electricaldist

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electricaldist
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  1. LCO 3.8.2 AC Sources - Shutdown
    • LCO 3.8.2 The following AC electrical power sources shall be OPERABLE:
    • a. One qualified circuit between the offsite transmission network and the onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.10, "Distribution Systems - Shutdown"; and
    • b. One Diesel Generator (DG) capable of supplying one train of the onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.10.

    • APPLICABILITY: MODES 5 and 6,
    • During movement of irradiated fuel assemblies.
    • -----------------NOTE-------------------
    • Enter applicable Conditions and Required Actions of LCO 3.8.10, with one required train de-energized as a result of Condition A.
    • ---------------------------------------------
    • ACTIONS:
    • A. The required offsite circuit inoperable.
    • -A.1 Declare affected required feature(s) with no offsite power available inoperable. IMMEDIATELY
    • OR
    • -A.2.1 Suspend CORE ALTERATIONS. IMMEDIATELY
    • ---AND
    • -A.2.2 Suspend movement of irradiated fuel assemblies. IMMEDIATELY
    • ---AND
    • -A.2.3 Initiate action to suspend operations involving positive reactivity additions. IMMEDIATELY
    • ---AND
    • -A.2.4 Initiate action to restore required offsite power circuit to OPERABLE status. IMMEDIATELY

    • B. The required DG inoperable.
    • -B.1 Suspend CORE ALTERATIONS. IMMEDIATELY
    • AND
    • -B.2 Suspend movement of irradiated fuel assemblies. IMMEDIATELY
    • AND
    • -B.3 Initiate action to suspend operations involving positive reactivity additions. IMMEDIATELY
    • AND
    • -B.4 Initiate action to restore required DG to OPERABLE status. IMMEDIATELY
  2. LCO 3.8.10 Distribution Systems - Shutdown
    LCO 3.8.10 The necessary portion of AC, DC, and Preferred AC bus electrical power distribution subsystems shall be OPERABLE to support equipment required to be OPERABLE.

    • APPLICABILITY: MODES 5 and 6,
    • During movement of irradiated fuel assemblies.

    • ACTIONS:
    • A. One or more required AC, DC, or Preferred AC bus electrical power distribution subsystems inoperable.
    • -A.1 Declare associated supported required feature(s) inoperable. IMMEDIATELY
    • OR
    • -A.2.1 Suspend CORE ALTERATIONS. IMMEDIATELY
    • ---AND
    • -A.2.2 Suspend movement of irradiated fuel assemblies. IMMEDIATELY
    • ---AND
    • -A.2.3 Initiate action to suspend operations involving positive reactivity additions. IMMEDIATELY
    • ---AND
    • -A.2.4 Initiate actions to restore required AC, DC, and Preferred AC bus electrical power distribution subsystems to OPERABLE status. IMMEDIATELY
    • ---AND
    • -A.2.5 Declare associated required shutdown cooling train inoperable and not in operation. IMMEDIATELY
  3. LCO 3.8.8 Inverters - Shutdown
    LCO 3.8.8 Inverter(s) shall be OPERABLE to support the onsite Class 1E Preferred AC bus electrical power distribution subsystem(s) required by LCO 3.8.10, "Distribution Systems—Shutdown."

    • APPLICABILITY: MODES 5 and 6,
    • During movement of irradiated fuel assemblies.

    ACTIONS:

    • A. One or more required inverters inoperable.
    • -A.1 Declare affected required feature(s) inoperable. Immediately
    • OR
    • -A.2.1 Suspend CORE ALTERATIONS. Immediately
    • --AND
    • -A.2.2 Suspend movement of irradiated fuel assemblies. IMMEDIATELY
    • ---AND
    • -A.2.3 Initiate action to suspend operations involving positive reactivity additions. IMMEDIATELY
    • ---AND
    • -A.2.4 Initiate action to restore Required inverters to OPERABLE status. IMMEDIATELY
  4. LCO 3.8.7 Inverters - Operating
    LCO 3.8.7 Four inverters shall be OPERABLE.

    APPLICABILITY: MODES 1, 2, 3, and 4.

