CR HVAC

Question 1

What is included in the CR Envelope?

Answer 1

MCR, Kitchen, Locker Room, B Train HVAC Room

Question 2

What temp is required to be maintained for CR HVAC to be OPERABLE?

Answer 2

CR Temp <95F

Question 3

Under what conditions is HVAC designed to operate?

Answer 3

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

Question 4

What modes does the CR HVAC operate in?

Answer 4

Normal,
Isolation Pressurization
Isolation Recirc
Smoke Purge

Question 5

How does CR HVAC Isolation Pressurization Mode work and which trains support this?

Answer 5

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.

Question 6

How long does Operations have to isolate MCR and start AFU in DBA LOCA? What must be done and what signal requires this?

Answer 6

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

Question 7

How does the CREV Smoke Purge mode work? Which train provides this?

Answer 7

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

Question 8

How does Isolation/Recirc Mode work for CR HVAC?
Which train(s) support this?

Answer 8

Protects from onsite/offsite toxic chemicals or fires.
Must isolate ALL OUTSIDE AIR within 2 minutes
Either A or B

Question 9

How is Isolation/Recirc reset?

Answer 9

Manually from 105 panel in B vent room

Question 10

What is the normal CR HVAC total flow? Makeup?

Answer 10

Total flow 20000scfm; A train makesup up ~2000scfm.

Question 11

What is different about A&B CR HVAC Trains?

Answer 11

A has cooling and heating - B only has cooling

Question 12

What powers A HVAC AHU? Compressors? Cooling Water?

Answer 12

AHU - MCC 26-4
Compressors from Bus 25/26
Service Water Cooling

Question 13

What provides power to B HVAC (CREVS)?

Answer 13

MCC 29-8

Question 14

How does B CR HVAC Power source react on 4kV Undervoltage condition?

Answer 14

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

Question 15

What causes B CREVS Auto start?

Answer 15

A Train trip for any reason including manual trip

Question 16

What is normal cooling to B RCU? Backup? how is it swapped?

Answer 16

Normal cooling from Service Water
Backup from U2CCSW
Must be manually swapped

Question 17

What makes up the B CREVS Air Filtration Unit?

Answer 17

Prefilter - heater - pre-HEPA filter - charcoal adsorber - post-HEPA filter

Question 18

What happens if B CREVS reaches 350F?

Answer 18

System deluge lights off for charcoal adsorber fire

Question 19

How many booster fans are associated with the B CREVS system and when do they use?

Answer 19

2 - for use in pressurization mode

Question 20

What happens to CREVS on loss of IA?

Answer 20

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

Question 21

What provides cooling to CR AHVAC Hx?

Answer 21

Service Water on tube side

Question 22

How do the MCR HVAC A Train A&B Compressors function?

Answer 22

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

Question 23

What provides heating to MCR A HVAC?

Answer 23

Plant Heating Steam to hot water heat exchanger - tube side is hot water (hot water also to U2 Battery room heaters)

Question 24

Where are the MCR A HVAC Smoke detectors reset from?

Answer 24

2223-35 panel

Question 25

Under what mode operation(s) is the AFU functioning?

Answer 25

Isolation/Pressurization

Question 26

Under what Modes must CREVS be Operable?

Answer 26

1,2,&3

Movemetn of recently irradiated fuel assemblies

Question 27

If CREV inop, how long do you have to restore and are there any exceptions?

Answer 27

7 days to restore;

If INOP due to INOP CR Envelope, then initiate mitigating actions IMMEDIATELY, Restore w/in 90 day

Question 28

Under Smoke Purge Mode, which dampers change position?

Answer 28

53 opens
23 - opens
24 - closes