AR- Condenser Air Removal Flashcards
What is the purpose of the AR system?
Establishes and helps maintain a vacuum on the shell side of the main condenser by removing air and non-condensable gases during plant startup and power operations
Reduces oxygen concentration in the condensate by deaeration to aid in water chemistry
What system cools the AR pump seal water coolers?
Plant cooling water
What system provides makeup seal water to the AR vacuum pumps?
Condensate Service Header
When would AR discharge valves realign and redirect flow through the post filter unit?
When Radiation Monitoring System detects high radiation in the AR discharge
Where are the AR pumps located?
100’ south side of the turbine building
The AR vacuum pumps are sized to lower condenser pressure to what value and in what amount of time?
5” HgA in ~1.5 hours
What powers the AR pumps?
NG
Which of the four AR pumps is the standby pump?
‘D’ Pump
What is “hogging” mode?
During plant startup operation, inlet gas is compressed in the first stage and discharged directly to the moisture separator, bypassing the second stage
A check valve in the first stage discharge line allows the vacuum pump to automatically shift to the “hogging” mode when the first stage discharge volume exceeds the capacity of the second stage
What is the purpose of the moisture separator in the AR pumps?
Separate vacuum pump discharge gas from the sealant accompanying it
Provide a surge volume and reservoir for the sealant
Where does seal water flow in the Seal Water Cooler?
Shell side
When is sealant sprayed in the inlet manifold?
During high vacuum operation to cool incoming gasses and condense any accompanying steam
Where is the post filter unit located?
140’ south side of the Turbine Building
The post filter unit consists of what components?
Moisture separators
Electric heating coil
Exhaust pre-filter (HEPA)
Activated Charcoal filter
Exhaust post-filter (HEPA)
How is the electric heating coil sized?
To reduce the exhaust gas relative humidity below 70% to maintain the charcoal filter’s absorption ability
What is required in order to enter the Post Filter Unit?
Radiation Exposure Permit
What does the NH system power?
AR pump motor space heaters
post filter blower
charcoal adsorption train heating coil
Where is the motor of the Post Filter Blower started from?
Either manually from the Control Room or automatically in response to a high radiation signal
What condenser setpoints would automatically start the ‘D’ Air removal pump?
“A” Condenser – 4.2” HgA
“B” Condenser – 4.8” HgA
“C” Condenser – 5.3” HgA
What systems must be in service prior to starting the AR system?
Plant Cooling Water, Instrument Air, Condensate Service Header, Gland Steam Seal and drain systems
What would happen up on a loss of AR?
During normal operation, would not have an immediate effect since the condensing steam will maintain vacuum
Non-condensable gases will build over time, causing a loss of vacuum that could require a turbine shutdown
Oxygen will increase in the condensate which could also require a power reduction
How long would it take before we see signs of a degraded vacuum after a loss of AR?
10-20 minutes
What three support systems are needed for AR system operation?
Plant Cooling Water, Instrument Air, and Condensate Service Header
How is the system affected by a loss of PW?
Overheating of any operating AR vacuum pumps due to buildup of excess heat
High vacuum pump seal water temperature would result in a loss of pumping capability as the seal water flashes to steam
