Aux Feedwater

Question 1

State the purpose of Aux Feed (AF).

Answer 1

1) Provide independent means of feeding steam generators during normal shutdown, startup, and emergency or accident conditions.

Question 2

What is the basis for the AF water reserve?

Answer 2

Provides enough feedwater to permit the plant to operate in hot standby (mode 3) for 8 hrs followed by an orderly plant cool down at a rate NTE 75F/Hr to the point where shutdown cooling may be placed in operation (RCS <350F).

Question 3

Draw AF.

Answer 3

Include all sources, valves, pumps, and discharge paths for all 3 AF pumps.

Question 4

Where can AF pump recirc flow be aligned to?

Answer 4

the CST only. If taking a suction of the RMWT, then there is potential for radiological contamination of the CST.

Question 5

What cools the AF pump rooms?

Answer 5

A & B are normally cooled by Aux bldg normal AHUs when they are in standby. Once started, they will be cooled by EC.
The N pump is in the turbine building, so no cooling is provided other than HT.

Question 6

Where does the Secondary Chemical Control system inject ammonia and hydrazine to?

Answer 6

the suction of AFN-P01.

Question 7

What is the power supply to AFN?

Answer 7

PBA-s03

Question 8

What is the power supply to all of the “B” train motor operated valves?

Answer 8

PH

Question 9

What are the steam supplies to AFA-P01?

Answer 9

Aux steam (overspeed uncoupled testing only)
SG

Question 10

Where do the drains for the AF pump rooms go?

Answer 10

Radioactive Waste Drains (RD). It can handle 200GPM from the rooms.

Question 11

What cools AFN-P01 oil coolers?

Answer 11

The oil is cooled by a slipstream of water from the pump first stage discharge.

Question 12

What are the sources of control power for AFN-P01 and how do you select which is to be used?

Answer 12

PKA and the A train class battery charger. There is a 3 position transfer switch located near PBA-S03.

Question 13

How does feed water get from AFN-P01 to the S/G?

Answer 13

through the downcomer control valves or the downcomer control valve bypass valves

Question 14

What position are the valves for the AFN pump suction usually in?

Answer 14

closed to protect the CST volume from a pipe shear in the non-seismic portion of the system.

Question 15

What interlock is associated with the AFN pump suction valves?

Answer 15

When valves are < 80% open the AFP won’t start and if it’s running, it will trip the pump if the valves go closed

Question 16

What are the differences between AFN-P01 and AFB-P01?

Answer 16

1) AFB is designed to meet seismic requirements.
2) AFB has a larger HP motor
3) AFB will autostart on a signal from the ESFAS load sequencer module.

Question 17

What is the power supply to AFA-P01

Answer 17

Steam from AS or SG

Question 18

What is the minimum pump speed required for the Terry Turbine to provide adequate lubrication to its bearings and water lubrication for the pump internals?

Answer 18

1000 RPM

Question 19

What cools the lube oil on AFA-P01?

Answer 19

the first stage of the pump provides the cooling water.

Question 20

When is the AFA-P01 pump used?

Answer 20

station blackout since it needs no AC power to run. It is also capable of delivering water to the S/G at a reduced flow rate and pressure as the RCS is cooled down to S/D cooling entry conditions.

Question 21

Where does the steam for the AFA-P01 pump come from?

Answer 21

it taps off u/s of the MSIVs in the SG system through motor operated isolation valves.

Question 22

Why is there a large condensing pot located within the Aux building for the AFA pump turbine?

Answer 22

to allow the turbine to fast start from cold conditions. If condensation were allowed to collect in the steam lines AFA could trip on overspeed during startup.

Question 23

What does the trip throttle valve do on the AFA pump turbine?

Answer 23

HV-54 is upstream of the steam admission valve and trips automatically on overspeed.

Question 24

How is the trip throttle valve reset after an overspeed trip?

Answer 24

the AO will have to manually reset it locally.

• control room closes steam supply vlvs
• AO verifies HV-54 closed
• AO ensures latch up lever and trip hook are aligned
• AO pulls the reset lever toward the trip throttle valve to reset the trip
• AO releases and ensures no gap between latch lever and trip hook
• AO makes sure the trip actuator button is pushed down to hold the reset lever and makes sure the trip lever is in the reset position

Question 25

How many locations can the TTV be operated from?

Answer 25

3 - locally, control panel, & remote s/d panel
There are also pushbuttons to allow tripping remotely as well. If tripped remotely, no need for AO to reset since it just dumps control oil.

Question 26

What is the power supply to the AFA-P01 regulating and isolation valves that are located in the discharge piping?

Answer 26

PK

Question 27

What is the power supply to AFB-P01 downstream regulating and isolation valves?

Answer 27

PH (Class 480VAC)

Question 28

How are the isolation valves protected from pressure locking?

Answer 28

a relief valve installed on the bonnet of the valve vents to the CST via the mini flow lines for the respective pump.

Question 29

What is the AFAS setpoint?

Answer 29

25.8% WR level in a S/G.

Question 30

What band will the isolation and flow control valves cycle to maintain on an AFAS?

Answer 30

25.8%-40.8%

Question 31

What is the difference between AFAS-1 and AFAS-2?

Answer 31

The automatic actions are the same, except that only the isolation and flow control valves associated with S/G#2 will be auto cycled (4 valves).

Question 32

What is the “delta-P lockout”?

Answer 32

If the D/P between #1 & #2 S/Gs is > 185 psid, then a signal is generated to prevent the lower pressure S/G isolation and flow control valves from opening. This prevents feeding a S/G that has a steam or feed rupture. It will close the isolation valves for the lower pressure S/G if they are open.

Question 33

Which AF pump is used for normal startup?

Answer 33

AFN is used until rx power reaches 2%. Then a main feed pump is started.

Question 34

Why are the temperature indicating strips located on the discharge piping of each AFW pump?

Answer 34

To monitor for the presence of steam in the line which would be indicated by an elevated temperature. Steam binding could occur as well as water hammer if steam were present and the pumps attempted to start.
Blue/Green indicated elevated temperature