Aux Feed Water

Question 1

Purpose of the Aux feed Water system?

Answer 1

• Designed to mitigate core damage and RCS over pressurization during transient conditions.
• Provides a way for removing decay heat during plant cooldown through the RHR system

Question 2

3 AFW subsystems:

Answer 2

• 2 MDAFW pumps A/B (E1/E2)
• SDAFW Pump
• MDAFW pump C (powered by a diesel)
• All subsystems are designed to deliver 100% of the required feed flow to all 3 S/Gs

Question 3

4 credited ITS AFW flowpaths

Answer 3

• MDAFW A to B S/G
• MDAFW B to C S/G
• Etiher MDAFW to A S/G
• SDAFW to all 3 S/Gs

Question 4

AFW Water sources? where can it draw suction from?

Answer 4

-CST for All flow paths (primary)
-Service water system (AFW C cannot be lined up)
-Deep Well Pumps
-

Question 5

MDAFW pump power supplies?

Answer 5

• E1 A

- E2 B

Question 6

MDAFW Pump Flow Control Valves
FCV-1424 and 1425
Power supply? Normally? Fail? Location?

Answer 6

• Normally closed, throttle open on pump start
• Powered from IB2 and IB3
• Fail closed
• Located in MDAFW pump room

Question 7

V2-20 A and B
Cross Connect valves
Purpose? Power SUpplie?

Answer 7

• Establishes a flow path to the S/G A from either A or B MDAFW pumps
• A powered from MCC-9
• B powered from MCC-10

Question 8

SDAFW pump trips

Answer 8

• Manual (Red local trip button)
• Low Discharge pressure (650psig, closes steam inlet valves)
• Over-speed (10800rpm)

Question 9

V1-8 A/B/C
Steam inlet valves for SDADW pump
Powered from?

Answer 9

• A MCC-5
• B MCC-6
• C MCC-6

Question 10

SDAFW pump start signals aux oil pump power supply

Answer 10

• 2/3 LO-LO lvl on 2/3 S/Gs (16%)
• UV on 4KV busses 1&4 (15 sec time delay)
• AMSAC 2/3 S/Gs elow Lo-Lo setpoint 11% above 35% power
• Aux oil pump powered from MCC-6