Shield Cooling Flashcards
What is the purpose of the Shield Cooling System
Designed to maintained structural concrete temperature less than 165 F, preventing weakening of the concrete due to moisture loss
When is the Shield Cooling System required to be in service?
When PCS temperature > 165 F
What is required if concrete temperature can’t be maintained below 165 F?
Commence a controlled plant shutdown
What are the power supplies for P-77A/B, Shield Cooling Pumps
P-77A - MCC-2
P-77B - MCC-1
What are the control room controls for the shield cooling pumps?
- 3 position handswitch CLOSE/TRIP/PULL TO STANDBY
- CLOSE - starts pump
- TRIP - stops pump
- PULL TO STANDBY - places pump in standby. pump will auto start on low pressure of 35 psig
What is the low discharge pressure alarm setpoint for the shield cooling pumps?
35 psig
How many shield cooling coil sets are there?
2 (A and B)
How many coils are in each shield cooling coil set?
1 floor slab coil and 3 wall coils
What are the shield cooling temperature and flow alarms?
120 F
80 gpm
CV-0932/0934, Coil Inlet Supply Valves, design features
- Fail open
- OPEN/CLOSE keyswitch in Control Room
- Interlocked so when the valve is closed, its coil set low flow alarm is bypassed
Shield Cooling Surge Tank design features
- Sized such that the tank will not overflow from a temperature rise from 60 F to 212 F
- Makeup water is from T-81
CV-0939, Shield Cooling Containment Isolation Valve
- Closes on CHP/CHR
- Normally closed to isolate makeup water from the tank, because CV-0927, Surge Tank Makeup Valve, leaks by
How are chemicals added to the Shield Cooling System?
Chem add tank on east mezzanine is no longer used. Sodium Nitrite is added directly to the tank