CP- Containment hydrogen purge Flashcards
In both of the containment purge subsystems, what happens when the exhaust rad monitors sense high radiation levels? The external rad monitors?
alarm
system isolates
What will stop a containment purge besides RU-37 and Ru-38 detecting radiation?
CIAS
How is the CP system affected by a loss of Non-Class 125 VDC?
Containment Refueling Purge AHU outlet dampers fail closed which will prevent operation of the AHU
Containment Power Access Purge AHU inlet damper fails closed which prevents operation of the AHU
What does the containment purge refueling purge subsystem AHU consist of?
filter, heating and cooling coils two fans
Concerning the Power Access Purge Normal Exhaust AFU, what is the purpose of the charcoal filter and second HEPA filter?
Charcoal filter removes fission product gases (mainly iodine) by adsorption
Second HEPA filter removes any carbon dust emitted from the charcoal filters
What is the flow path of the Containment Purge refueling purge subsystem?
outside air is drawn in through a single AHU with two fans. sends air through dampers and isolation valves to containment
two exhaust fans drawn air out of containment through dampers to the plant vent
some of the exhaust air flow goes through rad monitors with two external rad monitors as well
What does the containment purge power access purge exhaust AFU consist of? Where is it controlled from? Where is it located?
moderate, HEPA, charcoal, and HEPA filters and a fan
control room
aux. building roof
Where is the Power Access Purge Supply AHU controlled from? Where is it located?
Control Room
aux. building roof
What does the containment purge power access purge AHU consist of?
inlet damper, moderate and high efficiency filters, coils, fan and exhaust damper
Which radiation monitors continuously monitor Purge discharge flow to the plant vent?
RU-37 and RU-38
Where does the containment purge system purge the containment atmosphere to? Where does the filtered and treated make-up come from?
plant vent stack
outside air
What is the flow path of the containment purge power access purge subsystem?
outside air drawn in to a single AHU to containment
containment atmosphere is exhausted through isolation valves, heater and into exhaust AFU and then to the plant vent with rad monitors internal and external
How many containment purge refueling purge exhaust fans are normally running while the system is in operation?
two, keeping containment at a slight negative pressure
What happens if monitors RU-37 and RU-38 detect excessive radiation?
Initiate a CPIAS and stop the purge
The Power Access Purge has what two modes?
Venting or depressurization mode
Power Access Purge mode
What are the two subsystems of the CP system? Purposes?
Refueling Purge Subsystem – provides ventilation air for personnel comfort when the plant is shutdown during refueling operations and maintenance
Power Access Purge Subsystem – provides ventilation air to allow operator access for limited periods during power operation. Also used to control pressure in the containment by periodically venting a portion of the containment air to the plant vent
How is the system affected by a loss of IA?
Air operated dampers and valves fail closed, which will cause associated AHUs, AFU, supply or exhaust fans to trip
When does the WC system provide cooling to the Power Access Purge AHU?
When outside temperature is too high
Why is there a heater installed up stream of the Power Access Purge Normal Exhaust AFU?
To maintain humidity low to prevent damage to the charcoal filter down stream
What provides cooling in the Refuel Purge AHU and how is it controlled?
Normal Chilled Water
Automatically controlled to maintain inlet air temperature at a preset value
How is the CP system affected by a loss of Class 120 VAC?
Causes the CP system to shutdown and isolate from the containment
Power is lost to RU-37 (A Train) or RU-38 (B Train), which are used to generate CPIAS
Operating together as necessary for containment atmosphere clean-up is the Power access purge subsystem and what other system?
HC pre-access Normal AFUs
How does Instrument Air interact with the CP system?
Provides air for the operation of dampers, valves, controllers, and air operated containment isolation valves in the CP system
How does the Power Access Purge Supply AHU handle outside temperature being too low?
Electric heating coils are energized
When would I use Venting mode?
Utilized to depressurize the containment atmosphere during normal power operation or prior to power access purge
When is the Refueling Purge Supply AHU operated and where is it located?
Only in Mode 5 or 6
Located on the Aux Building roof
