Main condensate and make up control (CNM)

Question 1

What are the purposes of the Main Condensate System (CNM)?

Answer 1

1. Condenses steam exhausted from the low pressure main turbine, the feedwater pump turbines, and the turbine bypass (steam dump) valves
2. Maintains the net positive suction head (NPSH) required by the feedwater pumps
3. Also returns condensate and miscellaneous drains to the condenser hotwell
4. Preheats the condensate supplied to the main feedwater system
5. Supplies a source of cooling water for the steam jet air ejector and gland sealing steam exhaust condensers
6. Supplies de-superheating and exhaust hood sprays

Question 2

What is the purpose of the Condensate Makeup and Drawoff System (CNS)?

Answer 2

The condensate makeup and draw off system is designed to maintain condenser hot well level during steady state and transient operating conditions while providing non-safety class water storage for the auxiliary feedwater system and a source of makeup water to the auxiliary boilers

Question 3

What other components does the Condensate Makeup and Drawoff System provide makeup water tovia the demineralized water distribution system?

Answer 3

RPCCW
TPCCW
EDG fresh water expansion tanks
Condensate Chemical Feed System
Condensate Mixed bed demineralizers

Question 4

Where are the components for the main condensate system located?

Answer 4

Turbine building

Question 5

What components make up the main condensate system?

Answer 5

1. main condenser
2. three main condensate pumps
3. associated piping and valves

Question 6

What is the function of the main condenser?

Answer 6

condense and deaerate steam from the three low pressure main turbine exhausts, two main feedwater pump turbine exhausts, the turbine bypass control (steam dumps) valves, and from various equipment vents and drains

Question 7

What is the function of the main condensate pumps?

Answer 7

pump the condensate from the main condenser to the main feedwater system

Question 8

What is the condensate supplied from the main feedwater system also used for?

Answer 8

provide cooling water for the steam jet air ejector condensers, steam packing exhauster condenser, and extraction steam cooling within the low pressure feedwater heaters
Additionally, some of the water from the system is used to provide seal water for various pump and valve seals