    • ACTIONS:
    • A. One inverter inoperable
    • -A.1  Restore inverter to OPERABLE status within 24 hours.

    • B. Required Action and associated Completion Time not met.
    • -B.1 Be in MODE 3 within 6 hours
    • AND
    • -B.2 Be in MODE 5 within 36 hours.
  5. LCO 3.8.4 DC Sources - Operating
    LCO 3.8.4 The Left Train and Right Train DC electrical power sources shall be OPERABLE.

    APPLICABILITY: MODES 1, 2, 3, and 4.

    ACTIONS

    • A. One required DC electrical power source battery charger inoperable.
    • -A.1 Verify functional cross-connected battery charger is connected supplying power to the affected DC train within 2 hours.
    • AND
    • -A.2 Restore required DC electrical power source battery charger to OPERABLE status within 7 days.

    • B. One required DC electrical power source battery inoperable.
    • -B.1 Verify OPERABLE directly connected and functional cross-connected battery chargers are connected supplying power to the affected DC train within 2 hours.
    • AND
    • -B.2 Restore required DC electrical power source battery to OPERABLE status withing 24 hours.

    • C. Required Action and associated Completion Time not met.
    • -C.1 Be in MODE 3 within 6 hours
    • AND
    • -C.2 Be in MODE 5 within 36 hours.
  6. LCO 3.8.1 AC Sources - Operating
    • LCO 3.8.1 The following AC electrical sources shall be OPERABLE:
    • a. Two qualified circuits between the offsite transmission network
    • and the onsite Class 1E AC Electrical Power Distribution System;
    • and
    • b. Two Diesel Generators (DGs) each capable of supplying one train
    • of the onsite Class 1E AC Electrical Power Distribution System.

    • APPLICABILITY: MODES 1, 2, 3, and 4.
    • -------------NOTE---------------------------
    • LCO 3.0.4.b is not applicable to DGs.

    • ACTIONS:
    • A. One offsite circuit
    • inoperable.
    • -A.1 Perform SR 3.8.1.1
    • (offsite source check)
    • for OPERABLE offsite
    • circuit. 1 HOUR AND once per 8 hours thereafter
    • AND
    • -A.2 Restore offsite circuit to OPERABLE status within 72 hour AND 10 days from discovery of failure to meet LCO

    • B. One DG inoperable.
    • -B.1 Perform SR 3.8.1.1
    • (offsite source check)
    • for the OPERABLE
    • offsite circuit(s). 1 HOUR AND once per 8 hours thereafter
    • AND
    • -B.2 Declare required features supported by the inoperable DG inoperable when its redundant required feature(s) is inoperable.  4 hours from discovery of Condition B concurrent with inoperability of redundant required feature(s)
    • AND
    • -B.3.1 Determine OPERABLE DG is not inoperable due to common cause failure within 24 hours
    •        OR 
    • -B.3.2 Perform SR 3.8.1.2 (start test) for OPERABLE DG within 24 hours.

    • AND
    • -B.4 Restore DG to OPERABLE status within 7 days and 10 days from discovery of failure to meet LCO

    • C. Two offsite circuits inoperable
    • -C.1 Declare required features inoperable when its redundant required features are inoperable within 12 hours of discovery of Condition C concurrent with inoperability of redundant required features
    • AND
    • -C.2 Restore one offsite circuit to OPERABLE status within 24 hours.

    • D. One offsite circuit inoperable AND one DG inoperable.
    • -D.1 Restore offsite circuit to OPERABLE status within 12 hours
    • OR
    • -D.2 Restore DG to OPERABLE status within 12 hours

    • E. Two DGs inoperable 
    • -E.1 Restore one DG to OPERABLE status within 2 hours.

    • F. Required Action and Associated Completion Time of Condition A, B, C, D, or E not met.
    • -F.1 Be in MODE 3 within 6 hours
    • AND
    • -F.2 Be in MODE 5 within 36 hours
    • G. Three or more AC sources
    • inoperable.
    • -G.1 Enter LCO 3.0.3. IMMEDIATELY
  7. LCO 3.8.9 Distribution Systems - Operating
    LCO 3.8.9 Left Train and Right Train AC, DC, and Preferred AC bus electrical power distribution subsystems shall be OPERABLE.

