EDG

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Author:
heidin
ID:
156332
Filename:
EDG
Updated:
2012-05-29 16:20:13
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Diesel Generators ILC
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  1. Unit 2 is operating at rated power. DG#1 is loaded to 3100 KW for a monthly load test. The following transient occurs on Unit 2:

    Main Generator lockout due to UAT phase overcurrent
    BOP Bus 2D auto transfers to the SAT
    BOP Bus 2C fails to transfer (UAT breaker trips, SAT breaker fails to close)

    DG#1 output breaker will:

    A. Trip and DG#1 will trip on overspeed.
    B. Trip and DG#1 will run unloaded at 60 Hz.
    C. Trip and DG#1 will run unloaded at >60 Hz.
    D. Remain closed and in parallel with the BOP Bus.
    D. Remain closed and in parallel with the BOP Bus.
  2. During performance of PT-12.2C, Diesel Generator #3 (DG3) has tripped on reverse power due to misoperation of the governor control switch. The engine lockout relay and the generator lockout relay (86DB) have tripped.

    A loss of off-site power then occurs. What operator action is necessary to start DG3 following the loss of off-site power?

    A. Reset the engine lockout, then the generator lockout (86DB). The DG will then start with no other operator action required.
    B. Reset the generator lockout (8608), then the engine lockout. The DG will then start with no other operator action required.
    C. Reset the engine lockout, then the generator lockout (86DB). The DG will then start only if Emergency Start (local) or Auto Start (RTGB) is depressed.
    D. Reset the generator lockout (86DB), then the engine lockout. The DG will then start only if Emergency Start (local) or Auto Start (RTGB) is depressed.
    B. Reset the generator lockout (8608), then the engine lockout. The DG will then start with no other operator action required.


    The engine lockout will attempt one reset when the LOOP occurs but will immediately re-trip since the generator lockout is tripped. Since the generator lockout trips the engine lockout, it must be reset first. Once both lockouts are reset, the engine start relays will energize and the engine will start.
  3. Unit One Nuclear Service Water (NSW) pumps are aligned as follows:

    NSW 1A Running in Auto
    NSW 1B In Manual not running (in preparation for pump starting)

    Off-site power is lost. How will NSW pumps 1A and 1B respond when the DGs re-energize their E Buses?

    A. NSW Pumps 1A and 1B will start five seconds after the DGs energize their E Buses.
    B. NSW Pumps 1A and 1B will start immediately when the DGs energize their E Buses.
    C. NSW Pumps 1A will start five seconds after the DGs energize their E Buses. NSW Pump 1B will not auto start.
    D. NSW Pumps 1A will start immediately when the DGs energize their E Buses. NSW Pump 1B will not auto start.
    B. NSW Pumps 1A and 1B will start immediately when the DGs energize their E Buses.


    • NSW Pumps sequence on in 5 seconds if a LOCA signal (and bus has power) is
    • present and immediately (when bus undervoltage clears) after a LOOP without aLOCA. Auto start on both LOOP and LOCA is independent on Mode switch position.
  4. Following a Unit One Loss of Off-Site Power, Emergency Bus E1/DG1 conditions are:

    DG-1 Auto-Start Alarm sealed in
    DG-1 Running Alarm sealed in
    DG-1 Loaded Light is out
    DG-1 No Load Light is lit
    Bus E1 Undervoltage Alarm sealed in

    What could cause of the above indications?

    A. DG1 failed to reach rated speed.
    B. DG1 failed to reach rated voltage.
    C. CSW pump 2C breaker failed to trip on undervoltage.
    D. Substation E5 feeder breaker failed to trip on undervoltage.
    C. CSW pump 2C breaker failed to trip on undervoltage.


    For a DG breaker to close either automatically or manually, the breaker logic must sense the DG at rated speed and voltage. The running alarm and no load light indicate rated speed and voltage have been achieved. For auto closure, the logic must sense the bus is stripped with the exception of the 480 VAC substation feeder breaker. If CSW pump 2C (fed from Bus E1) failed to trip on undervoltage, this permissive is not met, and the breaker will not close.
  5. During accident conditions, the following sequence of events occurs:

    T= 0 seconds Drywell pressure rises above the scram setpoint
    T= 4 seconds Off-site power is lost
    T= 5 seconds Reactor pressure drops below 410 psig
    T= 14 seconds Diesel Generators energize their respective E Buses
    T= 16 seconds Reactor level drops below LL3

    The Core Spray Pumps will auto start at:

    A. T = 20 seconds.
    B. T = 24 seconds.
    C. T = 29 seconds.
    D. T = 31 seconds.
    C. T = 29 seconds.


    Sequential timing relays start 10 second time delay when LOCA signal present and E Bus has voltage. LOCA signal at T = 5 (if bus was energized, pump would start at T= 20). Bus energized at T = 14 so sequential timing relays time out at T = 24 (this starts RHR and initiates additional 5 second TD in Core spray logic. Core spray pump starts when additional 5 seconds elapses (T = 29). If LOCA signal had not previously sealed in, LL3 would initiate the sequence at T =16 for a pump start of T = 31.
  6. Unit 2 is operating at rated power. DG#1 is loaded to 3100 KW for a monthly load test. The following transient occurs on Unit 2:

