HC- Containment HVAC Flashcards
Describe the RU-1 containment penetration isolation valves. What system powers them? When will they fail closed?
Two installed on each penetration, one inside containment and the other outside
Each valve is class powered and will fail close upon a loss of power (PK), will close on CIAS
Suction line – UV-47 (B train) and UV-46 (A train)
Return line – UV-44 (B train) and UV-45 (A train)
What happens when the Containment CEDM Normal ACU control switch is turned to the start position?
ACU fans start, intake damper and NC system cooling water supply valve both open
What is the auto feature associated with the Containment Reactor Cavity Cooling Fans?
Provided between ‘A’ and ‘B’ and the ‘C’ and ‘D’ fans
Ex. If ‘A’ fan is in AUTO and a low D/P is sensed across the ‘B’ fan, ‘A’ fan will auto start after 60 seconds
How many AFUs are used in the MSSS Ventilation Supply? What is inside the AFUs?
two, One for each fan
dry filter media with a high D/P alarm and an abandoned oil impingement cleaner
What is the purpose of the Containment CEDM Normal ACUs and what do they consist of?
Keep CEDM temperatures within limitations
Consists of two CEDM Normal ACUs, each equipped with two fans for a total of four fans and set of cooling coils, ducting and dampers (on 157’ containment)
Concerning the Containment CEDM Normal ACU, what happens if a pair of operating fans tripped?
Low D/P across the fans are sensed, which will automatically start the other pair of fans after a 120 second time delay as long as its control switch is in the “Normal After Stop” position
How many Containment Pressurizer Space Exhaust fans are normally running?
One, while the other is in AUTO
What is the purpose of the HC system?
Maintain temperatures and airborne activity in the containment within acceptable limits for equipment operation and personnel access
Supplies outside air to and exhausts from the MSSS in order to cool the main steam and feedwater piping penetrations
When are the Containment Pre-Access AFUs operated and where are they located?
As necessary to support personnel access to the containment building during power operation and prior to opening containment for an outage
Located on the 140’ of Containment
What is the purpose of the Containment Tendon Gallery Supply and Exhaust Fans and where are they located?
Supply and exhaust fans that operate to ventilate the tendon gallery area to ensure a habitable environment prior to personnel access
Located on 100’ level outside containment building
Concerning the Containment CEDM Normal ACU fans, why are there backdraft dampers installed on the discharge side?
To prevent a short circuit air flow condition during single fan operation
Under normal conditions, how many Containment CEDM Normal ACUs are operating? Can a single fan cool the CEDMs properly?
Only one, with both of its fans running
yes
How does the HC system interface with the PPS?
pressure transmitters inside containment generate actuations based on containment pressure
What cooling water flows through the Containment CEDM Normal ACU cooling coils and what starts it?
Nuclear Cooling Water
started automatically when an associated fan is started
Isolated when fan is stopped
While doing rounds, you notice that the MSSS Ventilation Supply fan motor is operating, but the blades are not spinning. What happened?
Fans are belt driven; the belt has broken or come loose
What is the auto feature associated with the Containment Pressurizer Space Exhaust Fans?
If ‘A’ fan is in AUTO and a low D/P is sensed across the ‘B’ fan, the ‘A’ fan will auto start after 60 seconds
Same would occur if ‘B’ was in AUTO and ‘A’ was running
What is the purpose of the Containment Normal ACU fan 60 second time delay?
Allows the non-operating fans to come to a stop if the back draft or suction damper were leaking, which would cause the fans to spin backwards
Explain the operation of the RU-1
Located in the Aux building, it draws a suction sample from the 95’ level of containment for monitoring
After monitoring is complete, the sample is returned to containment
The four Containment Normal ACU fans are powered from what system? Where are they located?
PG (PGA-> ‘A’ ‘C’, PGB-> ‘B’ ’D’)
120’ containment
What happens to the Containment CEDM Normal ACU upon a receipt of a SIAS?
Stops all operating fans, which can be restarted after they are placed in override