1E Ac Power (Sro Cert)

Front 1

What is the purpose of the 1E AC power Distributon system?

Back 1

PURPOSE: Provides a reliable source of power for all class 1E loads. Class 1E loads are required for the following:
1 Safe and orderly reactor shutdown.
2 Maintaining the plant in a safe condition.
3 Mitigating the consequences of an accident.

Front 2

What are the 1E AC power Interlocks?

Back 2

1. Undervoltage

2. Overcurrent

3. Breaker Fault Protection

4. LOCA

5. Incomming Feeder Interlocks

6. Station Service Transformer Lockout

MNEMONIC: Uhazie Only Buys Lobster IF STeamed.

Front 3

EDG AUTO START SIGNALS?

Back 3

LOP/LOCA Sequencer initiating Signals:
1. LOP Bus undervoltage 70%. An ‘a’ contact (from EDG Bkr closure) activates timer.
2. LOCA is activated from Core Spray cktry on 1.68, -129 and/or CS manual.
(If there is a LOP concurrent with a LOCA, the LOCA sequencer (timer) will always be the controlling device.)

Front 4

10A-402 Bus loads?

Back 4

10A-402 Bus:
1. 1BX501 Normal Supply
2. B SACS pump.
3. B Core Spray pump.
4. B RHR pump.
5. B SSWS pump.
6. BK403 chiller.
7. 10B420.
8. 10B460.

Front 5

10A-401 Bus Loads?

Back 5

10A-401 Bus Loads
1. 1AX501 Normal supply
2. A SACS pump.
3. A Core Spray pump.
4. A RHR pump.
5. A SSWS pump.
6. AK403 Chiller.
7. 10B410.
8. 10B450.

Front 6

10A-403 Bus Loads?

Back 6

10A-403 Bus Loads
1. 1AX501 Normal Supply
2. C SACS pump.
3. C Core Spray pump.
4. C RHR pump.
5. C SSWS pump.
6. AK400 chiller.
7. 10B430.
8. 10B470.

Front 7

10A-404 Bus Loads?

Back 7

10A-404 Bus Loads:
1. 1BX501 Normal Supply
2. D SACS pump.
3. D Core Spray pump.
4. D RHR pump.
5. D SSWS pump.
6. BK400 chiller.
7. 10B440.
8. 10B480.

Front 8

What will cause the 10A-401 (402,403,404) infeed breakers to auto switch?

Back 8

<70% voltage (0.7 sec delay)

<92% voltage (20 seconds)

Will shift to other infeed if the alternate inffed is >94%.

Front 9

What will cause the EDG to Auto Start and load (LOP)

Back 9

Both infeeds are less than or equal to 92% for 20 seconds OR both infeeds less than or equl to 92% and bus voltage less than 70%.

Front 10

What vital buses are powered from the 1AX501 Station Service Xfmr in a normal system lineup?

Back 10

10A-401 and 10A-403. (#7 bus from 13.8KV ring bus powers the 1AX-501 which is stepped down to 4.16KV and powers the vital buses)

Front 11

What vital busses are powered from the 1BX501 Station Service Xfmr in a normal lineup?

Back 11

10A-402 and 10A-404. (#2 bus from 13.8KV ring bus powers the 1BX-501 which is stepped down to 4.16KV and powers the vital buses)

Front 12

Which EDG's power which vital buses?

Back 12

A EDG - 10A401

B EDG - 10A402

C EDG - 10A403

D EDG - 10A404

Front 13

What happens when an overcurrent condition exsists on a vital bus?

Back 13

The infeed breakers open and deenergize the bus. (LOCKOUT)

Front 14

The 10A401 normal infeed voltage dropped to 85% for 12 seconds and Bus voltage dropped to 65% for 1 second. Alternate inffed voltage is 96%...What will happen?

Back 14

The Alternate inffed will supply the bus since the normal supply dropped to below 70% for greater than 0.7 seconds. Since the Alternate source is above 94% the 10A-401 will be powered from the 1BX-501. (note: if the alternate inffed voltage was below 92% the A EDG would have auto started "LOP")

Front 15

The 10A404 bus is being powered from in its alternate source due to maintenance, what is the alternate source.

Back 15

Alternate supply is from the 1AX-501 station service transformer via the #7 bus on the 13.8KV ring.

Front 16

What is the design Basis for the 1E power dist. system.

Back 16

Three physically independent 500KV lines supply the switchyard with offsite power.

The 13.8KV ring bus is supplied from the 500KV switchyard through two sets of Station Power Transformers.

The switchyard and transmission network are designed to meet the requirements of 10CFR50, Appendix A, General Design Criteria 17. (Two physically independent circuits designed and located to minimize the likelihood of simultaneous failure).