Runbacks

Question 1

What are all of the Intermediate Runbacks?

Answer 1

1. Loss of 1 Reactor Feed Pump AND Reactor water level < level 4 (+30”)
2. Loss of 1 Circ Water Pump with 4 Circ Water Pumps running AND Condenser pressure > 4.5” HgA.
3. Loss of 1 Secondary Condensate Pump WITH total feedwater flow ≥ 73.65% AND 2 or more feed pumps in service.
4. Loss of 1 Primary Condensate Pump WITH total feedwater flow ≥ 73.65% AND 2 or more feed pumps in service.

Question 2

What are all of the Full Runbacks?

Answer 2

1. Reactor water level < Level 3 (+12.5”)
2. Total feedwater flow < 22% for > 15 seconds
3. Loss of 1 Circ Water Pump with 3 or less Circ Water Pumps running AND Condenser pressure > 5.8” HgA.
4. Loss of Stator Water Cooling for 27 sec(15+12)

Question 3

What is the purpose and setpoint of the Loss of 1 Reactor Feed Pump AND Reactor water level Runback and what is its associated setpoints?

Answer 3

Intermediate Runback
Reactor water level < level 4 (+30”)
Purpose: Reduction of power to maintain RPV water level.

Question 4

What is the purpose and setpoint of the Loss of 1 Circ Water Pump with 4 Circ Water Pumps running AND Condenser pressure Runback and what is its associated setpoints?

Answer 4

Intermediate Runback
Condenser pressure > 4.5” HgA.
Purpose: Reduction of power to limit condenser vacuum degradation.

Question 5

What is the purpose and setpoint of the Loss of 1 Secondary Condensate Pump WITH total feedwater flow XX % AND 2 or more feed pumps in service Runback and what is its associated setpoints?

Answer 5

Intermediate Runback
total feedwater flow ≥ 73.65%
Purpose: Reduction of power to maintain RPV water level.

Question 6

What is the purpose and setpoint of the Loss of 1 Primary Condensate Pump WITH total feedwater flow XX % AND 2 or more feed pumps in service Runback and what is its associated setpoints?

Answer 6

Intermediate Runback
total feedwater flow ≥ 73.65%
Purpose: Reduction of power to maintain RPV water level.

Question 7

What is the purpose and setpoint of the Reactor water level Runback and what is its associated setpoints?

Answer 7

Full Runback
Reactor water level < Level 3 (+12.5”)
Purpose: Maintains adequate Recirc and jet pump pump NPSH at low level conditions.

Question 8

What is the purpose and setpoint of the Total feedwater flow Runback and what is its associated setpoints?

Answer 8

Full Runback
Total feedwater flow < 22% for > 15 seconds
Purpose: Maintains adequate Recirc and jet pump pump NPSH at low feedwater flow conditions

Question 9

What is the purpose and setpoint of the Loss of 1 Circ Water Pump with 3 or less Circ Water Pumps running AND Condenser pressure Runback and what is its associated setpoints?

Answer 9

Full Runback
Condenser pressure > 5.8” HgA.
Purpose: Reduction of power to limit condenser vacuum degradation

(Bypassed when bypass switch is in “RECIRC RUNBK BYPAS” (Pictured at right))

Question 10

What is the purpose and setpoint of the Loss of Stator Water Cooling Runback and what is its associated setpoints?

Answer 10

Full Runback