SI (Safety Injection)

Question 1

The HPSI cold leg injection orifice is used during simultaneous hot and cold leg injection to:

A. help balance SI flow to the hot and cold leg injection headers by being sized to allow approximately 50% flow.
B. provide instrumentation to measure flow to the hot and cold leg injection headers.
C. provide minimum recirculation flow for the HPSI pumps to prevent overheating.
D. prevent exceeding runout condition in the HPSI pumps to prevent pump cavitation.

Answer 1

Answer: A

Question 2

Which one of the following is true concerning the 1A safety injection tank? The safety injection tank can inject water into:

A. Loop 1A only.
B. Loop’s 1A and 2A.
C. Loop’s 1A and 1B.
D. Loop’s 1A, 1B, 2A and 2B.

Answer 2

Answer: A

Question 3

Which one of the following describes why the safety injection tanks are considered a passive system? (Assume the plant is at 100% power.)

A. Outlet valves automatically open on an actuation signal.
B. Tanks require minimal maintenance.
C. Injection from the tanks involves single manual action.
D. They require no electrical power to perform their function.

Answer 3

Answer: D

Question 4

Which of the following parameter values would exceed the allowable ECCS design criteria per 10CFR50.46 ?

A. 2% sump water Iodine 131 concentration.
B. 2150°F peak clad temperature.
C. 20% through wall clad degradation due to oxidation.
D. .75% hydrogen generation due to the zirc water reaction.

Answer 4

Answer: C

Question 5

Which one of the following will automatically occur when a recirculation actuation signal (RAS) is received?

A. Containment spray header isolation valve will open.
B. Refueling water tank outlet valve will close.
C. Low Pressure Safety Injection pumps will stop.
D. High Pressure Safety Injection pump discharge valve will close.

Answer 5

Answer: C

Question 6

Which of the following statements correctly identifies when a HPSI pump is to be used for Emergency Boration per 40AO-9ZZ01, “Emergency Boration”?

A. Anytime RCS pressure is less than HPSI shutoff head.
B. Anytime a SIAS/CIAS occurs.
C. Only if Charging pumps are unavailable.
D. Only if Reactor Coolant System Tcold is less than 350 degrees F.

Answer 6

Answer: C

Question 7

Which one of the following describes the signal that would have been generated when the reactor coolant system pressure lowers to 1800 psia?

A. Safety injection actuation signal
B. Main steam isolation signal
C. Recirculation actuation signal
D. Containment spray actuation signal

Answer 7

Answer: A

Question 8

Which one of the following describes the signal that will be generated when the pressurizer reaches 1837 psia?

A. Main Steam Isolation Signal (MSIS)
B. Safety Injection Actuation Signal (SIAS)
C. Recirculation Actuation Signal (RAS)
D. Containment Spray Actuation Signal (CSAS)

Answer 8

Answer: B

Question 9

Which of the following describes why the safety injection tanks do not dump their contents into the reactor coolant system during normal operation?

A. RCS pressure is less than SIT pressure and the force (D/P) upon the RCS check valves keep them closed.
B. The safety injection tanks are normally isolated until a SIAS signal is generated.
C. The safety injection tank injection valves are normally closed with their power supply breakers open.
D. RCS pressure is greater than SIT pressure and the force (D/P) upon the SIT check valves keep them closed.

Answer 9

Answer: D

Question 10

Which one of the following is an important reason to locate and stop a leak in the safety injection piping outside of containment during a large LOCA?

A. Reduces the amount of fixed contamination that will remain in the containment after repair of the leak.
B. Prevent safety injection pump runout during the injection phase following a LOCA.
C. A LOCA outside of containment could result in inadequate containment sump inventory to allow recirculation.
D. Prevent short circuit of the auxiliary building electrical systems with resultant possibility of electric shock.

Answer 10

Answer: C

Question 11

When filling a safety injection tank (NOP/NOT), which of the following is one possible consequence of stopping the HPSI pump and not closing the SIT fill/drain valve?

