Auxiliary feedwater

Question 1

Purpose of AFW system

Answer 1

1. Provide heat sink upon loss of off site power
2. Cool RCS down to <350F from RHR operation

Question 2

Design basis of AFW system (5 items)

Answer 2

1. Provide FW to the SG to remove decay heat (requires 420 gpm).
2. Flow limiting orifice - ensures that in the event of a line rupture at least 160 gpm to intact SG
3. Deliver flow within one minute of accident (ATWS)
4. No operator action necessary for 30 minutes
5. Pump design capacity of 990 gpm @ 1450 psig (assumes 100 gpm recirc flow).

Question 3

Auto starts of AFW pumps (5)

Answer 3

1. Any SI
2. Low-low SG level; 2/4 detectors in 1/4 SGs U1 18% U2 36.3%
3. UV on 2/4 RCP busses
4. A AF PP (only) starts on UV on bus _41 (35 sec TD EDG bkr)
5. AMS actuation; A AF Pp auto start is disabled for 70 seconds following bus _41 UV U1 15% U2 33.3%

Question 4

A AF pump trips

Answer 4

1. Overcurrent
2. Low-3 suction pressure of 16.5 psia; disabled for 2.5 seconds during start
3. UV on bus 141 (2870VAC)

Question 5

B AF pump trips (Diesel) (five)

Answer 5

1. Low-3 suction pressure of 16.5 psia
2. Overcrank (<350 rpm in 55 seconds)
3. Overspeed (1900 rpm)
4. High jacket water temperature (205F)
5. Low engine lube oil pressure (10 psig) disabled for 10 seconds during start.

Question 6

What are the positions of B AF pump local C/S and what do they do?

Answer 6

Manual- starts in room only
Off- Won’t start from any location
Auto- Start from all locations (MCB, RSDP, AB 364’ column M-16)

Question 7

What are the positions of the Diesel start switch from 364’ elevation and what do they do?

Answer 7

Normal - allows start from normal locations
Start - Start remotely with suction pressure greater than lo-lo suction trip
Start with bypass - Start remotely with suction pressure less than lo-lo suction trip

Question 8

Diesel start sequence and overcrank description:

Answer 8

5 second crank, 10 second wait (repeat).
If not running after 55 seconds, engine locks out with a reset P/B at the local panel

Question 9

AF006 and AF017 (SX supply to AF suction) need all of the following to auto open:
What is the time delay for A train?
Do the pumps need to be running for valves to open?

Answer 9

1. Auto start signal (Excluding AMS and 141 UV) SI, or low-low SGWL or UV on 2/4 RCP busses
2. Low suction pressure of 18.1 psia
3. For A-train: 4 second time delay after pump start signal
4. For B-train: Pp does not need to be running and no time delay.

Question 10

AF022A/B and AF024 (normal recircs and recirc to SX) description

Answer 10

Recirc also auto swaps to SX: AF022 closes when own SX suction valves (both) not fully closed AF024opens when either AF022 not fully open. When AF006s and AF017s are closed. The recircs automatically re-align (AF022s open and AF024 closes).

Question 11

AF005s (discharges to all 4 SGs)
Loss of air ______
Loss of Inst bus 111 (A) or 114 (B)_____
Loss of DC bus 111/112______

Answer 11

Fail open on loss of air

Control signal to zero flow, once pp starts for respective train, associated AF005s fully close to obtain zero flow. Control from RSDP still available in local.

Can’t control AF005s from RSDP or MCR for the associated train.

Question 12

AF005s potentiometer set @_____ for a flow of _____, alarm if the pot is <_____.

Answer 12

6.8
170 gpm
6.7

Question 13

B train flow lights >_____ gpm, >_____ gpm. Powered from DC bus _____.

Answer 13

80 gpm
160 gpm
DC bus 112

Question 14

Affects of a loss of DC bus 112(212) to the B AF Pp:

Answer 14

1. 80 gpm and 160 gpm flow lights are lost.
2. The Pp will not autostart from any autostart signal or from the MCB or RSDP C/S.
3. The only way to start the B AF Pp on a loss of 112 DC is from the local panel or from the C/S on 364’ elevation.

Question 15

AF004A/B are the _______, get a signal to open when _____, fail ____ on loss of air and has own air receiver to _____ on low air pressure (70#).

Answer 15

Normally open AF pump discharge valves
Start when respective AF pump starts
Fails as is on loss of air
has own air receiver to auto open on low air pressure

Question 16

AF suction pressure setpoints:
AF051/055 (suction of pumps)

Answer 16

47 psia Resets block of associated AF pump start
20.1 psia Low pressure alarm
18.1 psia Low pressure auto swap suction to SX if auto start present
16.5 psia Lo-2 Pps trip (2.5 sec time delay on A train)

Question 17

AF suction pressure setpoints:
AF300/301 (CST to AF line)

Answer 17

20.46 psia Blocks associated train AF pump start
Arms SX suction valves (AF006 and 017)

Question 18

Purpose of flow limiting orifices on the discharge lines.

Answer 18

Limit break flow so that other SGs will get >160 gpm each and provide AF Pp runout protection.

