AOP-35 "Loss of Service Water"

Question 1

AOP-35 entry conditions

Answer 1

• EK-1124 “Traveling Screen HI DP” (9” H2O)
• EK-1129 “Service Water Pump Bay LO Level” (574’3”)
• EK-1163 “Critical SW Header B LO Pressure” (45 psig)
• EK-1164 “Critical SW Header A LO Pressure” (45 psig)
• EK-1165 “Non-Critical SW Header LO Pressure” (45 psig)

Question 2

AOP-35 automatic actions

Answer 2

• Standby SW Pump starts at 40 psig discharge pressure on an operating SW Pump
• Screen Wash Pump P-4 starts at 6” H2O differential level across the Traveling Screens

Question 3

AOP-35 reactor trip criteria

Answer 3

• SW Bay Level <= 572’
• Operator actions are not maintaining either Crit SW Header >= 42 psig
• Loss of Non-Critical SW as indicated by the following alarms:
  
  • -EK-1165 “Non Critical SW LO Pressure” (45 psig)

AND

 --EK-0259 "Exciter Cooler High Temp" (50 C)

 OR

 --PPC Urgent Alarm "Exc Field Cold Air RTD-31" (48 C)

 OR

 --PPC Urgent Alarm "Exc Diode Cold Air RTD-32" (48 C)

Question 4

AOP-35 immediate actions

Answer 4

NOTE: EXCITER DAMAGE MAY OCCUR WITHIN 10 SECONDS OF LOSING NON-CRITICAL SERVICE WATER

Verify EK-1165 “Non Critical SW LO Press” is clear

• If alarm is in and any of the following alarms are also in, then trip the reactor:
  
  • —-EK-0259 “Exciter Cooler HI Temp” (50 C)
  • —-PPC Urgent Alarm “Exc Field Cold Air RTD-31” (48 C)
  • —-PPC Urgent Alarm “Exc Diode Cold Air RTD-32” (48 C)
• If alarm is in and any of the following occur, then perform Attachment 1 to break condenser vacuum:
  
  • —-Non-Critical SW has been lost or isolated
  • —-Exciter Cold Air Temperature > 80 C or rising