PAH

Question 1

State the potentially contaminated areas of the PAB that PAH serves

Answer 1

Charging Pump Rooms
Demin Alley
VCT area
Sample Heat Exchanger Room
Fume hood
LTDN Hx and Filter Cells
Pipe Tunnel
Degasifier area

Question 2

State flow path for potentially contaminated areas

Answer 2

PAB Supply fans
potentially contaminated areas
return ducting 
PAH Cleanup Filter  (F-16) 
Filter Exhaust fans
Plant Vent Stack

Question 3

State PCCW air cooling alignment on LOP

Answer 3

Uses Safety Related A & B Train Fans and Dampers
PAH-FN-42-A / DP-43-A/DP-357
PAH-FN-42-B / DP-43-B/DP-358

Question 4

State flow path for Safety Related PCCW air cooling

Answer 4

• Outside air through Intake Louver to PAB Service Water Slot air Plenum
• A & B train PCCW Area Auxiliary Supply Dampers/Fans (DP-43-A/ B and FN-42-A / B)
• into PCCW Pump Area
• to Outlet Dampers (DP-357 / 358)
• back to Outside

Question 5

State how PCCW area cooling responds on high temperatures

Answer 5

If PCCW Pump area temperature reaches High I setpoint (105F):
- Lead train (A) inlet damper and outlet damper open
- Lead train (A) supply fan starts
If PCCW Pump area temperature reaches High II setpoint (110F):
- Lag train (B) inlet damper and outlet damper open
- Lag train (B) supply fan starts

Question 6

State how PAH/EAH respond on T-signal

Answer 6

PAH supply/exhaust dampers (35A/B and 36A/B) auto close
Fan 180 B starts due to low differential pressure
EAN-FN-180B or 180A provides CS pump room exhaust ventilation To maintain cooling for Charging Pump Motors
180B is preferred fan
180A is a backup and starts after 150 second time delay if 180B fails to start
No affect on previously running FN-5A/B or FN-31A/B
Emergency filter unit fans EAH-FN-4A & 4B start
FN-4A and 4B develop a negative pressure in all enclosure areas
FN-4A/B exhaust flow routed to Plant Vent Stack

Question 7

State how PAH Dampers respond on LOP

Answer 7

PAH dampers 35A/36A close on loss of power

Question 8

State how PAH (EAH) Fans responds on LOP

Answer 8

EAH-FN-5A/B previously running fan is restarted by Sequencer
FN-31A or 31-B The train associated exhaust fan aligned for Auto will restart after the previously FN-5A or B restarts (not started by sequencer)

Question 9

Describe how EAH-FN-180 respond to LOP

Answer 9

FN-180 B will auto start when the D/G breaker closes and the low d/p switch actuates
FN-180 A will auto start 150 seconds later if:
180 B fails to start (Low d/p ) &
Sequencer at step 9