    APPLICABILITY: MODES 1, 2, 3, and 4.

    • ACTIONS:
    • E. Two or more inoperable distribution subsystems that result in a loss of function.
    • -E.1 Enter LCO 3.0.3. IMMEDIATELY
  8. LCO 3.8.6 Battery Cell Parameters
    LCO 3.8.6 Battery cell parameters for the Left Train and Right Train batteries shall be within limits.

    • APPLICABILITY: When associated DC electrical power source(s) are required to be OPERABLE.
    • -------------NOTE---------------------------
    • Separate Condition entry is allowed for each battery.

    • ACTIONS:
    • A. One or more batteries with one or more battery cell parameters not within Category A or B limits.
    • -A.1 Verify pilot cells electrolyte level and float voltage meet Table 3.8.6-1 Category C limits. 1 HOUR
    • AND
    • -A.2 Verify battery cell parameters meet Table 3.8.6-1 Category C limits.  24 HOURS AND once per 7 days thereafter
    • AND
    • -A.3 Restore battery cell parameters to Category A and B limits of Table 3.8.6-1.  31 DAYS
    • B. Required Action and associated Completion Time of Condition A not met.
    • OR
    • One or more batteries with average electrolyte temperature of the representative cells < 70°F.
    • OR
    • One or more batteries with one or more battery cell parameters not within Category C limits.
    • -B.1 Declare associated battery inoperable. IMMEDIATELY
  9. What is the operational design of the electrical buses?
    2 buses (front and rear), 6 transmission lines connect the switchyard to the grid with 2 circuits on each of 3 towers, each line has the capacity to carry the entire output of the main generator
  10. Given the plant shutdown and a request to remove a startup transformer from service, what actions must be taken to maintain 4160V buses energized?
    • You must backfeed through the main transformer
    • You must open MOD-389
  11. What is the design basis of the 125 VDC system?
    • Provides a continuous DC power source during disturbances in the auxiliary power system
    • Allows for reliable plant operation by providing a continous DC power source for instruments and controls whose loss could cause unnecessary plant trips
    • Provides a continous DC power source during DBA's
  12. ORM 3.7.11 Electrical power systems operating
    • Spec:
    • 2400 V bus 1E shall be operable

    • APP: Modes 1-4
    • -restore to operable within 24 hours
  13. LCO 3.8.5 DC Sources - Shutdown
    LCO 3.8.5 DC electrical power source(s) shall be OPERABLE to support the DC electrical power distribution subsystem(s) required by LCO 3.8.10, "Distribution Systems—Shutdown."

    • APPLICABILITY: MODES 5 and 6,
    • During movement of irradiated fuel assemblies.

    • ACTIONS:
    • A. One or more required DC electrical power sources inoperable.
    • -A.1 Declare affected required feature(s) inoperable. IMMEDIATELY
    • OR
    • -A.2.1 Suspend CORE ALTERATIONS. IMMEDIATELY
    • ---AND
    • -A.2.2 Suspend movement of irradiated fuel assemblies. IMMEDIATELY
    • ---AND
    • -A.2.3 Initiate action to suspend operations involving positive reactivity additions. IMMEDIATELY
    • ---AND
    • -A.2.4 Initiate action to restore required DC electrical power source(s) to OPERABLE status. IMMEDIATELY
  14. What is the design basis of the station batteries?
    • The station batteries must supply emergency loads for 4 hours until offsite or onsite power is restored.
    • In the event of a cable spreading room fire, to provide 72 hours of unsupported DC power to achieve plant cold shutdown
  15. What is the design basis of the 120V preferred AC power system?
    • Supply uninteruptible AC power to the preferred AC buses at a sufficient power level to support both normal and emergency loads.
    • Supply the required loads independent of disturbances in the offsite AC system
  16. What is the purpose of the electrical distribution system?
    • Supply and distribute electrical power needed to preserve the 3 fission product barriers:
    • -fuel cladding
    • -primary coolant system
    • -containment building
    • under all plant conditions, including emergencies
  17. How does degraded grid voltage effect the electrical distribution system?
    • Load tap changers correct undervoltage
    • Can cause undervoltage trips
  18. During a plant startup(shutdown), describe the potential consequences of failing to transfer from startup(shutdown) to station(startup) power?
    You would lose your coastdown feature on the PCPs
  19. How do transformer tap settings impact the operation of the electrical distribution system?
    Variations in grid voltages are corrected by an automatic load tap changer on the safeguards transformer low side.
  20. What are the power supplies for the NSD and DBA sequencers?
    • Y-20
    • Y-30
  21. ORM 3.7.12 Electrical power systems-shutdown
    • SPEC:
    • AC sources, DC sources, inverter, AC bus, DC bus, or preferred AC bus requirements of Tech specs shall be operable

