HA- Aux. building HVAC Flashcards
What areas are provided with recirculation air handling units the Aux Building?
CEDM cabinet room/MG set room
Charging Pump rooms
Areas below what level in the Aux Building are isolated from the normal HVAC system on a receipt of a SIAS?
100’
What system provides cooling to the HA Essential System ACUs?
Essential Chilled Water
How does HA and EW interact?
EW provides start/stop signals to HA ACUs when the EW pump is started/stopped
HA ACUs provide cooling and ventilation in the rooms in which EW system pumps are located
What system provides the motive force for various HA dampers?
Instrument Air
What components of the HA system are powered by NG?
Aux Building AHU Outside Air Heater, Access Control Area Normal AHU heating coil
During normal operations, what is the status of the HA Essential HVAC room coolers?
Standby
What maintains the lower levels of the Aux Building under a slight negative pressure after a SIAS?
Fuel Building/Aux Building Exhaust Essential AFUs
What is the capacity of the HA Outside Air Normal Supply AHUs?
50% each
Which Units have had its ‘A’ HA Outside Air Normal Supply AHU OIC replaced with filter media? Which AHUs still have the oil impingement cleaners?
Unit 1 and 2 ‘A’ units have filter media
all others have OIC
What is the purpose of the electric timer utilized in the OIC on the OSA Normal AHUs in the aux. building?
Controls a motor which intermittently rotates the filtering curtain through an oil bath
What situation would have us bypass the HA OSA normal AHU OIC timer and where can this switch be operated?
High dust loading conditions
operated from the control room
What provides cooling to the HA Outside Air Normal Supply AHUs?
Normal Chilled Water
What is the purpose of the HA Outside Air Normal Supply AHU interlock?
To ensure that the number of running AHUs are equal to or less than the number of running exhaust normal AFUs, which will maintain the Aux Building at a slightly negative pressure
What could be an adverse effect of air flow imbalances?
Fire dampers not being able to close in response to an actuation
Concerning the Access Control Area Ventilation system, what is meant by a dual duct AHU?
It takes suction from a single supply duct and distributes air to two distribution ducts
What provides the necessary heating for the hot duct in the Access Control Area Ventilation system?
Electric heating coil located in parallel with the cooling coil within the AHU
In regards to the Access Control Area Ventilation system, what provides the cooling water through the coil? What does the system provide conditioned air for?
Normal Chilled Water
RP island, labs, and RP locker rooms
What prevents Access Control Area Ventilation system normal heater operation when the AHU fan is not in operation?
A flow switch
What is the purpose of the mixing boxes in the Access Control Area Ventilation system? How many zones are associated with the system?
Controls air temperature by using pneumatic dampers to control air volume from the hot duct, cold duct air flow is not modulated and is full open
7 zones
How many Charging Pump Room Normal ACUs are there? What controls cooling flow through the unit?
Three ACUs (one per room)
auto flow regulating valve
When do the Charging Pump Room Normal ACUs start and stop?
On a receipt of a pump running signal
When the signal clears, a time delay actuates and maintains the ACU running for 5 minutes
What is the capacity of the CEDMCS Room Normal ACUs and what do they cool?
Two 100% capacity redundant ACUs
circulate air in the CEDM cabinet and MG Set rooms
How are the normal ACUs for the CEDM cabinet and MG set rooms operated? When are they normally in operation?
Manually operated by a local hand switches near the ACUs (120’ aux building)
Whenever the CEA drive mechanisms are energized
What is the purpose of the Fume Hood Normal Exhaust Fans?
Provide a positive means of exhausting air from areas where chemicals are used or potential radioactive gasses may be present
What are the various Fume Hood Normal Exhaust fans and where are they located?
2 Hot Lab
1 Cold lab
1 A. A. Spectrophotometer
1 Sample Room
All on the 140’ of the Aux Building
What is the capacity of the HA Normal Exhaust AFUs? What do they consist of?
Two 50% capacity units
30 high efficiency filters
2 banks of 30 HEPA filters
charcoal filter
30k cfm fan
What is the fan rated for in the HA Normal Exhaust Air Filtration unit? Where does it exhaust to?
30,000 cfm
plant vent
When are the D/P detectors that monitor HA AFU filters set to alarm on High D/P?
8.2” H2O
What happens if HA AFU filter D/P lowers to 1.5” H20?
Trips the opposite supply fan to ensure that the number of running supply fans do not exceed the number of running exhaust fans
Concerning the HA AFU filters, what could be caused by a perceptible drop in D/P?
Damage to or deterioration of filter media or gaskets
Concerning the HA AFUs, why is there a high temperature control assembly mounted downstream of the carbon adsorber?
