BCW Fill & Purge

BCW Fill & Purge

ISOLATION OF CC PUMP

• Remove from Stand by mode if it is in auto
• 1.2 Stop CC pump if running
• Isolate it Electrically
• Close both discharge valve of CC pump if boiler is to be drained.

If Work is to be carried out in Motor Cooling Water Circuit

• Isolate the inlet & outlet manual valve of LP cooler
• Ensure the water flowmeter reading of LP coolercooler shows zero value.

If Work is to be carried out in Pump or in High Pressure line

• Ensure the Unit is under Shutdown
• Ensure that the Suction Manifold temp. is less than 100 deg C.
• Close both discharge valve of all CC pumps.
• Drain the Boiler
• Open the pump casing vent of all CC pumps.
• After water stops coming from all pump casing vent, then open the pump casing drain.
• Ensure that the cavity is completely drained.

CC PUMP FILL PURGE

• Ensure the following :

1. Electrical Isolation of CC pump
2. Both Discharge valve closed
3. Boiler is in drained condition.

• Ensure both manual valves (just before entering pump cavity ) for filling pump cavity are in close condition so that water does not enter pump cavity.
• Ensure DM Make up pump is running.
• Open the basket strainer drain
• Ensure the supply valve from BFP discharge is close and open the supply valve from DM make up pump to basket strainer.
• Flushing is to be carried out from basket strainer drain until clean water starts coming out.
• Open the fine filter drain valve& close the basket strainer drain valve
• Line Flushing to be carried out from fine filter drain valve until clean water starts coming out
• Open the final drain valve just before entering BCW pump cavity& close the fine filter drain valve.
• Line Flushing is to be carried out from drain valve just before entering pump cavity until clean water starts coming out & conductivity is less than 1 μs/cm.
• Inform Chemistry to keep measuring conductivity of water on hourly basis until three consecutive readings of conductivity less than 1 μs/cm is achieved.
• Adjust the flow rate of water coming out of drain to 5 LPM after chemistry clearance. (After three consecutive reading , conductivity less than 1 μs/cm )
• Open the casing vent of all pumps & both the manual valves for cavity filling. Close the drain valve.
• When water starts coming out from pump casing vent, measure the conductivity of water.
• On Achieving three consecutive readings of conductivity less than 1 μs/cm, pump casing vent & cavity filling line manual valves are to be closed.
• Close main supply valve from DM make up pump (For Purge & filling)
• Inform EMD for Motor Meggering.Take Electrical Clearance before starting pump.
• Open Both discharge valves of CC pump after drum filling.
• Normalize cooling water isolation valves & note down the cooling water flow rate of LP & cooler.
• BCW pump can be started & observe its cavity temperature