Condenser Air Removal Flashcards
How fast can the Air Removal Pumps lower condenser pressure to 5HgA ?
In 1.5 hours
What condenser shell can the ‘D’ AR unit be aligned to ?
It’s a standby unit that can be aligned to any condenser shell
Where can you operate a Air Removal unit from?
Can be operated from control room
Where is each AR Pump powered from ?
Powered from a Non-class 480VAC MCC(NH)
What components does each AR unit consist of ?
-Vacuum pump
-Moisture separator
-Seal water Recirc. Pump
-Seal Water Cooler
What does the vacuum pump “hogging” operation do ?
First stage will compress & discharge to moisture separator bypassing the second stage
For the AR Vacuum Pump “hogging” operation,why is the second compression stage no needed ?
2nd stage isn’t required since there is small differential between condenser & atmospheric pressure
What is the check valve used for in the first stage discharge line do ?
Allows vacuum pump to auto shift to hogging mode when first stage discharge volume exceeds capacity of 2nd stage
When is AR Vacuum Pump hogging mode used?
Used during plant startup
How does normal “Holding” operation work for the AR Vacuum pump ?
-1st stage partially compresses gas &discharges to 2nd stage
-2nd stage compresses slightly above atmospheric pressure &discharges to moisture separator
What sealant do the rebuilt AR Pumps have ?
-Rebuilt has grease bearing instead of oil lubricated bearing
-Grease bearing should have no leakage
What does the AR Pump moisture separators do ?
Separates AR discharge gas from sealant & provides surge volume & reservoir for sealant
What is the gas flow path entering moisture separator ?
Gas rises through separator screens, exits through check valve at top of tank, & enters exhaust piping
Where does makeup water get added from when moisture separator level decreases ?
Makeup water from condensate service header will auto add water
What does the solenoid operated valves in the condensate seal water makeup lines do ? What happens when there is excess sealant ?
-Maintains seal water level in each supply line
-Overflow line from separator allows excess sealant to return to hotwell or be directed to floor drain
What removes heat from seal water ?
Uses plant cooling water to remove heat from seal water
Why is sealant sprayed into the inlet manifold during high vacuum operation ?
It cools incoming gases and condenses any steam
What does seal water recirculation pumps do?
Takes suction on separator tank & discharges to shell side of seal water cooler
What does the Charcoal Adsorption Train do ?
Removes moisture,particulate contamination, gaseous iodine, & methyl iodide from condenser exhaust gas
What does the Charcoal Adsorption Train filter unit consist of ?
-Moisture separator
-Electric Heating Coil
-Exhaust Pre-Filter
-Activated Charcoal Filter
-Exhaust Post-Filter
What does Charcoal Adsorption moisture separator do ?
Moisture separator removed moisture through mechanical filtration
What does the Charcoal Adsorption heating element do ? What’s heating element controlled by?
-Reduces exhaust gas humidity below 70% to prevent charcoal damage
-Auto controlled by signals from humidistat mounted in unit
What does the Charcoal Adsorption charcoal filter ?
Removes gaseous iodine
What alarms are on the charcoal filter ? What is used during fire for charcoal filter?
-HI temperature
-HI-HI Temperature
-Has water deluge system in case of fire
What is required before entering Post Filter Unit ?
Radiation Exposure Permit
What does the AR Post Filter Blower do ?
Assist AR Pump in maintaining flow when using Charcoal Adsorption Train
What will start the Post Filter Blower ?
-Can be started manually
-Can auto start when high rad signal from RU-141
Where is the AR Post Filter Blower powered from ?
Powered from 480VAC MCC (NH)
When will the ‘D’ Air Removal Pump start ?
Will auto start if Main Condenser pressure in any shells increases preset value
What pressure is each condenser shell normally operate at ?
‘A’ 4.2HgA
‘B’ 4.8HgA
‘C’ 5.4HgAv
What is the normal flow path for the AR discharge ?
Normally bypasses Charcoal Adsorption Train and goes through RU-141 to plant vent
What happens during normal operation if RU-141 exceeds radiation limit ?
Bypass valves will close,inlet & outlet of charcoal adsorption will open, & post filter blower will start
What will happen if Condenser Air Removal system is lost ?
-Vacuum decreases then turbine efficiency decreases
-If vacuum decreases enough than turbine will trip
-Oxygen could also increase in condensate which requires power reduction
