Aux Feedwater Flashcards
LCO 3.3.3 “Engineered Safety Features (ESF) Instrumentation” requirement
4 ESF bistables and associated instrument channels for AFAS signal, A S/G low level, and B S/G low level shall be operable
LCO 3.3.3 “Engineered Safety Features (ESF) Instrumentation” applicability
Modes 1-3
LCO 3.3.4 “Engineered Safety Features (ESF) Logic and Manual initiation” requirement
2 ESF manual initiation and 2 ESF Actuation logic channels and associated bypass removal channels shall be operable for each AFAS channel
LCO 3.3.4 “Engineered Safety Features (ESF) Logic and Manual initiation” applicability
Modes 1-3
LCO 3.3.7 “Post Accident Monitoring (PAM) Instrumentation” requirement
The PAM instrumentation for each Condensate Storage Tank level, A S/G wide range level, and B S/G wide range level shall be operable
LCO 3.3.7 “Post Accident Monitoring (PAM) Instrumentation” applicability
Modes 1-3
LCO 3.3.8 “Alternate Shutdown System” requirement
The Alternate Shutdown System Functions Aux Feed Flow Indication to S/G A, Aux Feed Flow Indication to S/G B, AFW LSP alarm (P-8B), P-8B steam supply valve control, AFW flow control to S/G A, and AFW flow control to S/G B shall be operable
LCO 3.3.8 “Alternate Shutdown System” applicability
Modes 1-3
LCO 3.7.5 “Auxiliary Feedwater (AFW) System” requirement
2 AFW trains shall be operable
- Only 1 train, which requires a motor driven AFW pump is required in Mode 4
- P-8B is only required prior to making the reactor critical
- 2 AFW pumps may be placed in manual for testing for a period of up to 4 hours
LCO 3.7.5 “Auxiliary Feedwater (AFW) System” applicability
Modes 1-3
Mode 4 when S/G is relied upon for heat removal
LCO 3.7.5 “Auxiliary Feedwater (AFW) System” required actions if less than 100% of the required AFW flow is available to both S/Gs
IMMEDIATELY
Initiate action to restore 1 AFW train to operable
What is the minimum required combined inventory in T-2 and T-81, including individual tank percent levels?
- required combined inventory of 100,000 gallons for decay heat removal for 8 hours
- T-2 - 71%
- T-81 - 83%
What is the normal water supply to the AFW pumps?
T-2
What is the alternate water supply to the AFW pumps?
P-8A/B - Fire Water
P-8C - Service Water
What are the AFW pumps power supplies?
P-8A - Bus 1C
P-8C - Bus 1D
What are the LSPT setpoints for the AFW pumps?
P-8A/B - 6.7 psig (2/3 logic)
P-8C -8 psig (2/3 logic)
What is the design flow capacity of the AFW pumps?
P-8A/B - 415 gpm
P-8C - 330 gpm
What is the precaution associated with operating P-8C with only flow through its miniflow?
- Pump total flow should be > 75 gpm
- Miniflow is only 30 gpm
- Pump should only be operated like this for < 2 minutes, and shall be < 5 minutes
What is the order of pump starts on AFAS?
P-8A
P-8C
P-8B
Where does P-8B steam supply come from?
S/G A
Supply from S/G B broke underground, so it is isolated
How is P-8B operated from C-150/C-150A?
2 switches to transfer control from the Control Room to C-150/150A, and P-8B steam supply CV-0522B control
What protective function is lost when operating P-8B from C-150/150A?
No LSPT, but there is a warning light to warn you that you only have 20 minutes of water supply left in T-2
How are the P-A/B AFW pumps flow control valves operated?
- air to close with nitrogen backup
- can be operated from the Control Room (normal), C-33, C-150, and locally in CCW room
- Control Room controller passes signal to C-33 controller. If C-33 controller is in auto, signal is passed on to the valves.
How are the P-8C AFW pump flow control valves operated?
- System contains two 4” normal CVs, and two 1.5” bypass CVs.
- 4” valves are air to close with nitrogen backup, can be operated from the Control Room (normal), C-150, and locally in WESG. Control Room controller passes signal to C-33 controller. If C-33 controller is in auto, signal is passed on to the valves.
- 1.5” bypass valves are the same as the 4” valves except they are air to open, and there is no control for them at C-150. To use the bypasses, need to ensure S/G pressure > 212 psia, or S/G level > 60%
What initiates AFAS?
S/G low level of 30% (2/4 logic)
What are the AFAS Sensor channels power supplies?
Y-10, 20, 30, 40
What are the AFAS Actuation channels power supplies?
D11-1 and D21-2
What happens on a loss of power to an AFAS sensor channel?
Loss of power causes sensor to trip (thinks there is a low S/G level)
What happens on a loss of power to an AFAS actuation channel?
Prevents AFAS from actuating on the channel that power was lost to
What is the start sequence of the AFW Pumps when AFAS is initiated?
- P-8A starts after 2.5 seconds
- P-8C starts after 30.5 seconds, if P-8A isn’t delivering 100 gpm to S/Gs, or is in manual
- P-8B starts after 112.5 seconds from the time P-8A failed to start or deliver flow, if P-8C isn’t delivering 100 gpm to S/Gs, or is in manual
What is required for A/B AFW pump flow controllers to be operable?
- Controller in CASCADE
- Controller in AUTO with no MFW, and S/G levels & PCS temperature within band
What are the modes of operation for the A/B AFW pump flow controllers?
- MANUAL - control valve position with slide bar (AFAS won’t work)
- AUTO - maintains flow at set point
- CASCADE - maintains flow at 165 gpm
What is required for C AFW pump flow controller to be operable?
- In CASCADE
- In AUTO
- In PF MODE
What are the modes of operation of the C AFW pump flow controller?
- MANUAL - control valve position with slide bar (AFAS won’t work)
- AUTO - maintains flow at set point. If AFAS occurs, controller will swap to CASCADE automatically
- CASCADE - maintains flow at 165 gpm
- PF MODE - controls 1.5” bypass valves, and controller swaps to AUTO control automatically
What is the ORM required action if 2 channels of AFW flow indication are lost?
Declare the associated AFW feed flow CV inoperable
What is a precaution associated with T-2 low level?
At 7.5% in T-2, place all AFW pump handswitches in Manual
What are the AFW pump limitations based on S/G pressure?
- P-8A/B can deliver required minimum flow with S/G pressure up to 1000 psia
- P-8C can deliver required minimum flow with S/G pressure up to 900 psia
When can AFAS be reset?
When both S/G levels are > 30%
