
D. Reactor power would stabilize at ~ 100% power with a lower than full power Tavg.
Answer: D
Group 5 CEAs are 140 inches withdrawn with CEDMCS in Auto sequential. A Control Channel detector fails high. RRS is selected to the failed detector. Which of the following describes the RRS response.
A. No CEA motion will occur due to an AMI being generated.
B. CEAs may insert a few steps due to the Rate of Change circuit sensing a power error.
C. No CEA motion will occur due to the Rate of Change circuit eliminating the effects of the instrument failure.
D. CEAs may attempt to withdraw a few steps due to the Rate of Change circuit sensing a power error.
With RRS Tavg selected to AVERAGE, which of the following will generate a Reactor Regulating System Automatic Motion Inhibit (AMI):
Answer: B
The plant is operating at 100% power. A single NI control channel has failed to 0%. With no operator actions, which of the following is true concerning the DFWCS?
A. There will be no effect on the plant.
B. S/G levels will rapidly increase.
C. The unit will go through feedwater swapover.
D. Both downcomers control valves will go closed.
Answer: A
With RRS Tavg selected to AVERAGE, which of the following will generate a Reactor Regulating System Automatic Motion Inhibit (AMI):
A. Th > 575°F.
B. Tavg deviation > 5°F.
C. Tc > 575°F.
D. Tavg - Tref > 6°F.
Answer: B