    Main Generator lockout due to UAT phase overcurrent
    BOP Bus 2D auto transfers to the SAT
    BOP Bus 2C fails to transfer (UAT breaker trips, SAT breaker fails to close)

    DG#1 output breaker will:

    A. Trip and DG#1 will trip on overspeed.
    B. Trip and DG#1 will run unloaded at 60 Hz.
    C. Trip and DG#1 will run unloaded at >60 Hz.
    D. Remain closed and in parallel with the BOP Bus.
    D. Remain closed and in parallel with the BOP Bus.
  7. Which one of the following Loss of Off-site Power (LOOP) signals is defeated by placing the 2D-AD5-SS-43BF keylock switch at 4 KV Switchgear 2D Compt.AD5, in BACKFEED?

    A. SAT Undervoltage (27SX)
    B. Main Generator Primary Lockout (86GP)
    C. Transformer Bus Primary Lockout (86TB)
    D. Main Generator Differential Lockout (86G)
    A. SAT Undervoltage (27SX)
  8. Unit 1 is in MODE 3.
    Unit 2 is at 100% RTP.

    Testing of Diesel Generator # 1 (DG-1) at 2850 KW is in progrss per 0PT-12.2A, No 1 Diesel Generator Monthly Load Test.

    Bus 2C trips off due to a fault condition. How does this event affect the diesel generators?

    A. DG-1 is running loaded.
    DG-2 is running unloaded.
    DG-3 is not running.
    DG-4 is running unloaded.

    B. DG-1 is running loaded.
    DG-2 is not running.
    DG-3 is not running.
    DG-4 is running loaded.

    C. DG-1 is running unloaded.
    DG-2 is not running.
    DG-3 is running loaded.
    DG-4 is not running.

    D. DG-1 is running unloaded.
    DG-2 is not running.
    DG-3 is not running.
    DG-4 is running loaded.
    • B. DG-1 is running loaded.
    • DG-2 is not running.
    • DG-3 is not running.
    • DG-4 is running loaded.


    DG-1 is already loaded for testing and will not be affected by this event. Since Unit 2 UAT is available, a divisional start of the Diesel Generators will not occur. E4 will deenergize causing DG-4 to auto-start and load onto E4.
  9. Unit Two (2) is performing startup per GP-03. The Main Turbine has just been rolled to 1800 RPM per OP-26. Generator startup per OP-27 has not yet been performed.

    BOP Bus 2C trips and locks out due to fault. The Main Turbine does not trip and the Reactor does not scram.

    The operator should verify:

    A. DG3 only is running
    B. DG4 only is running
    C. DG1 and DG3 are running
    D. DG2 and DG4 are running
    D. DG2 and DG4 are running


    • A EDG auto start signal will be generated for EDGs 1 and 3 (2 and 4) if any one of the following conditions exists (Figure 39-13):
    • · Loss of 1C or 2C 4160 BUS will cause EDGs 2 & 4 to start
    • · Loss of 1D or 2D 4160V BUS will cause EDGs 1 & 3 to startThe loss of BOP bus is sensed by undervoltage on the secondary side of the UAT with the UAT to D(C) bus breaker open OR undervoltage on the secondary side of the SAT with the SAT to D(C) bus breaker open AND BOP bus undervoltage. (SD-39)
  10. Unit Two is operating at rated power when the following alarms are received:

    DG-4 CTL POWER SUPPLY LOST
    DG-4 LO START AIR PRESS
    DG4/E4 ESS LOSS OF NORM POWER
    DG-2 CTL POWER SUPPLY LOST

    Subsequently, DG4 control power was transferred to its alternate DC source.

    Which one of the following identifies the DC panel that was lost and the impact on the operability of DG4 in accordance with LCO 3.8.1, AC Sources Operating and LCO 3.8.7, Distribution Systems - Operating?


    A. 125V DC Distribution Panel 1B;
    DG4 is operable on its alternate source for up to 7 days.

    B. 125V DC Distribution Panel 1B;
    DG4 must be declared inoperable the entire time it is on its alternate source.

    C. 125V DC Distribution Panel 2B;
    DG4 is operable on its alternate source for up to 7 days.

    D. 125V DC Distribution Panel 2B;
    DG4 must be declared inoperable the entire time it is on its alternate source.
    C. 125V DC Distribution Panel 2B; DG4 is operable on its alternate source for up to 7 days.


    • Alarms on DG4 indicate that loss is from 2B. Alarm on DG2 is from alternate supply being lost. Tech
    • specs give you 7 days to fix while you are on alternate, during this time it is operable.

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