    App: Modes 5 and 6 and during movement of irradiated fuel assemblies

    • Actions:
    • 3.7.12.a : one or more required AC source, DC source, inverter, AC bus, DC bus or preferred AC bus inoperable
    • -suspend crane operations over irradiated fuel IMMEDIATELY
    • AND
    • -suspend operations with a potential for draining the PCS or the SFP IMMEDIATELY
  22. What effect will disconnecting battery #1 and D-11A have on the overall electrical distribution system?
    • Potential loss of DC bus 1 on loss of AC power
    • Potential loss of D/G 1-1
    • Loss of control power to LCC-13 and LCC-14 and C-150 remote shutdown panel
    • Loss of control power to C bus
  23. What is the effect on the emergency Diesel Generator System due to a loss of DC Bus 11A?
    Loss of control power to Diesel Generator 1-1 and Loss of Bus 1C control power. Incoming breakers
  24. What happens on a fault of the R bus?
    • 1) Primary (487B-P/R) - R Bus Differential isolates R bus (trips R bus breakers and initiates a transfer trip to trip all S/U xfmr low side breakers
    • 2) Zone of Protection - From each R bus breaker to high side of each S/U xfmr
    • 3) Operates aux relay (486S-X) which initiates a transfer trip to trip all S/U xfmr low side breakers).
    • 4) Backup (487B-B/R) - same function as primary
  25. What happens on a fault on the F bus, S/G 1-1, or cabling to 152-401?
    • 1) Primary scheme (487B-P/F) - initiated by bus differential voltage and S/G transformer differential current and ground relays.
    • 2) Backup scheme (487B-B/F) - initiated S/G transformer overcurrent and sudden pressure relays, Load Tap Changer Pressure relief Device and LTC hand crank removal.
    • 3) Relays initiate:
    • a) Trip of F bus breakers
    • b) Trip of Safeguards Bus Feeder breaker152‑401
    • c) Fast transfer of 2400V busses to S/U 1-2
  26. What happens on a Fault on Safeguards and Line between Safeguards Bus to 2400V Buses?
    • 1) Differential relays (187-1)
    • 2) Trips 152‑401 or 152‑402 breaker
    • 3) Initiates fast transfer of 2400V Busses when 152‑401 is closed.
    • 4) If 152-402 is closed and fails to trip open when this differential relay operates, a breaker failure relay on this breaker will detect this and will initiate a unit trip.
  27. What happens on a fault on Main Xfmr 1-1?
    • 1) Differential protection (487U) (C04 panel)
    • a) Zone of Protection - Main Xfmr, Main Gen., and high voltage of S/P 1-1 and 1-2
    • b) Operates the 386B lockout relay which trips Main Gen.
    • 2) Sudden Pressure (463M)
    • a) Detects a sudden rise in gas pressure caused by a fault internal to the xfmrs.
    • b) Aux relay 463MX actuates 386P (plant trip).
    • c) Aux relay 463XX causes an alarm and actuates deluge system.
    • 3) Ground Protection (451MN)
  28. What happens on a fault on Line between Main Xfmr and SWYD?
    Trips the main generator, and their output breakers open.
  29. What types of faults and what happens on a fault on the Station Power Transformers?
    • 1) Differential
    • a) S/P Xfmr 1-1 - (287)
    • b) S/P Xfmr 1-2 - (187)
    • c) S/P Xfmr 1-3 - (487-SP3)
    • d) Zone of Protection - From to low side of station power breakers.
    • e) Actuates 386B (plant trip)
    • 2) Sudden Pressure
    • S/P 1-2 (163), S/P 1-1 (263), S/P 1-3 (463) will operate a 163X, 263X, 463FPX aux. relay, which initiates:
    • a) Deluge system
    • b) Alarms
    • c) Actuates the 386P relay.
    • 3) S/P Xfmr 1-2
    • With the 152‑402 closed a fault will trip the plant. 2400 V buses will transfer to S/U power
  30. What happens on a fault on S/U Transformers?
    Opens all R bus breakers, and S/U low side breakers (incoming breakers to busses from S/U transformers)
  31. What happens on a S/U transformer Sudden Pressure (SP463-S1, SP463-S2, SP463‑13)?
    Trips R Bus, trips all S/U Xfmr low side breakers, and actuate deluge valve.
