Auxilairy Feedwater(CA) Flashcards
What is the purpose of the Auxiliary Feedwater System?
- The Auxiliary Feedwater System provides a nuclear safety related source of emergency feedwater to the steam generators to maintain secondary side level, at times when the normal feedwater system is not available:
A. Removes Primary Coolant stored energy
B. Removes residual core energy
C. Prevents over-pressurization of the primary coolant system
D. Prevents primary coolant expansion(boiling) that could lead to fuel damage - Required to operate until the NC temperature is lowered to the point a which the Residual Heat Removal System(ND) may be operated(Mode 4 less than 350F)
- May be used as normal feedwater when less than 3% power
What is the system designator for the Auxiliary Feedwater System?
CA
What is the mission time for the Auxiliary Feedwater System?
7.5 days
What is the design/capacity of the Auxiliary Feedwater Motor Driven Pumps?
- 2 AC motor driven pumps per unit
- 100% capacity, each pump can supply all of the Auxiliary Feedwater requirements of 2 Steam Generators
- 490 gpm design flow
- Horizontally mounted, centrifugal pump
What is the power supply to the Motor Driven Auxiliary Feedwater Pumps?
ETA / ETB
Which Steam Generators are each Motor Driven Auxiliary Feedwater Pump aligned to?
A Pump - A and B Steam Generators
B Pump - C and D Steam Generators
What is the design/purpose of the Turbine Driven Auxiliary Feedwater Pump?
- There is one turbine driven pump per unit
- Capable of supply 100% of the Auxiliary Feedwater requirements
- Normally aligned to all four Steam Generators
- Design flow rate of 550 gpm
Where is the steam to the Turbine Driven Auxiliary Feedwater Pumps supplied from?
- Steam is supplied from the ‘B’ and ‘C’ Steam Generators, with one steam line supplying 100% of the requirements:
A. SA-2 from the ‘B’ Steam Generator
B. SA-5 from the ‘C’ Steam Generator - Steam can be supplied from the Auxiliary Steam system for testing
What is the normal position of the Auxiliary Feedwater Pump Suction Valves, and how are they maintained?
- The suction valves for all three pumps are open with power removed.
- The breakers are padlocked open to ensure they are not closed inadvertently
When will overspeed trip signals be generated for the Turbine Driven Auxiliary Feedwater Pump?
- Electrical Trip at 115% speed
2. Mechanical Trip at 125% speed
What is the correct way to trip the Turbine Driven Auxiliary Feedwater Pump?
Depress the manual trip lever locally at the CAPT
How is the Trip Throttle Valve Linkage reset for the CAPT?
The operator has to pull the trip linkage towards the Trip Throttle Valve.
What is the design/purpose of the Auxiliary Feedwater Discharge Flow Control Valves?
- Pneumatically operated, fail open valves
2. Following a CA Auto Start the FCVs will open to their travel stops
What is the number one preferred source of water for the Auxiliary Feedwater Pumps?
The Auxiliary Feedwater Condensate Storage Tank(CACST) - 42,500 gallons
What is the number two preferred source of water for the Auxiliary Feedwater Pumps?
The Upper Surge Tank(UST) - 85,000 gallonsd
What is the number three preferred source of water for the Auxiliary Feedwater Pumps?
The Condenser Hotwell - 161,000 gallons
Why is the Hotwell Isolation Valve to the Auxiliary Feedwater System, CA-2, normally maintained in open with power removed?
This ensures that a spurious closure of CA-2, CA-4(UST), and CA-6(CACST) such as might be caused by a fire doesn’t cause a loss of all Condensate to CA.
What is the number four preferred source of water for the Auxiliary Feedwater Pumps?
The assured source, and the number four preferred source, is Nuclear Service Water(RN)
What is the number five preferred source of water for the Auxiliary Feedwater Pumps?
The “sabotage proof” source, and the number five preferred source of water is Condenser Circulating Water(RC).
What conditions will cause Nuclear Service Water to automatically align to the Auxiliary Feedwater System?
