RCS (Reactor Coolant System) Flashcards
Unit 1 is operating at rated power. Seal Injection is isolated to the RCPs due to a leak in the Aux building. Which of the following describes the effect (if any) that this has on the RCP temperatures.
A. HP Seal Cooler inlet temperature will rise to between 200°F and 220°F, all other seal temperatures should increase by about 70°F.
B. Isolating Seal Injection should have NO impact on the seal temperatures.
C. HP Seal Cooler inlet temperature will rise to between 200°F and 220°F while all other seal temperatures remain normal.
D. HP Seal Cooler inlet temperature should remain relatively constant, while all other seal temperatures should increase by about 70°F.
Answer: C
The plant is operating at full power with the following reactor coolant pump (RCP) 1B indications:
Seal injection flow is 7.1 gpm
NC flow is 520 gpm
#2 seal inlet pressure is 1850 psig #2 seal outlet pressure is 450 psig Which one of the following conditions is indicated on RCP 1B? A. #1 seal degradation. B. HP seal cooler leak. C. #2 seal degradation. D. #1 and #2 seal degradation.
Answer: A
Unit 1 is operating at rated power. The following parameters are indicated for the 1B RCP:
Seal #1 inlet pressure…………2250 psia
Seal #2 inlet pressure…………2225 psia
Seal #2 outlet pressure……….440 psia
Controlled bleedoff flow………5.9 gpm
Seal #1 inlet temperature…….110°F
Seal #2 inlet temperature…….105°F
Seal #2 outlet temperature…..105°F
WHICH ONE of the following describes the required action(s) for these conditions?
A. Trip reactor, stop RCN-P01B and isolate controlled bleedoff.
B. Commence plant shutdown by 40OP-9ZZ05, Power Operations.
C. Trip reactor, stop all reactor coolant pumps and isolate controlled bleedoff.
D. Initiate a RPCB to rapidly reduce power, then continue the shutdown using 40OP-9ZZ05, Power Operations.
Answer: B
Which one of the following components is tripped to minimize heat input into the RCS after a Loss of All Feedwater?
A. Reactor Coolant Pumps.
B. Pressurizer heaters.
C. Charging pumps.
D. Heated junction thermocouples.
Answer: A
Leakage past Reactor Coolant Pump Vapor Seal goes to the…
A. Volume Control Tank.
B. CVCS Holdup Tank.
C. Reactor Drain Tank.
D. Equipment Drain Tank.
Answer: C
The reactor has been manually tripped. Pressurizer pressure is 1810 psia and slowly lowering. SPTA’s have been completed. All ESFAS systems are performing as designed. RCS subcooling is 20°F and slowly lowering. Containment temperature is 145°F. 4 RCP’s are running. The crew is required to…..
A. trip one RCP in each loop.
B. trip RCP’s 1A and 1B.
C. trip all four RCP’s.
D. trip all four RCP’s when subcooling is less than 0°F
Answer: C
The reactor has been manually tripped A small LOCA has occurred. The LOCA procedure has been implemented. Under what conditions would an operator be required to trip 2 RCP’s and under what conditions would an operator be required to trip all RCP’s?
A. actuation of CSAS and trip all RCPs on subcooled margin of less than 24 degrees.
B. actuation of MSIS and trip all RCPs on a loss of subcooling.
C. pressurizer pressure remaining below 1837 psia and trip all RCPs on subcooled margin of less than 24 degrees.
D. pressurizer pressure remaining below 1837 psia and trip all RCPs on a loss of seal injection flow.
Answer: C
The unit is at 100% power. It has been determined that a 150 gpm high pressure seal cooler leak exists. Before the affected HPSC is isolated, which one of the following describes the limitations on plant operation?
A. Nuclear cooling water flow to the affected RCP must be increased.
B. The plant must commence a normal shutdown within 72 hours.
C. The affected RCP must be stopped, resulting in a automatic trip.
D. The plant must be manually tripped and all RCP’s must be stopped.
Answer: D
A hot leg break has occurred. All reactor coolant pumps are stopped. Representative core exit thermocouple temperature is 450°F. Maximum quadrant core exit thermocouple is 456°F. T-hot is 483°F and dropping. Pressurizer pressure is 610 psia. Containment temperature and pressure are 125°F and 2.0 psig. WHICH ONE of the following identify the condition of heat transfer in the reactor coolant system?
A. Saturated natural circulation (reflux boiling)
B. Saturated steaming through the break
C. Subcooled natural circulation
D. Subcooled natural circulation with localized flow blockage.
Answer: C
A LOCA occurred with the plant at 100% MOC. RCS pressure is currently 1860 psia. PZR level is 30% and stable. The leak rate was 135 gpm into containment when RCS pressure was 2250 psia. Subcooled margin is 48°F and stable. The reactor was manually tripped and SIAS/CIAS were manually initiated. No equipment is out of service Which one of the following describes the primary heat removal method that will be used during the cooldown? (assume the physical size of the RCS breach remains constant and CSAS does not actuate)
A. Reflux boiling
B. Forced circulation
C. HPSI injection
D. Subcooled natural circulation
Answer: B
A subcooled natural circulation cooldown is in progress following a small break LOCA in containment. Aux Spray is in use, lowering RCS pressure. Sub-Cooled Margin is 50°F and degrading slowly. Containment temperature is 120°. Pressurizer level is 45% and rising rapidly. HPSI is throttled. Reactor vessel head is reading 41%. The Control Room Staff should immediately…
A. open the reactor vessel head vents.
B. re-initiate full Safety Injection flow.
C. stop depressurizing the RCS.
D. exit LOCA and enter the functional recovery procedure.
Answer: C
An ESD has occurred inside containment. CSAS has failed to actuate. The Secondary Operator, attempting to actuate CSAS manually, ONLY rotates the switches for the A and C Channels on B05. Which one of the following should be expected?