Monitors the air temperature as it leaves the adsorber, alarming and illuminating a local yellow light when the airstream reaches 265F
At 310F a local red detection alarm is indicated
Should the thermistor cable be damaged, the device also provides a fault alarm and a local white light
What is the purpose of the water deluge system in the adsorber section of the HA AFU?
Connected to the Fire Protection system water supply of 100 psig in case of excessive adsorber temperature
Saturates the carbon in 3.5 minutes
What happens when water is applied to activated carbon filters?
Will cause all adsorbed materials to be released
When would I ever connect the water deluge system in the aux building HVAC system?
Excessive temperature levels to prevent reaching the ignition point of activated charcoal of 625F
What is the purpose of the HA normal exhaust AFU adsorber’s eight sample canisters?
They see the same air flow as the main beds, so we can test these canisters to determine the remaining adsorbency
When you start the Aux Building Normal Exhaust fan, what else occurs?
Also opens the Exhaust unit inlet damper and allows the associated suction damper to modulate open to control the negative pressure in the Aux Building
Why is the AFU fan’s suction damper limited to 60,000 cfm?
Prevent damage to the filters
What essential ACUs are part of the HA system?
HPSI Pump Room, LPSI Pump Room, CS Pump Room, EW Pump Room, AF Pump Rooms, and ESF Electrical Penetration Rooms
What happens with the ESF Electrical Penetration Room ACUs when a SIAS or LOP is generated?
ACUs will auto start and have to be manually secured at their MCC after the SIAS or LOP are secured
How long after the supply valves go closed will the Aux Feedwater Pump AHUs auto stop?
5 minutes
Where can the Aux Feedwater Pump AHU be started manually? How can the fans be stopped?
At the associated MCC breakers
If started manually, the fans will have to be stopped manually
All Auxiliary Building ACUs have a Temperature Switch High Alarm set at what value? Basis?
101F, it is an early warning of excessive room temperature rise
What is the maximum room temperature of all aux. building rooms?
120F
If a high temperature for AFP ‘A’ is due to a steam leak, what actions must be taken?
AFP ‘A’ room must be isolated from Room B within 1 hour to prevent degradation of both trains of aux feed due to high temperature
If any of the Essential ACUs lose an individual room cooler, it will make that rooms equipment inoperable. How long do I have to restore it?
72 hours
What does RU-8 monitor? (140’ East Pen)
The Exhaust duct for radiation before the air is treated in the normal exhaust AFUs
What does RU-9 monitor? (100’ East End)
Exhaust flow from the 100’ level and below, which helps us to detect leakage associated with various systems
What does RU-10 monitor? (120’ East End)
Monitors 120’ and above, which helps us to detect leakage associated with various auxiliary systems
How does HF interact with HA during a SIAS?
Upon a receipt of a SIAS, Essential HA system supply and exhaust dampers shut, isolating the Aux Building below the 100’ level, thus permitting exhaust into the fuel building via an interconnecting tunnel
Additionally, HF Essential AFUs fuel building inlet dampers close and the auxiliary building dampers open to align the fuel building essential AFUs to receive Aux Building Exhaust
How is HA affected by a loss of Instrument Air?
Normal AHUs discharge dampers fail close, causing the AHU fans to be dead-headed (Room temps will start to elevate due to no supply air)
Exhaust Normal AFU dampers on the suction side fail closed, causing the AFUs to run with a closed suction path that will cause the associated AHU to trip on low DP across the AFU
Access Control area AHU continues to run, taking suction on the HA supply header and may result in contamination of the 140’ spaces supplied by this AHU.
Hot air to the mixing boxes is stopped, causing the discharge to be in full cooling mode
WC flow to the charging pump room ACUs fails open
How is HA affected by a loss of Class 125 VDC?
HA system pump room supply and exhaust isolation dampers
-Isolation dampers that isolate below 100’ level of the Aux Building will fail closed
What is the purpose of the aux. building HVAC system?
ventilate and control the release of airborne radioactivity from the aux. building during normal plant operation
maintain the required thermal environment for the ESF equipment rooms during emergency situations
control the release of the airborne radioactivity caused by leakage from an area below the 100’ of the aux. building post LOCA
What does the HA system provide in the case a High Energy Line Break (HELB) occurs?
atmospheric vent path through the exhaust duct to the plant vent stack
When does the steam driven Aux feedwater pump AHU auto start? When will it stop?
when either of the two steam supply valves go open
5 minutes after both steam supply valves are closed
In the HA system, what is powered by NH?
non class fan motors, space heaters and fume exhaust fans
How is the HA system affected by a loss of the NK system?
HA normal AHU discharge dampers and normal AFU suction dampers are lost due to NK powering solenoids
How does the HA system interface with WC?
cooling water to the normal HA AHUs, access control ACU, CEDMCS room ACUs and charging pump room ACUs