- Each train has three suction pressure switches
- All three channels have a 5 second time delay to prevent actuation on the pressure drop following a normal system start
- 2/3 channels sensing low pressure will align the RN valves to the CA suction FOLLOWING AN AUTOMATIC INITIATION
What conditions will cause Condenser Circulating Water to automatically align to the Auxiliary Feedwater System?
- Each train has three suction pressure switches
- All three channels have a 5 second time delay to prevent actuation on the normal pressure drop following a system start
- 2/3 channels sensing low pressure will align the RC valves to the CA suction REGARDLESS OF WHETHER IT’S AUTO INITIATION SIGNAL OR A MANUAL INITIATION.
Where does recirculation flow from all of the Auxiliary Feedwater Pumps go?
The Upper Surge Tank(UST)
What are the automatic start signals for the Motor Driven Auxiliary Feedwater Pump?
- Safety Injection - Train Related
- Blackout - Train Related
- Steam Generator Narrow Range Lo-Lo Level - 2/4 channels Lo-Lo on 1/4 Steam Generators
- Loss of both normal Feedwater Pumps - 2/3 low FWPT control oil pressure starts both Motor Driven CA Pumps
- AMSAC - ATWS Mitigation System Actuation Circuit
A. Loss of CF Feed Path
B. Both CFPTs Tripped
What is the setpoint for the Unit 1 and Unit 2 Steam Generator LO-LO Level Motor Driven CA Pump automatic start?
Unit 1 - 11%
Unit 2 - 37%
What is the setpoint for the Loss of Both Normal Feedwater Pumps Motor Driven CA Pump automatic start?
Control oil pressure of less than 75psig on 2/3 channels
What is the setpoint for Loss of CF Feed Path(AMSAC) for the Motor Driven CA Pump automatic start?
Active when greater than 40% turbine load, and remains active for 2 minutes after turbine load decreases to less than 40%
- 3/4 CF Containment Isolation Valves closed(Unit 1 only)
- 3/4 Main Feedwater Regulating Valves less than 25% open with associated Bypass Valves less than 50% open for 30 seconds.
What are the Turbine Driven Auxiliary Feedwater Pump automatic starts?
- Blackout - ETA or ETB low voltage
- Steam Generator LO-LO Level - 2/4 channels on 2/4 Steam Generators
- Other starts:
A. Loss of power to the solenoids for the steam admission valves
B. 2/4 SSF Wide Range Steam Generator Levels less than 45% causes steam valve SA-5 to fail open
How will the plant respond to an Auxiliary Feedwater automatic start?
- S/G Blowdown Flow Control Valves close
- S/G Blowdown Containment Isolation and Containment Isolation Bypass Valves close(Train Related)
- Nuclear Sampling(NM) Containment Isolation Valves close(Train Related)
- Feedwater Containment Isolation Bypass Valves close
- Individual Feedwater Tempering Line Valves close
- CA Flow Control Valves go full open
- Low suction pressure swap of RN is enabled after 5 seconds
- SA-5 and SA-2(Main Steam to CAPT) valves fail open
- CAPT Governor to MAX
- Manual closing of the CAPT Trip Throttle Valve is prevented
- Normal Hotwell Makeup Valve, CS-47, fails closed to preserve the volume in the UST.
What is the power supply for the Motor Driven Auxiliary Feedwater Pumps?
ETA / ETB
What is the power supply to the CAPT Train A Sump Pump?
1EMXS
What is the power supply to the CAPT Trip Throttle Valve?
EDE
What is the power supply to CA-178 and CA-175, RC to CA Isolation Valves?
CA-178 - SMXG
CA-175 - 250VDC from the SSF Batteries
What is the power supply to CA-174, RC to CA Isolation Valve?
125VDC from SSF for the air solenoid
What is the affect of a loss of air on the CA Flow Control Valves?
The Flow Control Valves have accumulators sized to allow control of the Flow Control Valves for up to an hour following a loss of air.
