Class 4.16KV (PB) Flashcards
What is the meaning for “Class 1E” ?
Safety classification for electrical equipment that are needed for safe emergency reactor shutdown
What is the meaning of “Train”?
Independent arrangement of equipment, devices and components available for safe shutdown
Meaning of “Load Group”?
Arrangement of buses, transformers, switching equipment, and loads fed from common power supply
What happens if you have degraded or loss of voltage on Class 4.16kv buses ?
Sends a Loss of Power( LOP) signal to Engineered Safety Features Actuation system
What is considered a blackout ?
Loss of offsite power & loss of both emergency diesel generators
Where does PBA-S03 & PBB-S04 receive its control power from ?
PBA-S03: PKA-D21
PBB-S04: PKA-D22
Can 86 lockout be reset locally and remotely on PBA-S03 & PBB-S04?
Yes
Why would you want to manually actuate an 86 lockout on a class 4.16kv breaker ?
To prevent breaker from closing due to load sequencing signal & allows control room to close it remotely whenever they’re ready
What is the normal ALTERNATE configuration ?
Normal Off site power powers NAN-S03 which powers opposite bus PBB-S04; Normal offsite powers NAN-S04 which powers PBA-S03
What is Normal Shutdown Configuration?
-Off site power goes through either NAN-S03 or NAN-S04 & powers both trains
Where does PB system get its control power from?
Gets control power from PK system
What do some breakers on “B” train have on them ?
A remote & local disconnect switch with a square orange “R”,which allows you to disconnect the control room from the breaker in event of a fire in control room
What are seismic requirements for switchgear in service ? What’re the requirements when it’s out of service ?
Door handle latch with upper &lower Allen screw latches
When racking out breaker need to be raised 2in off ground or use proper restraints
How many under voltage relays are on each PB bus ?
Total of 9 undervoltage relays:
5for degraded voltage
-4 dedicated to detection & protection
-1dedicated to detection & control room annunciation
4 dedicated to under voltage detection and protection
What is degraded voltage ?
Drop in voltage on Class bus <90%of rated voltage for duration of 30seconds
What happens if voltage is recovered >90% before 30 seconds time limit is reached ?
The Undervolatge relays will automatically reset
How will the control room know an degraded voltage situation is occurring ?
A 5th undervoltage relay will actuate when <90% for 10 seconds has occurred, which sends alarm to control room
How many under voltage relays actuate on degraded voltage condition ?
A total of 5 relays will actuate:
-All 4 undervoltage relays will actuate (After 30 seconds)
-1 undervoltage relay actuating control room alarm (After 10seconds )
What is an undervoltage condition ?
Drop in voltage on class 4.16kv bus to <75% of rated voltage for any amount of time(instantly)
How many undervoltage relays actuate on an undervoltage condition ?
4 undervoltage relays actuate
What will automatically trip PB bus Normal/alternate Power Supply Breaker ?
-A load shed is generated from BOP-ESFAS system
-Alternate OR normal supply breaker is closed
-Fault on ESF transformer
-Relays that actuate an 86lockout
How does PB interface with NA
NA supplies normal power to PB class equipment
What CFR Appendix does the disconnect switch on bravo train come from ?
10CFR50 Appendix ‘R’
How does PB system interface with NB system ?
NBN-X03 &NBN-X04 ESF transformers supply 4.16KV to class bus PB
How do PB interface with PG?
Supply normal power to Class 480VAC Load Centers(PG)
How does PB interface with PH?
Class MCC Distribution panel supplies 120VAC to the PB switchgear space heaters to keep out moisture
How does PB interface with PK ?
PK supply’s PB switch gear with 125VDC control power
How does PB interface with DG ?
Diesel Generators(DG) supply power to PB bus during a Loss Of Offsite Power(LOOP)
How does PB interface with Essential Spray Ponds (SP)?
PB bus supply 4.16KV to SP pump motors
How does PB interface with Safety Injection(SI) ?
PB bus supplies 4.16KV power to safety injection pump motors
How does PB interface with Essential Chillers(EC)?
PB bus supplies power to EC system
How does PB system interface with Normal Chilled water (WC)?
PB bus supplies power to A normal chiller
How does PB system interface with Essential cooling water(EW) ?
Supplies power to EW pump motors
How does PB system interface with AF system ?
Supplies power to AF (N&B) pump motors
How does PB system interface with BOP- ESFAS ?
-provides under voltage & degraded voltage signals to BOP-ESFAS which initiated a LOP
-PB system receives load shedding and load sequencing BOP ESFAS signal during diesel startup to prevent overloading of generator
How does PB interface with HJ system ?
HJ supplies Normal & Essential Ventilation to ESF switchgear room
What will happen if Normal AHU (HJ) is lost ? What happens on a loss of any Essential AHUs?
-Then control room will start BOTH Essential AHUs to cool the rooms.
-If an Essential AHU or Essential chilled water is lost then that Trains class equipment is INOPERABLE
What is the loss of 4.16kv bus defined as ?
A Loss Of Power (LOP)
What needs to be started in 2.6 minutes to prevent the diesel generator from going into emergency stop ?
The associated Spray Pond Pump
What happens to the NK system if a blackout exceeds 1 hour ?
It limits the loads on NKN-M46 by, depressurizing generator & stopping Emerg. Seal oil & Bearing oil pumps
What happens if blackout exceeds 2 hours?
Than the SBOGS are to power 13.8kv system (NA) to recharge the Batteries(NK) to be able to operate switchyard breakers
What’re the Modes that need Electrical power subsystems ‘A’ train & ‘B’ train to be operable ?
Modes: 1, 2, 3, 4
