Diesel Generator Flashcards
Unit 1 is at 100% power with all systems in a normal lineup.
NAN-S03A, the supply breaker to NBN-X03, tripped open on a ground fault, de-energizing PBA-S03.
PBA-S03L, normal supply breaker for PBA-S03, is closed.
PBA-S03K, alternate supply breaker for PBA-S03, is open.
PBA-S03B, ‘A’ DG output breaker, is open.
‘A’ DG is running at 60 Hz and 4200 V.
Which of the following actions should be taken to restore power to PBA-S03?
A. Place PBA-HS-S03L (normal supply breaker) to OPEN.
B. Place PBA-HS-S03K (alternate supply breaker) to CLOSE.
C. Place PEA-HS-S03B (DG output) to CLOSE.
D. Place PEA-HS-S03B (DG output) to OPEN, then to CLOSE.
A
Unit 3 was at 100% power with all systems in a normal lineup.
A feed line break caused the control room to trip the reactor and initiate MSIS.
Ten minutes later, AFAS-1 and AFAS-2 are actuated due to low Steam Generator level.
‘A’ DG HI PRIORITY TRBL alarm is received due to high jacket water temperature.
Based on these conditions, ‘A’ DG is currently ___(1)___. If the DG Control Switch DGA-HS-1 is placed in START, ___(2)___.
A. (1) in standby; (2) the DG will start.
B. (1) tripped; (2) the white OVERRIDE light will come on and the DG will not start.
C. (1) running; (2) the white OVERRIDE light will come on.
D. (1) running; (2) the white OVERRIDE light will remain dark.
C
Unit 3 was at 100% power with all systems in a normal lineup.
A feed line break in the turbine building caused the control room to trip the reactor and initiate MSIS.
‘A’ DG LO PRIORITY TRBL alarm is received due to low starting air pressure in the ‘B’ air receiver.
Based on these conditions, ‘A’ DG is currently ___(1)___. If the DG Control Switch DGA-HS-1 is placed in START, ___(2)___.
A. (1) in standby; (2) the DG will start.
B. (1) tripped; (2) the white OVERRIDE light will come on and the DG will not start.
C. (1) running; (2) the white OVERRIDE light will come on.
D. (1) running; (2) the white OVERRIDE light will remain dark.
A
State the DG out put ratings and limitations.
5500 KW continuous output, and up to 6050 KW output for 2 hours out of 24 hours.
State the DG start signals and time requirement.
Each diesel generator automatically starts and is capable of being loaded within 10 seconds following receipt of:
SIAS
AFAS
LOP
CSAS (DG not in Emergency Run unless SIAS present also)
At what speed does the Overspeed Shutdown Butterfly Valve trip?
It is tripped by the overspeed governor at 660 rpm. When tripped, it isolates the combustion air source to the turbocharger and therefore shuts down the engine. The overspeed trip is one of the emergency run trips and is the only direct mechanical automatic trip that will trip the DG during a loss of control air.
State how the Essential Spray Pond supports the Emergency Diesel Generators.
The associated Spray Pond pump automatically starts when the DG starts and provides water to cool the jacket water, lube oil, fuel oil and intercooler heat exchangers.
Without the (SP) system the DG must be secured within:
• 15 minutes unloaded
• 2.6 minutes fully loaded
- Emphasize that if no SP pump is running, the RO must contact an AO to Emergency Stop the DG.
State the minimum Fuel Oil Storage Tank level allowed per LCO 3.8.3.
The minimum allowable level (TS 3.8.3) is ≥80% based on providing sufficient fuel for 7 days of continuous operation at 100% rated output. It is administratively controlled at ≥ 85%.
At levels <71%, declare the DG inoperable.
State the minimum level allowed in the Fuel Oil Day Tank.
Minimum level is 2.75’ (550 gallons) which provides a 60 minute fuel supply at full rated load on the DG.
When does the DG Essential HVAC start?
The essential DG HVAC will start automatically upon start of the associated diesel generator (the units are started by the ESFAS load sequencer 25 seconds after DG starts).
• The DG control equipment room essential AHU is slaved to the essential exhaust fan and will start when the exhaust fan starts.
• Both units will continue to run until the Diesel Generator is shutdown and their respective room temperature is < 110°F.
State LCO 3.8.3 requirements for Lube Oil.
LCO 3.8.3 requires 2.5” visible in the site glass. If level is <1” then declare the DG inop.
State the Air Receiver design capabilities and LCO 3.8.3 requirements.
Each air receiver, when pressurized to a nominal pressure of 250 psig, contains sufficient air to complete five consecutive engine starts without regard to starting time.
If pressure is <185# then declare the DG inop.
When the overspeed governor senses _______ rpm, it trips which two valves?
660 rpm, The overspeed governor mechanically trips the butterfly valve UV-238 closed via the attached cable. It also trips the adjacent fuel shutoff valve UV-240. Both valves must be manually reset.
How many operators does it take to reset the butterfly valve?
It takes two operators. One operator has to adjust the overspeed governor actuating arm while the other operator aligns and re-latches the butterfly valve trip mechanism.
