Main Feedwater

Question 1

State the function of the Main Feedwater System.

Answer 1

Provides feedwater to the Steam Generators during normal, shutdown, and transient operations at the required pressure and temperature.

Question 2

State the purpose of the Main Feedwater Pumps

Answer 2

Supplies feedwater flow from the Condensate System to the Steam Generators at the required pressure and flow.

Question 3

State the purpose of the High Pressure Feedwater Heaters

Answer 3

Provides a stage of preheating for feedwater to raise cycle efficiency and reduce thermal shock to the Steam Generators.

Question 4

State the purpose of the Main Feedwater Regulating Valves

Answer 4

The Main Feedwater Regulating Valves (MFRVs) and Bypass Valves allow precise control of Steam Generator levels at various power levels.

Question 5

State the purpose of the Main Feedwater Isolation Valves

Answer 5

Provides isolation of a faulted Steam Generator during a Main Steam or Main Feedwater line break.

Question 6

Identify the normal Main Feedwater System flowpath.

Answer 6

The normal system flow path is:
From the Condensate System at the tube side outlet of Low Pressure Feedwater Heaters 4A & 4B to the Main Feedwater Pumps
The Heater Drain Pumps add preheated inventory and provide a pressure boost to the system just upstream of #4 heaters.
From the Main Feedwater Pumps through the tube side of 5A & 5B High Pressure Feedwater Heaters,
From the #5 heaters through the Main Feed Regulating Valves and Main Feedwater Isolation Valves to the Steam Generators.