Air Removal System Flashcards
What does the air removal system do?
establishes and maintains a vacuum on the main condenser
Where do the AR pumps take a suction from?
the air off take pipes that run inside the condenser between the tube bundles
Why do the AR pumps normally exhaust around the post filter unit to the plant vent?
because during hogging (drawing the initial vacuum) the flow can be very high and could damage the filter unit. There should be no radiation present during initial vacuum draw, so the monitor and filter are not needed
Where does makeup to the AR pump seal water come from?
the Condensate service header
How many AR pumps are there and how many are normally operated?
- 3 are normally running and the 4th will auto start at a pre set setpoint. It varies in each condenser shell.
What do the seal water recirc pump do?
take a suction on the separator tank and discharge to the shell side of the seal water cooler to circulate and cool the seal water.
What components make up the post filter unit in the AR system?
Moisture separators Electric heating coils HEPA pre filter activated charcoal filter HEPA post filter
What does the charcoal filter section do?
remove gaseous iodine in the air stream
What powers the post filter blower?
NHN
What happens to the main condenser on a loss of AR?
no immediate effect since the steam condensing maintains the vacuum, but over time air and non condensable gases will build up and cause lowering vacuum (10-20 minutes). O2 will also build up in the condensate which could require a power reduction.
What happens to the AR system on a loss of IA?
pump suction valves fail closed
post filter unit inlet valve fails open
post filter unit bypass valve fails closed
