Class 4.16KV (PB)

Question 1

What is the meaning for “Class 1E” ?

Answer 1

Safety classification for electrical equipment that are needed for safe emergency reactor shutdown

Question 2

What is the meaning of “Train”?

Answer 2

Independent arrangement of equipment, devices and components available for safe shutdown

Question 3

Meaning of “Load Group”?

Answer 3

Arrangement of buses, transformers, switching equipment, and loads fed from common power supply

Question 4

What happens if you have degraded or loss of voltage on Class 4.16kv buses ?

Answer 4

Sends a Loss of Power( LOP) signal to Engineered Safety Features Actuation system

Question 5

What is considered a blackout ?

Answer 5

Loss of offsite power & loss of both emergency diesel generators

Question 6

Where does PBA-S03 & PBB-S04 receive its control power from ?

Answer 6

PBA-S03: PKA-D21
PBB-S04: PKA-D22

Question 7

Can 86 lockout be reset locally and remotely on PBA-S03 & PBB-S04?

Answer 7

Yes

Question 8

Why would you want to manually actuate an 86 lockout on a class 4.16kv breaker ?

Answer 8

To prevent breaker from closing due to load sequencing signal & allows control room to close it remotely whenever they’re ready

Question 9

What is the normal ALTERNATE configuration ?

Answer 9

Normal Off site power powers NAN-S03 which powers opposite bus PBB-S04; Normal offsite powers NAN-S04 which powers PBA-S03

Question 10

What is Normal Shutdown Configuration?

Answer 10

-Off site power goes through either NAN-S03 or NAN-S04 & powers both trains

Question 11

Where does PB system get its control power from?

Answer 11

Gets control power from PK system

Question 12

What do some breakers on “B” train have on them ?

Answer 12

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

Question 13

What are seismic requirements for switchgear in service ? What’re the requirements when it’s out of service ?

Answer 13

Door handle latch with upper &lower Allen screw latches

When racking out breaker need to be raised 2in off ground or use proper restraints

Question 14

How many under voltage relays are on each PB bus ?

Answer 14

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

Question 15

What is degraded voltage ?

Answer 15

Drop in voltage on Class bus <90%of rated voltage for duration of 30seconds

Question 16

What happens if voltage is recovered >90% before 30 seconds time limit is reached ?

Answer 16

The Undervolatge relays will automatically reset

Question 17

How will the control room know an degraded voltage situation is occurring ?

Answer 17

A 5th undervoltage relay will actuate when <90% for 10 seconds has occurred, which sends alarm to control room

Question 18

How many under voltage relays actuate on degraded voltage condition ?

Answer 18

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 )

Question 19

What is an undervoltage condition ?

Answer 19

Drop in voltage on class 4.16kv bus to <75% of rated voltage for any amount of time(instantly)

Question 20

How many undervoltage relays actuate on an undervoltage condition ?

Answer 20

4 undervoltage relays actuate

Question 21

What will automatically trip PB bus Normal/alternate Power Supply Breaker ?

Answer 21

-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

Question 22

How does PB interface with NA

Answer 22

NA supplies normal power to PB class equipment

Question 23

What CFR Appendix does the disconnect switch on bravo train come from ?

Answer 23

10CFR50 Appendix ‘R’

Question 24

How does PB system interface with NB system ?

Answer 24

NBN-X03 &NBN-X04 ESF transformers supply 4.16KV to class bus PB

Question 25

How do PB interface with PG?

Answer 25

Supply normal power to Class 480VAC Load Centers(PG)

Question 26

How does PB interface with PH?

Answer 26

Class MCC Distribution panel supplies 120VAC to the PB switchgear space heaters to keep out moisture

Question 27

How does PB interface with PK ?

Answer 27

PK supply’s PB switch gear with 125VDC control power

Question 28

How does PB interface with DG ?

Answer 28

Diesel Generators(DG) supply power to PB bus during a Loss Of Offsite Power(LOOP)

Question 29

How does PB interface with Essential Spray Ponds (SP)?

Answer 29

PB bus supply 4.16KV to SP pump motors

Question 30

How does PB interface with Safety Injection(SI) ?

Answer 30

PB bus supplies 4.16KV power to safety injection pump motors

Question 31

How does PB interface with Essential Chillers(EC)?

Answer 31

PB bus supplies power to EC system

Question 32

How does PB system interface with Normal Chilled water (WC)?

Answer 32

PB bus supplies power to A normal chiller

Question 33

How does PB system interface with Essential cooling water(EW) ?

Answer 33

Supplies power to EW pump motors

Question 34

How does PB system interface with AF system ?

Answer 34

Supplies power to AF (N&B) pump motors

Question 35

How does PB system interface with BOP- ESFAS ?

Answer 35

-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

Question 36

How does PB interface with HJ system ?

Answer 36

HJ supplies Normal & Essential Ventilation to ESF switchgear room

Question 37

What will happen if Normal AHU (HJ) is lost ? What happens on a loss of any Essential AHUs?

Answer 37

-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

Question 38

What is the loss of 4.16kv bus defined as ?

Answer 38

A Loss Of Power (LOP)

Question 39

What needs to be started in 2.6 minutes to prevent the diesel generator from going into emergency stop ?

Answer 39

The associated Spray Pond Pump

Question 40

What happens to the NK system if a blackout exceeds 1 hour ?

Answer 40

It limits the loads on NKN-M46 by, depressurizing generator & stopping Emerg. Seal oil & Bearing oil pumps

Question 41

What happens if blackout exceeds 2 hours?

Answer 41

Than the SBOGS are to power 13.8kv system (NA) to recharge the Batteries(NK) to be able to operate switchyard breakers

Question 42

What’re the Modes that need Electrical power subsystems ‘A’ train & ‘B’ train to be operable ?

Answer 42

Modes: 1, 2, 3, 4