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