A. The SIT will flow into the RCS.
B. The SIT will flow into the RWT.
C. The RWT will flow into the SIT.
D. The RCS will flow into the SIT.

Answer 11

Answer: B

Question 12

Shutdown cooling is used to cool the Reactor Coolant System from a maximum of _____ to the temperature required for refueling.

A. 350°F
B. 250°F.
C. 410°F
D. 500°F

Answer 12

Answer: A

Question 13

A large break LOCA has occurred on Unit 2. Containment pressure is presently 13 psig. RWT level has dropped to approximately 6%. Which one of the following would you expect to occur based on this?

A. Safety injection suction valves from the RWT close.
B. Both HPSI pumps trip.
C. Containment spray valves close.
D. All safety injection pump recirculation valves close.

Answer 13

Answer: D

Question 14

Which one of the following is a reason for Containment Spray flow following a LOCA?

A. To prevent the containment sump pH from exceeding 7.0.
B. To minimize the containment sump oxygen levels.
C. To reduce containment pressure during a loss of coolant accident (LOCA).
D. To minimize the possibility of corrosion cracking of metallic components inside containment.

Answer 14

Answer: C

Question 15

Pressurizer pressure is 1250 psia. Pressurizer level is 45%. HPSI injection is 330 gpm/cold leg (acceptable flow). Reactor coolant system is 28°F subcooled. Reactor vessel level monitoring system indicates 100% in plenum and upper head. No reactor coolant pumps are running. Containment temperature and pressure are 195°F and 11 psig, respectively. SIAS, CIAS, MSIS, and CSAS have actuated. A cooldown is in progress using steam generators, both WR levels are 50%. WHICH ONE of the following identifies the action the Control Room Supervisor is to direct concerning high pressure safety injection use?

A. HPSI flow may be throttled until HPSI flow is the same as break flow.
B. Continue maximum injection flow until subcooling is at least 24°F.
C. HPSI flow may be throttled to restore pressurizer level 10 to 70%.
D. Continue maximum injection flow until subcooling is at least 44°F.

Answer 15

Answer: D

Question 16

A loss of coolant accident (LOCA) has occurred. Several seconds after the trip, a lockout of PBA-S03 occurs. RCS pressure is observed to be 550 psia and lowering. Based on these conditions, the expected safety injection would be increasing HPSI flow…

A. to reactor coolant loops 2A and 2B.
B. to all reactor coolant cold legs.
C. and LPSI flow to all reactor coolant cold legs.
D. and LPSI flow to reactor coolant loops 2A and 2B.

Answer 16

Answer: B

Question 17

A LOCA has occurred on Unit 1. Approximately one minute after the Train B Essential Chiller started, a fault locks out PBB-S04. RCS pressure is 750 psig and lowering. Based on this, the expected safety injection would be:

A. increasing HPSI flow into reactor coolant loops 1A and 1B only.
B. increasing LPSI and HPSI flow into all reactor coolant loops.
C. increasing HPSI flow into all reactor coolant loops.
D. increasing LPSI and HPSI flow into reactor coolant loops 1A and 1B only.

Answer 17

Answer: C

Question 18

During an ESD, why should safety injection be throttled as soon as the throttle criteria is met?

A. Minimizes the possibility of pressurized thermal shock.
B. Prevents excessive cooldown.
C. Minimizes erosion damage to the injection valves.
D. Minimizes the time SI pumps are running on mini-flow.

Answer 18

Answer: A

Question 19

Reactor coolant system pressure is 30 psig. A large break, design basis Loss Of Coolant Accident occurred 90 minutes ago. All safety injection systems have been operated as designed. Which one of the following is the suction source for the containment spray pump (assume the operators have performed the required actions)?

A. Spent fuel pool and Recirculation Sump
B. Refueling water tank ONLY
C. Recirculation sump and RWT
D. Recirculation sump ONLY

Answer 19

Answer: D

Question 20

Reactor Tripped 
SIAS 
CIAS 
MSIS 
All equipment is operating as required The Operator places the control switch for SIB-P02 (HPSI Pump) into the START position and then to the STOP position. What effect, if any, will this manipulation have on further pump operation? HPSI pump "B" has been placed into SIAS override ....

