CR HVAC Flashcards
What is included in the CR Envelope?
MCR, Kitchen, Locker Room, B Train HVAC Room
What temp is required to be maintained for CR HVAC to be OPERABLE?
CR Temp <95F
Under what conditions is HVAC designed to operate?
Normal conditions - maitnain CR between 70F and 80F w/ outside temp between -6F and 93F
Rad Protection under accidents
Toxic Gas Release Protection
Fire and Smoke Protection
What modes does the CR HVAC operate in?
Normal,
Isolation Pressurization
Isolation Recirc
Smoke Purge
How does CR HVAC Isolation Pressurization Mode work and which trains support this?
Prevents airborne contaminats to MCR A OR B Train can support Normal outside air isolates and AFU supplies makeup air (2000cfm) via booster fan MCR pressurized to >+1/8"WC Must be manually initiated.
How long does Operations have to isolate MCR and start AFU in DBA LOCA? What must be done and what signal requires this?
Have 40 minutes to isolate MCR and start AFU on RB Hi Hi Rad (4mR/hr) signal
Ensures 5REM TEDE is not violated
Designed to maintain MCR envelope for 30 days after DBA
Can only be set locally from B HVAC room
How does the CREV Smoke Purge mode work? Which train provides this?
This protects from fire and smoke in MCR - MANUAL INITIATION
A HCU provides 26000cfm during mode with EVERYTHING OPEN (53A&B OPEN, 24 CLOSED)
CREVS INOP in this MODE
How does Isolation/Recirc Mode work for CR HVAC? Which train(s) support this?
Protects from onsite/offsite toxic chemicals or fires.
Must isolate ALL OUTSIDE AIR within 2 minutes
Either A or B
How is Isolation/Recirc reset?
Manually from 105 panel in B vent room
What is the normal CR HVAC total flow? Makeup?
Total flow 20000scfm; A train makesup up ~2000scfm.
What is different about A&B CR HVAC Trains?
A has cooling and heating - B only has cooling
What powers A HVAC AHU? Compressors? Cooling Water?
AHU - MCC 26-4
Compressors from Bus 25/26
Service Water Cooling
What provides power to B HVAC (CREVS)?
MCC 29-8
How does B CR HVAC Power source react on 4kV Undervoltage condition?
MCC 29-8 is load shed - Reset UV in back of 902-8 or locally at bus in B HVAC room and close back onto bus
What causes B CREVS Auto start?
A Train trip for any reason including manual trip
What is normal cooling to B RCU? Backup? how is it swapped?
Normal cooling from Service Water
Backup from U2CCSW
Must be manually swapped
What makes up the B CREVS Air Filtration Unit?
Prefilter - heater - pre-HEPA filter - charcoal adsorber - post-HEPA filter
What happens if B CREVS reaches 350F?
System deluge lights off for charcoal adsorber fire
How many booster fans are associated with the B CREVS system and when do they use?
2 - for use in pressurization mode
What happens to CREVS on loss of IA?
SW Valves fail closed and CCSW valves fail open
B Train auto starts and runs on recirc mode
ALL dampers except for 58/59 fail closed
AFU booster fan discharge dampers must be manually opened if pressurization mode required
What provides cooling to CR AHVAC Hx?
Service Water on tube side
How do the MCR HVAC A Train A&B Compressors function?
One is in lead, one is in lag - lead reacts to temperature and lag reacts to whether or not lead can keep up with temp
What provides heating to MCR A HVAC?
Plant Heating Steam to hot water heat exchanger - tube side is hot water (hot water also to U2 Battery room heaters)
Where are the MCR A HVAC Smoke detectors reset from?
2223-35 panel
