Fuel Pool Ventilation System(VF) Flashcards
What is the purpose of the Fuel Pool Ventilation System?
- Control fission product emissions following a fuel handling accident(the only safety related function)
- Maintain a suitable environment for the operation, maintenance, and testing of equipment
- Maintain a suitable access and working environment for personnel.
What is the system designator for the Fuel Pool Ventilation System?
VF
What is the capacity of a Fuel Pool Ventilation Supply Fan?
A Supply Fan is 100% capacity, with a flow rate of 26,260cfm.
What areas receive air from the Fuel Pool Ventilation Supply Fan?
- Fuel Pool Area
- New Fuel Storage Area
- Fuel Unloading Area(RR Bay)
- ‘B’ Train VF Filter Unit Room
- Hot Instrument Storage Area(I&E)
- Upper Containment/Reactor Building Access Area
How many Supply Fans are there for each unit?
1 Supply Fan for each unit
What components makeup the Supply Air Handling Unit?
The Supply AHU consists of:
- Outside Air Damper
- Inlet Filter
- Finned Tube Heating Coil
- Finned Tube Cooling Coil
- Belt Driven Centrifugal Supply Fan
What is the design characteristics of the Supply Damper?
- The Supply Damper Fails Closed.
- The Supply Damper opens when one of the two Exhaust Filter Trains start.
- The Supply Damper is a Tornado Isolation Damper.
What systems provide heating and cooling for the Supply Air Handling Unit?
- Heating is supplied by Plant Heating(YH)
2. Cooling is supplied by Containment Chilled Water(YV)
How many Exhaust Trains/Fans are there for each unit?
- There are two Exhaust Trains for each unit.
- Each train consists of:
A. Two 50% Exhaust Fans
B. Two Exhaust Filter Assemblies, one for each Exhaust Fan
What is the normal flow path through the Fuel Pool Ventilation Exhaust path?
The normal flow path has 2 Exhaust Fans in operation with their Filter Assemblies bypassed.
How many air changes over the Fuel Pool do the Exhaust Fans achieve in one hour?
10 air changes per hour to:
- Ensures radioactive material released from the pool is captured.
- Reduces the relative humidity of the air for personnel comfort.
What components make up the Exhaust Filter Assembly?
- Prefilters
- Electric Heater
- Absolute Filter(Carbon Bed)
What type of damper is the Exhaust Train Inlet Damper and how does it fail?
The Exhaust Train Inlet Damper is electro-hydraulically operated and fails in the open position.
What type of dampers are used for the Exhaust Filter Assembly Inlet, Outlet, and Bypass? How do they fail?
- The dampers used for the inlet, outlet, and bypass around the Exhaust Filter Assembly are pneumatically operated.
- The dampers fail:
A. Inlet - Open
B. Outlet - Open
C. Bypass - Closed
What is the normal flow path through the Exhaust Train as it pertains to the Exhaust Filter Assemblies?
The Filter Assemblies are normally bypassed.
What will cause the Exhaust Filter Assemblies to be automatically/manually placed in service?
Automatically:
- EMF-42 High Rad Trip 2
- EMF-35, and EMF-36 High Rad Trip 2
- VC-YC switch to “Local” position
Manually:
- When EMF-42 is INOPERABLE to comply with SLC
- For testing as required
Where are the controls for the VF system located?
The VF system is controlled from MC-5R in the Control Room.
What is the purpose of the Mini-Flow Recirc Cross Connect Valves?
They are used to cool a filter bed that has a high temperature due to the decay heat produced from radio-iodine collected in the charcoal bed following an accident.
What is the affect on the Mini-Flow Recirc Cross Connect Valves with their control switch in AUTO?
With the switch in AUTO at MC-5R, the valve that allows air flow through the filters, will automatically shut for the associated train when that train is started.
What is the position of the Filter Assembly Isolation Dampers based on the VF Filter Mode Select Switch position?
