Main Condensers Flashcards
1
Q
Describe the design of the main condensers
A
- 3 vertical shells: 1 for each low pressure turbine
- Main condenser water boxes are split so you can isolate 1 half for maintenance
- unit 1 has equalizing ducts to avoid temp and pressure differences across bearings
- unit 2 each shell is separate
2
Q
What loads input in to the condensers
A
- Turbine section
- normal blowdown flashtank
- MFP ELOS
- makeup from cst
- drip receivers
- msr drain tank
- hotwell pump suction and discharge vents
3
Q
How does the hotwell level control system operate
A
- Level controller references leg a or c differential pressure
- 1 level controller controlls all hotwells
- crv 155 opens to let down water
- crv 55 opens to raise water level
- on loss of reference leg
- indicated level rises crv 155 opens actual level lowers, hotwell pump suction is challenged
4
Q
How will a high level in the condenser hotwell affect the operation of the plant
A
Lowers vacuum because the high level reduces surface area for the heat transfer on the tubes
5
Q
How will low hotwell level affect the operation of the plant
A
- reduces NPSH to the hotwell pump allowing it to cavitate and potentially steam bind
- if it causes low flow to the MFP suction the MFP will trip
- this will require a reactor trip in Unit 2