  32. What kind of ground protection do we have for the Startup transformers?
    • 1) Each xfmr is equipped with one ­overcurrent relay connected to the 345 KV side of each xfmr (451‑SN1, 451-SN2, 451-SN3).
    • 2) Trips R Bus and trips all S/U Xfmr low side breakers.
  33. What protections do we have for a fault on a 4160V Bus?
    • 1) Overcurrent
    • a) Each 4160V incoming breaker has phase time overcurrent relays and one ground time overcurrent relay to protect against switchgear bus faults and to provide backup protection for feeder circuit faults.
    • b) When supplied from S/U transformer Buses 1A and 1B overcurrent relay trip their associated incoming breaker.
    • c) When supplied from S/U transformer Busses 1F and 1G overcurrent relays (251-3 & 251‑4) and ground relays (25IN-3 & 25IN-4) trip their associated incoming breaker.
    • d) When supplied from S/P transformer Buses 1A and 1B overcurrent relay (251-101 & 251‑201) trip their associated incoming breaker, block fast transfer and block manual closure.
    • e) When supplied from S/P transformer Buses 1F and 1G overcurrent relays (251-1 & 251‑2) and ground relays (25IN-1 & 25IN-2) trip their associated incoming breaker, block fast transfer and block manual closure.
    • 2) Undervoltage
    • a) Each bus has inverse time undervoltage relay (227-1, 227‑2, 227-3, 227-4) that trips PCPs, Cooling Tower Pumps and condensate pumps to prevent damage to the motors.
    • b) Relays on breakers 252-101 and 252-201, 252-301, 252-401 actuate a lockout relay to trip and lockout the incoming breaker, and prevent a fast transfer to the start-up transformer. The purpose for this is to prevent connecting a source of supply to a faulted bus.
  34. What happens on an overcurrent condition on a 2400V Bus?
    • 1) Overcurrent
    • a) Phase overcurrent relays protect against switchgear bus faults and to provide backup protection for feeder circuit faults.
    • b) In the event of a 2400V bus fault, relays on Breakers 152‑105, 152-203 and 152-302 (incoming breakers from the Safeguard Bus) actuate a lockout relay to trip and lockout the incoming breaker, D/G output breaker will not close. The basis for this is to prevent connecting a source of supply to a faulted bus.
    • c) 2400V AC breakers supplying motors have overcurrent relays (protect against overload, locked rotor and faults). Actuation of the relay isolated the faulted motor from the 2400V bus.
  35. What protection do we have against grounds on a 2400V Bus?
    • 1) Ground Detection Relay (164)
    • a) Ground relays are not used for system protection in the 2400V AC distribution system since this is an ungrounded system. However, ground relays are used to alarm and indicate the existence of a ground fault on the 2400V AC system.
    • b) Ground Detection Lights are mounted adjacent to the relay.
    • (1) Normally dimly lit.
    • (2) In the case of a ground on the bus, the intensity of the lights would vary.
    • (3) Alarms only
  36. What happens on an undervoltage condition on our 2400V Busses?
    • 1) Undervoltage
    • a) First Level (127-1, 2)
    • (1) Trip respective incoming bus breakers
    • (2) Initiates load shedding (D/G breaker must be open).
    • (3) Starts respective diesel
    • (4) Set at 77% of rated voltage with an inverse time relay. This means that if the bus voltage were to degrade to 70%, the time it would take for the relay to operate would be longer than if the voltage were to drop to 10 % in the same time period. The greater the voltage drop, the quicker the relay response. Protects against a sudden loss of voltage as sensed on the bus.
    • b) Second Level Under voltage Protection (127‑7, 8)
    • (1) Set at 93% of rated voltage. Protects against sustained degraded voltage conditions on the bus.
