Demineralized Water (DW) Flashcards
What is the purpose of the DW system?
Provides continuous and sufficient supply of demineralized and degasified water to several systems and services
DW supplies makeup water to which Surge tanks?
Diesel Generator Essential chilled water Essential Cooling water Turbine Cooling Water Nuclear Cooling water Normal chilled water
What other tanks does it provide makeup water to?
Auxiliary Boiler deaerator
RMWT
CST
Stator Cooling Coolant Tank
How can DW support CD during a startup?
Can supply water to the Condensate Service Header
Which system receives seal water from DS?
OW
Why is a nitrogen cover gas maintained in the DWST?
To ensure the water remains free of oxygen during storage
Where does the demineralized makeup water to the DWST come from?
WRF Surge-Rinse Tank
What would trip the Demineralized Water Transfer Pumps?
Low-low level switch provided on the tank
What is the status of the Demineralized Water Transfer Pumps under normal operations?
One pump is continuously operating to pressurize the demineralized water supply header
The second pump operated as required by demand as sensed by a low discharge header pressure
Where is the control switch for the Demineralized Water Transfer Pumps?
Control Room
What would automatically stop the Demineralized Water Transfer Pumps?
Low-low demineralizer water storage tank level or electrical overload
How could we get DW if the Transfer Pumps or the Demineralized Water Storage tanks are unavailable?
Can be supplied directly from the Water Reclamation Demineralized Water header
What is the normal DWST level?
It holds 125000 gal and maintained by level controller at 13’ 3” – 21’ 5”
Alarms at 5’ and 22’ and lo lo trips the pump at 4’ 2”
Where does the loop seal sump go?
When the seal sump is full, it goes to the yard area sump
