Auxiliary Feedwater System

Question 1

What is the Basis for the amount of AF that is reserved for use in the plant during emergency situation?

Answer 1

Provides sufficient reserve of feed water to permit the plant to operate in mode 3 for 8 hours followed by an orderly plant cool down rate not to exceed 75F/HR to the point where shutdown cooling may be placed in operation (RCS temp 350F)

Question 2

What is the capacity of the CST and RMWT?

Answer 2

CST 550,000

RMWT 480,000

Question 3

How is HA affected by a high water level in either AF pump room?

Answer 3

Aux building AHU dampers isolate the rooms

Question 4

How is ‘N’ AFP self lubricating?

Answer 4

Uses dipper rings to throw oil onto the bearings

Question 5

What provides cooling water for AFP lube oil coolers?

Answer 5

Pump first stage discharge

Question 6

Where is AF ‘N’ powered from?
Control power?

Answer 6

PBA-S03

Control power - has 2 sources PKA-D21 and ‘A’ battery charger

Question 7

Why does the AF ‘N’ have 2 class powered suction valves?

Answer 7

Provide class and seismic protection boundary for CST inventory, separating it from the non-seismic piping to AF ‘N’ downstream isolation valves. (CTA-HV-4 & CTA-HV-111)

Question 8

Where are the AF ‘N’ class power valves located and what is there designation?

Answer 8

CST pump house (CTA-HV-4 & -1)

Question 9

What is the interlock associated with AF ‘N’ and its suction valve? What is the purpose?

Answer 9

If either valve (CTA-HV-4 & -1) is less than 80% open then the pump will not start and will trip if running

Purpose is to provide protection from a low suction pressure condition, which could damage the pump

Question 10

Where are all the non-seismic penetrations located on the CST?

Answer 10

Above the safety storage volume of 330,000 gallons or 29.5 feet

Question 11

What is the difference between AF ‘N’ and ‘B’ even though they are similar pumps?

Answer 11

‘B’ designed to meet seismic requirements

‘B’ equipped with a larger horsepower motor (125% larger)

‘B’ equipped with auto start feature from the ESFAS load sequencer module of the BOP ESFAS that will start under certain conditions

Question 12

What happens when the AF ‘B’ ‘A’ start?

Answer 12

Essential air cooling unit auto starts

Question 13

What is the purpose of the AF ‘A’ worm drive gearbox?

Answer 13

Coupled to an oil pump and the turbine governor actuator and driven off the turbine

Question 14

What provides cooling water to the AF ‘A’ lube oil cooler?

Answer 14

First stage of the AFP

Question 15

What is the minimum speed of AF ‘A’ pump to provide adequate lube and cooling?

Answer 15

1000rpm

Question 16

How do we maintain the cleanliness of the AF ‘A’ governor control system?

Answer 16

Renewable cartridge filter that has a built in dirt alarm that will auto bypass the filter when it becomes clogged

Question 17

How does the AF ‘A’ respond to AFAS?

Answer 17

SGA-UV-134A and -138A open first to bring the turbine up to speed in a slow and controlled manner

30 seconds later SGA-UV-134 and 138 open to allow maximum steam flow to the turbine and as the turbine approaches nominal speed, governor begins to throttle governor control valve to 3600 rpm

Question 18

Why is there a large condensate pot installed in the Aux Building?

Answer 18

To allow constant draining of moisture that accumulates in the steam supply line

Without it moisture could accumulate in the steam supply line and greatly increase the chance of turbine overspeed during startup

Question 19

Where can I trip AFA-HV54 electrically?

What is AFA-HV54?

Answer 19

Board 6 in the control room

‘A’ remote shutdown panel

local control panel

It is the steam supply valve to the ‘A’ AF turbine AFA-k01

Question 20

What is a trip of AFA-HV-54?

Answer 20

Mechanical overspeed device

Question 21

What is the purpose of the AF regulating and isolation valves?

Answer 21

Provides means to regulate and isolate flow, respectively to the steam generators from the essential AF pumps

Question 22

What powers the regulating and isolation valves associated AF ‘A’?

Answer 22

PKA and PKC

Question 23

What is pressure locking in regards to double disk gate valves?

Answer 23

When a valve is closed and water gets trapped and thermal expansion locks the valve

Question 24

How do we prevent pressure locking?

Answer 24

Each ‘A train isolation babes bonnet area is connected to a relief valve that relieves to the CST, normally via ‘A’ AFP mini-flow line

‘B’ has an equalizing valve on the bonnet and discharges to the side of these valves

Question 25

What happens when an AFAS is received and what initiates it?

Answer 25

Generated by PPS when applicable steam generator water level has lowered to 25.8%

Both Essential AF pumps start and affected SG regulating and isolation valves open

When level in the SG reaches 40.8% the applicable regulating and isolation valves are open

Question 26

What happens if SG pressures differ by more than 185psid?

Answer 26

The DP lockout will close the regulating and isolation valves for the affected SG and prevent them from being reopened

Question 27

What is the power supply of AF ‘B’?

Answer 27

PBB-S04

Question 28

During startup, up to what power will we maintain SG levels with AF?

Answer 28

2%