    • (2) When under voltage condition exists for 0.65 second, they initiate a Diesel Generator start. This short time delay set to actuate on voltage dips below normal motor starting voltage. The time delay prevents spurious trips due to momentary voltage dips.
    • (3) If under voltage continues for an additional six seconds a load shed occurs and the Diesel breaker closes. The NSD or DBA sequencer then sequences on loads. The purpose of the time delay is to allow the bus voltage to recover from transients. Relays are mounted in the cabinet adjacent to buses 1C and 1D.
    • c) First and Second Level UV relays initiate reset of the SW, CCW, and LPSI pump STANDBY auto start feature. Prevents closing the pump breaker onto a dead bus and ensures that the sequencer will restore loads in a controlled manner.Signal exists for the duration of any dead bus condition, and clears when bus voltage is restored. With the offsite feeder breaker control switch in "Close" this signal is bypassed. Allows re-energization of the bus to clear the load shed signal. Without this bypass, you would never be able to reenergize the bus.
  37. Which 4160 and 2400 VAC S/U and S/P incoming breakers require that the sync check relays be made up before a manual close of the incoming breaker is possible?
    ALL
  38. Why must the sync check switch be made up to close 4160 and 2400 VAC S/U and S/P incoming breakers?
    The synch check ensures that power sources are in phase prior to synchronizing.
  39. What breaker permissives that must be met in order to close a 4160 or 2400 VAC S/U and S/P incoming breaker?
    • No faults on the transformer that will be supplying power.
    • * The feeder breaker you are getting ready to close must be open. (This may sound odd, but it is a permissive.
    • * Breaker closing springs charged.
    • * Sync check relay (sync switch engaged).
  40. A spurious turbine trip has caused a reactor trip. All systems are functioning normally; all offsite power sources are available and the safeguards bus is energized. What would be the impact on Bus 1C if breaker 152-105 were to be MANUALLY opened under these conditions?
    D/G 1-1 start logic will recognize Bus 1C as de-energized with no faults, start and close breaker 152-107 and sequence on loads.
  41. The plant is at 50% power. Bus 1A is being transferred from S/P Xfmr 1-1 to S/U Xfmr 1-1. The following indications are present:
    S/U breaker: GREEN and WHITE lights lit
    S/P breaker: Red and WHITE lights lit
    The following then occurs:
    1] Incoming breaker from S/P opens when incoming breaker from S/U is closed.
    2] RED light on S/U incoming breaker is lit and WHITE light is off.
    3] GREEN and WHITE lights are lit on S/P incoming breaker.
    [Per SOP-30 if the white light for the incoming breaker (from S/U) is not lit power is to be transferred back to the original source (in this case the S/P transformer)].
    d] After power is transferred back to the S/P transformer the station power transformer differential relay actuates
    Describe the plant’s response.
    With the S/U incoming breaker OPEN (with transferring back, S/U breaker would be open with no WHITE light) and the white light out the closing springs are not charged and the S/U breaker will not reclose until the springs are manually recharged. This breaker will not close on fast transfer. The station power transformer differential relay will cause a fast transfer that will initiate a turbine and reactor trip. Bus 1A will be de-energized and P-50A/C will trip. With the white light out, the breaker can be tripped (locally), but not reclosed.
  42. What do you lose on a SIS load shed?
    E bus, LCC 77, P-40A Dilution water pump.
  43. What are the qualified offsite power sources?
    Safeguards bus, Startup 1-2 in modes 1-4, in modes 5, 6 station power 1-2 is considered qualified based on the fact that redundancy is not required in these modes.

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