Auxiliary Feedwater & AFAS

Question 1

State the functions of the Auxiliary Feedwater System.

Answer 1

Provides sufficient feedwater for the removal of decay heat and Reactor Coolant Pump heat from the Reactor Coolant System during accident or normal operating conditions.

Question 2

Identify the normal Auxiliary Feedwater system flowpath.

Answer 2

Each Auxiliary Feedwater pump takes a suction from the associated unit Condensate Storage Tank.
The motor driven Auxiliary Feedwater pumps normally discharge to an associated Steam Generator through one [two] isolation valve(s).
Cross-connect valves allow each motor driven Auxiliary Feedwater pump to feed either Steam Generator.
The steam driven Auxiliary Feedwater Pump can feed either Steam Generator through one [two] isolation valve(s).
The Auxiliary Feedwater system ties into the Main Feedwater System downstream of the Main Feedwater Isolation Valves.

Question 3

State the purpose(s) of the Condensate Storage Tank

Answer 3

Supplies makeup water for the Condensate and Main Feedwater System during normal operation
Provides an emergency feedwater supply for the Auxiliary Feedwater pumps.

Question 4

State the purpose(s) of the Motor Driven Pumps

Answer 4

Either motor-driven Auxiliary Feedwater pump by itself supplies sufficient Auxiliary Feedwater flow to a Steam Generator to maintain an adequate heat sink for the Reactor Coolant System under the most limiting operational conditions.

Question 5

State the purpose(s) of the Steam Driven Auxiliary Feedwater Pumps

Answer 5

Supplies sufficient Auxiliary Feedwater flow to both Steam Generators to restore Steam Generator level and to avoid overpressurization of the Reactor Coolant System while supporting plant cooldown under the most limiting operational conditions.

Question 6

State the purpose(s) of the Steam Generator Isolation Valves

Answer 6

Provide isolation of Auxiliary Feedwater flow and level control of Steam Generators