EC (Essential Chilled Water) Flashcards
Unit 1 has tripped due to a LOCA. The crew is responding to the emergency. Offsite power is available and presently powering the Class 1E buses. The ‘B’ Essential Cooling Water pump trips. Shortly after this, the Operating Crew notices that the ‘B’ Essential Chiller has tripped. Based on these conditions, the ‘B’ Essential Chiller most likely tripped on…
A. low EW flow.
B. high condenser pressure.
C. low chill water temp.
D. low refrigerant temperature.
Answer: B
EC Train has been declared inoperable due to a pump failure. What is the Maximum Out of Service Time for CREATCS as determined by the SafetyFunction Determination Procedure. (Assume CREATCS is inoperable solely due to its support system EC being inoperable)
A. 144 hours
B. 72 hours
C. 792 hours
D. 720 hours
Answer: C
A SIAS has occurred due to a LOCA. All ESF equipment has started as expected. Five minutes after the SIAS, the ‘A’ EW pump trips. Based on these conditions, the ‘A’ Essential Chiller will…
A. immediately trip on low EW flow.
B. shutdown on low-load recycle.
C. trip on high condenser pressure.
D. not be impacted, since all protective trips are disabled after a SIAS.
Answer: C
The Reactor Operator has been directed to start the “A” train essential chiller from the control room. The last time it was operated was six days ago to support surveillance testing on the steam-driven auxiliary feedwater pump. Which ONE of the selections listed below correctly describes the sequence of events that should be observed, in the control room, when the control switch is positioned to “START”?
A. After an approximate twenty minute time delay, the compressor motor starts and the ammeter indicates starting current. Motor current then decreases to compressor load demand, and finally settles out at steady load rating.
B. After an approximate two minute time delay, the compressor motor starts and the ammeter steadily increases until the compressor is fully loaded.
C. After an approximate one minute time delay, the chilled water pump starts and the pump ammeter indicates starting current. Motor current then decreases to steady load rating.
D. After an approximate one minute time delay, the compressor motor starts with red “RUN” light indication and the ammeter indicating starting current. Motor current then decreases to compressor load demand, and finally settles out at steady load rating.
Answer: D
Which of the following describes the preferred method for starting the Essential Chiller Chilled Water Pump WITHOUT starting the rest of the Essential Chiller Package?
A. Open the disconnect switch on the Auxiliary Power Panel located adjacent to the chiller then take the Control Room hand switch to start.
B. Local hand switch for the Chilled Water Pump located at the Essential Chiller skid.
C. Close the Motor Control Center Breaker locally.
D. Start pushbutton located on the associated Motor Control Center
D. Start pushbutton located on the associated Motor Control Center
(Note: Preferred Method)
Which of these is the ONLY Essential Chilled Water load on which the Chilled Water flow is thermostatically controlled?
A. Electrical Penetration Room ACUs
B. ESF Switchgear Room Essential AHUs
C. CEDM Control Cabinet Room ACUs
D. Control Room Essential AFUs
D. Control Room Essential AFUs
