Low Voltage AC - RPS

Question 1

What are the three AC sources for the Low Voltage AC System?

Answer 1

RPS, Instrument Bus, ESS

Question 2

What is the Purpose of the Reactor Protection System?

Answer 2

Provide regulated, reliable power for the operation of the Reactor Protection System and related equipemtn to ensure reliable reactor shutdown

Question 3

What is the Design Critertia for the the RPS system?

Answer 3

Single failure of RPS will not prevent scram from occurring and spurious scrams will be avoided

Question 4

What is the normal power for the RPS Bus A?

Answer 4

MG Set B (Div II)

Question 5

What is the RPS Bus B normally powered from?

Answer 5

MG Set A (Div I)

Question 6

What normally powers RPS MG SET A?

Answer 6

MCC 28-2 (38-3)

Question 7

What normally powers RPS MG Set B?

Answer 7

MCC 29-2(39-2)

Question 8

What is the purpose of the RPS MG Set?

Answer 8

High inertia flywheel will maintain generator output within 5% of rated values for at least 1 second to keep RPS bus energized (WILL ACTUALLY SUPPLY FOR 2 SECONDS BEFORE TRIPPING ON LOW VOLTAGE)

Question 9

How may EPA’s are supplied per RPS Spower Supply?

Answer 9

2 installed in series

Question 10

What are the trips for an RPS EPA?

Answer 10

Overvoltage (129v)
Undervoltage (106v)
Underfrequency (56Hz)

Question 11

What is purpose of an RPS EPA?

Answer 11

They protect Class 1E components powered by RPS buses from abnormal voltage and frequency conditions resulting from failures of the non-Class 1E power supplies. Each EPA contains a breaker and associated monitoring module.

Question 12

What does EPA (RPS) stand for?

Answer 12

Electrical Protection Assembly

Question 13

What is the condition of the EPA Trip lights following a trip?

Answer 13

Cleared. THey do not seal in, therefore the light extinguishes as soon as the condition clears.

Question 14

What is the reserve power supply for the RPS bus?

Answer 14

Reserve Instrument and RPS Transformer powered by MCC 25-2

Question 15

What happens on an overcurrent of the RPS MG Set supply breaker?

Answer 15

results in loss of breaker indication at MG Set control switch on 902(3)-52 panel

Question 16

What protective features are installed on the RPS system to prevent power alignment issues?

Answer 16

Mechanical Interlock on RPS Buses to preent being fed from two sources at same time
Key Interlock to prevent MCC 25-2 from attempting to feed both “A” and “B” RPS Buses

Question 17

What is Lost on a loss of RPS Bus A?

Answer 17

Loss of RPS A Relays - causing half scram in RPS Channel A
CRD 117 scram pilot solenoid de-energize
PCIS Channel A Group 1, 2, & 3 sensor and trip relay loss of power (half group isolations)
Main Steam Line monitors A & C fail downscale
APRM Channels 1, 2, & 3 and LPRM group I INOP
RB Vent Rad Monitor “A” and Fuel Pool Rad Mon “A” lose power - starts SBGT and isloation of RB Vent

Question 18

What is lost on loss of RPS “B”?

Answer 18

Loss of “B” relays cause half scram on channel B
CRD 118 scram pilot valve solenoids de-energize
PCIS channel B group 2 and 3 sensor and trip relays loss power (half Grp 2 & 3 isol)
**APRM Channel 4, 5, & 6 and LPRM Grp II become INOP, APRM fail downscale and APRM apron lights illuminate
**RB Vent Rad Mon B and Fuel Pool Rad Mon B lose power, causes start of SBGT and Isolates RB Vent

Question 19

What is the TS requiremetn for RPS EPAs in service?

Answer 19

2 RPS System EPA for each in-service RPS MG-Set or Alternate Power are required to be operable (Modes 1, 2, & 5 with rod removed containing fuel)

Question 20

What is required with 1 RPS EPA INOP (in a single power supply)?

Answer 20

72 hours to remove power supply from service

Question 21

What is required if both EPAs in a power supply are iNOP?

Answer 21

1 hour to remove from service

Question 22

What will a trip of an MG Set Breaker do?

Answer 22

Cause MG Set to spin down and EPA’s to actuate