A. Either the Train A containment spray valve OR the CS pump will actuate, but NOT both.
B. A Train CSAS will actuate.
C. Both CSAS Trains will actuate.
D. No CSAS actuation will occur.
Answer: D
Which of the following is NOT a reason that natural circulation of the RCS will be greater when the replacement SGs are installed.
A. During natural circulation, a lower delta-T will be developed across the core.
B. The increased decay heat load associated with the uprate to 3990 MWth.
C. There are more tubes in the replacement SGs, providing more flow.
D. Replacement SGs tubes are taller (higher), improving the driving thermal head.
Answer: A
Which one of the following is correct concerning the Reactor Coolant Pumps?
A. The Reactor Coolant Pumps are auto started on low pressure.
B. The Reactor Coolant Pumps discharge into the Steam Generators.
C. They add heat to the primary system during plant heatup.
D. The Reactor Coolant Pumps can be manually isolated from the Loops.
Answer: C
Which one of the following is a reason for the Reactor Coolant Pump (RCP) motor flywheel?
A. It increases the pump coastdown time and helps remove the initial decay heat from the Reactor Coolant System (RCS) when electrical power is lost to the motor.
B. It provides a counter balance to the effects of a large pump impeller.
C. It provides the necessary inerita to prevent a pump trip on a loss of normal off site power.
D. It provides a downward force to the pump shaft to counter act the upward force from the impeller.
Answer: A
The purpose of the RCP shaft seal assembly is to:
A. act as a pressure boundary between the RCS and containment.
B. prevent lubricating oil from mixing with the RCS.
C. filter the seal return flow before it goes to the VCT.
D. prevent any RCS liquid from flowing out of containment.
Answer: A
The Reactor Operator has been directed to stop RCP 1A, with the Oil Lift Pump for RCP 1A out-of-service. Which ONE of the following BEST describes this condition?
A. Impeller damage will occur to RCP 1A due to stopping torques.
B. RCP 1A will not stop without defeating interlock contacts.
C. RCP 1A’s thrust bearing will experience increased wear.
D. RCP 1A’s seal package will fail causing increased seal bleedoff.
Answer: C
The reactor is tripped. A small break LOCA is in progress. A loss of all Feedwater is in progress. Pressurizer level is 35%. Pressurizer pressure is 2275 psia and rising. Which one of the following would be an indication that RCS voiding is occurring?
A. RCS pressure increase when pressurizer spray is initiated.
B. Pressurizer level decrease when letdown flow is raised.
C. Pressurizer level increase when pressurizer spray is activated.
D. RCS pressure decrease when pressurizer heaters are energized.
Answer: C
The plant is operating at near 100% power level when seal injection flow to 2A Reactor Coolant Pump (RCP) is lost. Procedures allow continued pump operation as long as Nuclear Cooling Water flow is maintained. What is (are) the consequences of continued pump operation?
A. May shorten seal life if Nuclear Cooling water is not maintained above 95° F.
B. No effect on seal life due to seal design characteristics.
C. May shorten seal life due to the intrusion of contaminants into the seal system.
D. No effect on seal life since the Auxiliary impeller will supply adequate seal injection flow.
Answer: C
Unit 1 is in hot shutdown. RCP 1A is in hot standby. Seal injection has been lost 1A RCP #2 seal outlet temperature is 260°F Concerning the 1A RCP, the operator should close the seal bleedoff valve…
A. within 3 minutes.
B. immediately.
C. within 10 minutes.
D. within 15 minutes.
Answer: B
Unit 2 is in Mode 3 RCP 2A is in standby The Controlled Bleedoff Valve is open Which of the following conditions does not require the Controlled Bleedoff Valve to be closed?
A. Controlled bleedoff flow is 9.5 gpm
B. High Pressure Seal Cooler Leak
C. Two RCP 2A Seals indicate failed
D. Loss of Nuclear Cooling Water and it cannot be restored
Answer: C
Unit 1 is in Mode 3 RCP 1A is in standby The Controlled Bleedoff flow is 9 gpm Seal Injection is lost and cannot be restored What actions should the control room take?
A. Secure Nuclear Cooling Water to RCP 1A.
B. Isolate the High Pressure Seal Cooler.
C. Isolate seal bleedoff.
D. Close CHE- FV-241, Seal Injection to RCP 1A.
Answer: C
Unit 1 is operating at rated power. A failure of CHB-UV-515, letdown to regen heat exchanger, caused a loss of letdown. PZR level is 55%. The operating crew has stopped all charging pumps to establish conditions to support extended operations with letdown isolated. A loss of nuclear cooling water occurs. To avoid tripping the reactor and securing all RCPs, the operating crew must restore:
A. both seal injection and NC within 10 minutes.
B. seal injection within 10 minutes.
C. both seal injection and NC within 3 minutes.
D. NC within 3 minutes.
Answer: D
Unit 1 is at 100% power. An RCS leak to the NC system is in progress. Which of the following would be indicative of an RCS leak into the letdown heat exchanger?
A. backpressure control valve closing.
B. backpressure control valve opening.
C. indicated letdown flow increasing.
D. NC flow from the heat exchanger decreases.
Answer: A