A. and stopped, it will now respond to any automatic actuation signals.
B. but will continue to run, unless taken to stop a second time.
C. and stopped, all further starts and stops will have to be done manually.
D. and stopped, it can only be restarted after the SIAS has been reset.

Answer 20

Answer: C

Question 21

Following a Loss of Coolant Accident (LOCA), RCS pressure is at 450 psia and dropping. The expected safety injection indications would be:

A. constant HPSI and LPSI flow.
B. increasing HPSI flow with no LPSI flow.
C. increasing HPSI and LPSI flow.
D. constant HPSI flow with no LPSI flow.

Answer 21

Answer: B

Question 22

A large break LOCA has occurred. Refueling Water Tank (RWT) level is 10% and lowering. SIAS/CIAS/CSAS/MSIS have actuated. No other ESF actuations have occurred. Which ONE of the following actions should the operators take in regards to Recirculation Actuation Signal (RAS)?

A. Manually initiate RAS from Board 5 on trend.
B. Wait until the RWT reaches the RAS actuation setpoint and verify that RAS automatically actuates.
C. Manually initiate RAS from the Aux Relay Cabinets on trend.
D. Trip both Low Pressure Safety Injection Pumps and close all SI pump recirc valves, then manually initiate RAS from B05.

Answer 22

Answer: B

Question 23

The bases for the minimum required volume of the RWT ensures that at the time of RAS initiation the water level in the containment sump will be enough to provide NPSH for the ESF pumps and the decay heat boil-off rate is less than …

A. the minimum design flow of two HPSI pumps and two LPSI pumps.
B. the minimum design flow of two HPSI pumps.
C. the minimum design flow of one HPSI pump and one LPSI pump.
D. 75% of the minimum design flow of one HPSI pump.

Answer 23

Answer: D

Question 24

Reactor power is steady at 99%. Safety Injection Tank (SIT) “1B” indicates the following: 1. Level is 60% narrow range (NR). 2. Boric acid concentration is 2400 ppm. 3. Nitrogen cover pressure is 580 psig. 4. Nitrogen vent valve is closed and de-energized. Which ONE of the following SIT “1B” parameters must be corrected prior to declaring SIT “1B” operable?

A. SIT nitrogen pressure must be > 600 psig.
B. SIT level must be > 70% NR.
C. SIT nitrogen vent valves must be energized.
D. Boric acid concentration must be > 4000 ppm.

Answer 24

Answer: A

Question 25

The reactor has tripped following a LOCA. RCS pressure - 430 psia. RCS temperature - 360°F. Containment Pressure - 10 psig. SIAS/CIAS/MSIS/CSAS have initiated. The primary operator is attempting to align shutdown cooling to the “A” train. SIC-UV-653, RC LOOP 1 to S/D CLG - LPSI PMP “A” suction valve, did not open. Which one of the following current conditions prevents opening this valve?

A. Containment Pressure > 8.5 psig.
B. SIAS signal is present.
C. RCS temperature > 350°F.
D. RCS pressure > 385 psia.

Answer 25

Answer: D

Question 26

According to the ECCS design criteria found in 10CFR “The calculated total oxidation of the cladding shall nowhere exceed _____ % of the total cladding thickness before oxidation.”

A. 17
B. 1
C. 27
D. 35

Answer 26

Answer: A

Question 27

Unit 1 is operating at rated power. LPSI “A” becomes inoperable at 1200 on 10-10. LPSI “B” becomes inoperable at 1800 on 10-15. LPSI “B” is restored to operable status on 2000 on 10-15. Assuming extensions are applied (if applicable), when must LPSI ‘A’ be restored to operable status before further action is required.

