Instrument/Service Air Flashcards
Instrument Air Compressors power supplies
C-2A/C - LCC-11
C-2B - LCC-12
Header pressure maintained by Instrument Air Compressors
95-105 psi
Instrument Air Compressors controls
Hand - breaker closes, compressor cycles 95-105 psi
Off - breaker opens
Auto - breaker will close on low header pressure of 92 psi
Describe IAC sleep mode
Compressor runs unloaded for 10 minutes, it goes into sleep mode
Starts back up when header pressure drops below 95 psi
Breaker remains closed, so you still have red light indication in the CR
IAC auto trips
Overcurrent
Undervoltage
Loadshed - SIS (will not auto start, have to manually restart the compressor after EDG sequencing)
Microprocessor trip (doesn’t trip the breaker, so you will still have red light indication in the CR)
What cools the IAC’s
Air cooled by V-201A/B/C
IAC cooling fan controls
Auto - fan runs with compressor (NORMAL)
Manual - fan runs
Off - fan doesn’t run
IAC aftercooler cooling water supply
C-2A/C - Critical Service Water
C-2B - Non-Critical Service Water
Instrument air filter/dryer functions/specs
2 pre-filters, 2 post filters, 1 of each in service at a time
Max DP of 4 psi on the filters
2 air dryer towers, 1 in service at a time
Instrument Air to Containment CV-1211 function
Fails open
Has N2 backup to allow closure on loss of air
Service Air Header Isolation CV-1212 function
Isolates service air from instrument air
Fails closed
Auto closes on low header pressure of 85 psi
What is lost when service air is isolated
C/T level instrumentation bubblers VRS area fire protection valves Pumping trap for SIRWT HX ALPS Breathing air
Service Air/Instrument Air to FWP Cross Tie CV-1221 function
Fails open
Controlled from the CR
HP air compressor power supplies
C-6A - MCC-8 - D Bus
C-6B - MCC-7 - C Bus
C-6C - MCC-4 - E Bus
HP air compressor operating range
310-325 psi
HP air tank sizing specifications
At 260 psi, and the compressor not running, all valves can be stroked 2 times
What is safety related in the HP air system
A/B receiver tanks and piping from the tanks to the control valves
Limitation on cross-tying HP air
A/B can’t be cross-tied when safeguards equipment is required (Modes 1-3)
What is the pressure setpoint that service air automatically isolates?
85 psig
Where does service air isolation valve and alarm sense pressure?
Downstream of Instrument Air Dryer and filters
Where does Instrument Air Compressor auto start sense pressure?
Upstream of Instrument Air Dryer and filters
What are the Feedwater Purity Air Compressors power supplies?
Both are supplied from LCC 91
Which HP Air Receiver Tanks can be cross-tied?
T-9C can be cross-tied to either T-9A or T-9B
What is the pressure setpoint for Instrument Air Compressor standby start?
92 psig
