Containment Purge System(VP) Flashcards
(39 cards)
What is the purpose of the Containment Purge System?
The purpose of the Containment Purge System is to reduce the airborne radioactivity levels in containment by purging the following atmosphere to the unit vent during refueling when periods of personnel access are required:
- Upper Containment
- Lower Containment
- Incore Instrument Room
What are the VP design requirements?
- Clean up containment through purge exhaust during refueling.
- Supply fresh air for contamination control when containment is/will be occupied.
- Supply fresh air for contamination control when the incore instrumentation room is/will be occupied.
- Exhaust containment air to the outdoors through the purge exhaust filter trains whenever the Purge Supply System is operated.
- Assure isolation of the system penetrations in the containment vessel.This is the only stated safety related function
What are the Containment Purge System subsystems?
- Containment Purge Supply
- Containment Purge Exhaust
- Incore Instrumentation Room(IIR) Purge Supply
- IIR Purge Exhaust
What is the purpose/design of the Containment Purge Supply Air Handling Units?
- Two 50% capacity air handling units along with a pre-filter and hot water heating coils
- Heating water is supplied by YH
- Air handling Unit isolation provided by a suction damper and a backdraft damper
What are the power supplies to the Containment Purge Supply Fans?
A - MXK
B - MXJ
What will automatically trip the Containment Purge Supply Fans?
- Containment Ventilation Isolation Signal
2. EMF-39(Containment side high radiation)
What is the interlock between the supply fans and the inlet dampers?
The inlet dampers open when the fans start and closed when the fans are stopped.
How do the supply and recirculation dampers(D5 and D6) just downstream of the supply fans work together?
They modulate by either providing more flow to the containment, or by recirculating more flow to control the pressure in containment. The adjustments are made manually using a rheostat.
How do we know when we need to make adjustments to the fan dampers?
RP monitors a piece of tape at the airlock to determine if pressure needs to be adjusted in containment
What is the interlock between the supply fans and the supply damper(D7)?
Supply damper(D7) opens when the supply fans start and closes when they are shutdown.
What will automatically close supply damper(D7)?
- Supply Fan securing
- Phase A(1.2psig containment pressure) isolation
- Loss of instrument air
What is unique about the EMF-39 signal to a running supply fan?
When the signal is reset the fans will restart, and valves will open, if they were running initially
What is the purpose of the Upper and Lower Containment Supply Dampers?
The upper and lower supply dampers split flow between the upper and lower containment.
What is the percentage of flow going to the Upper and Lower Containment when the mode selector switch is in NORMAL?
Upper - 65%
Lower - 35%
What is the percentage of flow going to the Upper and Lower Containment when the mode selector switch is in REFUELING?
Upper - 82%
Lower - 18%
What is the percentage of flow exhausted from the Upper and Lower Containment by the Purge Exhaust System?
Upper - 65%
Lower - 35%
What provides the hot water to the Containment Purge Supply plenums?
Building Heating(YH)
When will the Building Heating pumps associated with the Containment Purge Supply plenums automatically start?
- The first pump starts at less than or equal to 50F with a supply fan in service
- The second pump starts at less than or equal to 35F REGARDLESS of the supply fan status.
What is the design/purpose of the Containment Purge Exhaust Plenums?
- Two 50% capacity air handling units along with a prefilter, HEPA filter, carbon filter, and strip heaters
- The common inlet has a electric heater
- The exhaust plenum contains filters and a carbon bed for removing particulate and radioactive iodine
What is the power supply to the Containment Purge Exhaust Fans?
A - MXK
B - MXJ
Why are the flows to the Upper and Lower Containment changed with the mode selector switch in the REFUEL Mode?
The higher flow rate to the Upper Containment in the Refuel Mode ensures that radioactive contamination is pushed into Lower Containment.
What will cause a Containment Purge Exhaust Fan to automatically trip?
- Containment Ventilation Isolation Signal
2. EMF-39L High Radiation(Containment Side High Rad)
What is the interlock between the Containment Purge Exhaust Fan and the inlet damper(D1) to the Exhaust Plenum?
The damper opens when the fan starts and closes when the fan is stopped.
What will cause an automatic closure of the inlet damper(D1) the Containment Purge Exhaust Plenum?
- Containment Purge Exhaust fan is stopped
- Phase A(1.2psig Containment) isolation
- Loss of instrument air
