Inverters - .5

Question 1

What are the 1E 125 VDC buses?

Answer 1

10D410
10D420
10D430
10D440

Question 2

When one of the 1E 125 VDC buses are lost, what systems control power is lost?

Answer 2

bucket breaker control power for:
RHR
CS
SACS
SSWS
FRVS
SRV Pilot Valves
HPCI
RCIC

Question 3

When one of the 1E 125 VDC buses are lost, what systems logic is lost?

Answer 3

Logic for:
RHR
CS
SRV Pilot Valve LoLo set
ADS

Question 4

If you were to loose 125 VDC to the RHR pump breaker while it is operating, what will happen?

Answer 4

The pump will fail in the condition it is in (i.e., if pump is running then it will keep running)

Question 5

If the A or B 125 V DC bus is lost, how will it affect CS?

Answer 5

loss of control power to core spray F005A(B) – that loop will no longer work

Question 6

How does a loss of 125 V DC affect operations of an EDG?

Answer 6

EDGs look like they are running, but they are not
Loss of power to the air receiver starting solenoids

Question 7

How does a loss of 125 V DC affect operations of the 4160 V AC bus switchgears?

Answer 7

loses control power, locked into its current configuration and doesn’t respond to automatic or manual trips

Question 8

What occurs on a loss of a 481 Inverter?

Answer 8

INOP the LOP/LOCA sequencer for that channel
Loss of non-1E optical isolators(means you lose
indications like pump amps, flows, pressures, etc
on 1 E equipment
Loss of HPCI and RCIC in auto and manual
Diesel will start on a LOP and not a LOCA
Will bring in a lot of alarms

Question 9

What occurs on a loss of a 482 Inverter?

Answer 9

EDG will not start on LOP, LOCA, or any control room start
A(B) SLC will not start
Outer horseshoe buttons go blank, but the buttons still work, just no indication
Loss of this inverter brings in a single SACS alarm, otherwise silent. (on alarm panel A6 or A7, consistent with the inverter channel)

Question 10

What inverter source is removed when the Manual Bypass Switch is in Bypass to Preferred?

Answer 10

Backup 480 AC

Question 11

What inverter source is removed when the Manual Bypass Switch is in Isolate after preferred?

Answer 11

Backup 480 AC
Static switch is isolated

Question 12

What inverter source is removed when the Manual Bypass Switch is in Bypass to Backup?

Answer 12

Normal AC
Backup DC

Question 13

What inverter source is removed when the Manual Bypass Switch is in Isolate to Backup?

Answer 13

Normal AC
Backup DC
Static switch is isolated

Question 14

What type of supply is backup 480 V AC?

Answer 14

It is put through a transformer and voltage regulator, this is considered a REGULATED supply

Question 15

If normal power is restored following a loss of power and the manual bypass switch is in normal, what power source will be used by the inverter?

Answer 15

The static switch will automatically select the normal power source. Static switch is only useful if the selector switch is in ‘NORM’

Question 16

What is the result of a loss of the AD483 inverter?

Answer 16

loss of RPIS/RMCS (after a scram, without RPIS/RMCS, you are forced in to EOP101A- ATWS since you don’t know positively if the reactor is shutdown or not)

½ scram on loss of power to the APRM A/C channel voters

Question 17

What is the result of a loss of the BD483 inverter?

Answer 17

loss of OHAs and ‘B’ feedpump

½ scram on loss of power to the APRM B/D channel voters