A. 1200 on 10-18.
B. 2000 on 10-18.
C. 1200 on 10-17.
D. 1800 on 10-19.

Answer 27

Answer: C

Question 28

In addition to limiting the amount of fission products released, which one of the following describes why it is important to locate and stop a leak in the safety injection piping outside of containment during a large LOCA?

A. A LOCA outside of containment will result in inadequate containment sump inventory to allow recirculation.
B. Prevent safety injection pump runout during the injection phase following a LOCA.
C. Reduces the amount of fixed contamination that will remain in the containment after repair of the leak.
D. Prevent short circuit of the auxiliary building electrical systems with resultant possibility of electric shock.

Answer 28

Answer: A

Question 29

The minimum required volume of the RWT is based on ensuring that by the time of RAS, the water level in the containment sump will be enough to provide NPSH for the ESF pumps and the decay heat boil-off rate is less than…

A. 75% of the minimum design flow of one HPSI pump.
B. the minimum design flow of two HPSI pumps.
C. the minimum design flow of two HPSI pumps and two LPSI pumps.
D. the minimum design flow of one HPSI pump and one LPSI pump.

Answer 29

Answer: A

Question 30

A large break LOCA has occurred. 40EP-9EO03, LOCA is in use. All systems and components have operated as designed. RWT level is 8% on all four channels. What is currently the suction source of the High Pressure Safety Injection pumps?

A. Spent Fuel Pool.
B. Refueling Water Tank.
C. Containment sump.
D. Volume Control Tank.

Answer 30

Answer: B

Question 31

Which one of the following systems is designed to automatically inject water into the Reactor Coolant System during a loss of coolant accident?

A. Containment Spray System.
B. Shutdown Cooling System.
C. Safety Injection System.
D. Essential Chill Water System.

Answer 31

Answer: C

Question 32

SIAS/CIAS has initiated and RCS pressure is currently 400 psia.
RWT Level Channel A reads 9.4%
RWT Level Channel B reads 7.1%
RWT Level Channel C reads 7.0%
RWT Level Channel D reads 7.2%
Which one of the following describes the plant response to the above conditions?

A. Both trains of low pressure safety injection pumps are running.
B. Both trains of low pressure safety injection pumps have tripped.
C. Both trains of high pressure safety injection pumps have tripped.
D. Train A low pressure safety injection pump is running and the Train B high pressure safety injection pump has tripped.

Answer 32

Answer: B

Question 33

With the reactor at 100% power, what is the normal condition of the SIT outlet valves and why are they in that condition?

A. The valves are open and downpowered to maintain it as a passive system.
B. The valves are open and powered up to provide for rapid closure after a SIAS.
C. The valves are closed and powered up to allow the SIAS to automatically open the valves.
D. The valves are closed and downpowered to prevent voiding the RCS with nitrogen after a SIAS.

Answer 33

Answer: A

Question 34

Which one of the following is a function of the Shutdown Cooling System?

A. Refill reactor vessel during ESD events.
B. Provide back up cooling to the Spent Fuel Pool.
C. Remove heat from the Main Steam line post LOCA.
D. Provide back up to the HPSI pumps following a small break LOCA with RCS pressure at > 500 psia.

Answer 34

Answer: B

Question 35

Unit 1 is operating in Mode 5 with SDC in service. The ‘A’ LPSI pump is operating. An inadvertent Train ‘A’ RAS occurs. Based on these conditions, what actions, if any, are necessary to maintain and/or restore the plant to a stable condition?
A. Override and start the ‘A’ LPSI pump and restore SDC to service.
B. No actions should be necessary, since the RAS is only Train ‘A’.
C. Override and open the LPSI injection valves to restore SDC to service.
D. Override and open the minimum recirc valves to restore minimum flow protection for the ‘A’ LPSI pump.

Answer 35

Answer: A

Question 36

Which one of the following systems may be used to augment fuel pool cooling if the nuclear cooling water system can not handle the heat load during refueling?

A. Essential Chill Water system.
B. Containment Spray system.
C. Normal Chill Water system.
D. Shutdown Cooling system.

Answer 36

Answer: D