- Open in the Filter Mode
- Closed in the Bypass Mode
- Fail Open
What is the position of the Filter Assembly Bypass Damper based on the VF Filter Mode Select Switch position?
- Open in the Bypass Mode
- Closed in the Filter Mode
- Fails Closed
What is special about the Filter Assembly Outlet and Bypass Dampers?
The Filter Assembly Outlet and Bypass Dampers are also Tornado Barriers.
What are the differences between the Unit 1 and 2 Fuel Pool Ventilation Systems?
- Unit 1 Containment Chiller water must be manually throttled to maintain supply air temperature greater than or equal to 70F.
- Unit 2 only has a thermostat that controls heating and cooling water supplies to maintain the outlet of the Supply Unit temperature at 60F.
What is the normal position of the VF Filter Mode Select Switch for the operating and the standby train?
- Operating train - Bypass
2. Standby Train - Filter
How are the VF Filter Trains interlocked?
There is an interlock that allows only one filter train to run at a time.
What affect does a LOCA have on the VF Filter Trains?
The Filter Trains trip on LOCA sequencer actuation.
What affect does a Blackout have on the VF Filter Trains?
The Filter Trains start if a Blackout occurs.
What affect do smoke alarms have on the VF System?
- The Exhaust Fans continue to run
2. The Exhaust Fans can be shutdown manually from the Control Room.
What affect does placing Control Room Ventilation(VC)/Control Area Chilled Water(YC) in LOCAL have on the VF system?
- All Control Room controls and interlocks are bypassed.
2. VF Filters receive a signal to align to the Filter mode.
What is the interlock associated with Supply Fan low inlet temperature?
40F - freeze protection is sensed at the outlet of the heating/cooling coil and will trip the Supply Fan.
What is the interlock associated with Supply Fan high inlet temperature?
160F - filter train inlet greater than setpoint will trip the Supply Fan.
What is the Fuel Pool Ventilation System interface with Plant Heating(YH)?
Plant Heating provides the hot water to the heating coils to control incoming air temperature.
What is the Fuel Pool Ventilation System interface with Containment Chilled Water(YV)?
Containment Chilled Water provides the cold water for the cooling coils to control incoming air temperature.
What is the Fuel Pool Ventilation System interface with Fire Protection(RF)?
Fire Protection provides water for the Exhaust Filter deluge in case of fire.
What is the Fuel Pool Ventilation System interface with Radiation Monitoring(EMF)?
Radiation Monitoring(EMF-35, EMF-36, and EMF-42) provides a signal when high radiation is detected to the Fuel Pool Ventilation Exhaust system to go to the filter mode.
Why do we normally bypass the Exhaust Filter?
To extend the life of the filters and carbon bed
Why is the standby Exhaust filter normally in Filter Mode?
To extend the life of the Filter Damper Actuator
What affect does a LOCA have on the VF Exhaust Fans?
- The Exhaust Fans are automatically stopped by the LOCA Sequencer. The sequencer must be reset to allow manually starting the Exhaust Fans.
What is the affect on the Exhaust Fans during a loss of electrical power?
- Exhaust Fans are automatically restarted by a Blackout sequencer.
Following a loss of electrical power which Exhaust Train will start?
The Exhaust train which receives the start signal first will start regardless of which train was previously running. Only one train will start due to the interlock.
What part of the system design ensures that the Exhaust Filter Outlet Damper has the ability to close for tornado isolation?
There are air tanks to provide air pressure for closing the Exhaust Filter Outlet Damper if instrument air is lost.
When is the Fuel Pool Ventilation Exhaust System required to be in service?
During the movement of recently irradiated fuel assemblies in the Fuel Building
What is the power supply for the for the Exhaust Fans, Cooling Bypass (Miniflow) Valves, and Filter Train Heaters?
Essential 600V MCCs
What is the power supply for the Supply Fans?
Non-essential 600V MCCs