Question 19

Diesel AF pump flex bypass switch details:

Answer 19

Normal allows remote start.
Flex bypass removes low pressure pump start block signal.
Start with bypass starts the pump.

Question 20

Engine start control switch must be in ______ to allow start from _____, _____, or ______.

Answer 20

Auto
MCB, RSDP, or 364’ C/S

Question 21

364’ C/S details. The ______ position will disable the _____.
Control switch must be returned to _____ to allow _____.

Answer 21

Start with bypass position; Suction pressure trip

Normal position to allow remote pump shutdown.

Question 22

The B train flow lights (>80gpm, >160 gpm) are located on ____.

Answer 22

1pm06j

Question 23

Diesel AF pp specs

Answer 23

1500 HP, 16 cylinder, 10 stage pump

Question 24

SX interfaces with diesel AF pump

Answer 24

Self driven SX booster pump (needs a flow path, but no SX pump required).
Speed increaser, oil and water jacket cooled by SX

Question 25

There are ____ sets of batteries for the diesel AF pump. One normally in service for starting and the other reserved for ____. Each bank is sufficient for _____ cranking cycles of 55 seconds each.

Answer 25

2 sets of 24 VDC batteries Control power 4

Question 26

Fuel oil specs

Answer 26

500 gallon tank, 75%/420 gallons TS minimum, 50% pp running minimum. Burn rate of 70 gph at max rate.

Question 27

Pump oil pressure must be ____ and gear oil pressure ____ for starts from _____ and _____.

Answer 27

8# 15# MCR and RSDP

Question 28

Diesel AFP can be started from what 4 locations?

Answer 28

MCB RSP Pump room on 383' U1: C/S on 364' between CC HX U2: C/S on 364' M18

Question 29

AF005 From MCR: sets _____ From RSP: sets ______ Local handwheel _____

Answer 29

Flow demand signal Sets valve position (must energize to select local first) Operated from 364' (fail air first)

Question 30

Two AF trains must be operable in modes ______. IF one inoperable _____ to restore. If both inoperable _______. LCO 3.0.3 _____.

Answer 30

1, 2, and 3 72 hours restore one immediately LCO 3.0.3 and all other LCO Required Actions requiring MODE changes are suspended until one AF train is restored to OPERABLE status. ---------------------

Question 31

AF013A-H are _____ operated valves with the following operation limitation_____.

Answer 31

Motor Throttleable motor driven, duty= 3 starts in 1 minute

Question 32

CST level bases: Accident analysis_____ Tech spec Basis______

Answer 32

Accident analysis assumes that there is enough water to remove decay heat from a 102% trip, stay in MODE 3 for 30 minutes and cooldown to RHR at the design cooldown rate, with a loss of offsite power and “the most adverse single failure” TS Basis Document: 212,000 gallons will maintain RCS stable at NOT/NOP for 2 hours, then cooldown to RHR entry conditions at 50F/hr, and allow a 1 hour warmup of the RHR pumps before beginning shutdown cooling

Question 33

For AF006 and AF017 to auto open, the control switch must not be in ____ and the ___ signal must be present.

Answer 33

Close Arming

Question 34

PS-AF-300/301 reaches pressure of ______ psia and PT-AF-051/055 reaches pressure of _____ psia are inputs to the ______ annunciator.

Answer 34

20.46 psia 18.1 psia AF PP SX SUCT VLVS ARMED ALARM

Question 35

_AF006 and _AF017 will Auto Open if:

Answer 35

Control switch – not in CLOSE AND AF PUMP SX SUCT VLVS ARMED annunciator LIT AND 2/4 Lo-2 SG Level (1/4 SG) OR 2/4 RCP bus undervoltage OR Any SI

Question 36

To reset the 20.46 psia AF block signal, pressure must be raised to ______.

Answer 36

47 psia

Question 37

A AF pump control switches and locations:

Answer 37

Main Control Board Remote Shutdown Panel Local/Remote Switch at Remote Shutdown Panel

Question 38

Sequence of manual start for the A AF pump:

Answer 38

1. Control Switch to “START” 2. Aux Lube Oil Pump starts 3. When pump lube oil pressure is > 8 psig 4. AF pump breaker will close and pump should start Note that breaker closing keeps aux lube oil pp running 5. When shaft driven lube oil pump raises lube oil pressure to > 15 psig, aux lube oil pump stops

Question 39

Sequence for auto start of A AF pump

Answer 39

1. AUTO signal received 2. AF Pump and Aux Lube Oil Pump start at the same time 3. When lube oil pressure > 15 psig, aux lube oil pump stops

Question 40

To clear a diesel AF pump lockout, There is a ____ and a local ______.

Answer 40

PB reset at the local control panel Reset device near air intake manifold

Question 41

B AF pump manual starting sequence

Answer 41

C/S held in start _B AF pp aux. L.O. pump starts At the same time, speed increaser aux. lube oil pump starts When oil press > 15 psig for speed increaser and oil pressure > 8 psig for the _B AF pp lube oil system, _B AF pump starts Shaft driven pumps operate When oil press > 23 psig for speed increaser its aux lube oil pump stops When oil pressure > 15 psig in _B AF pp lube oil sys, its aux lube oil pump stops

Question 42

B AF pump starting sequence

Answer 42

AF pump starts At same time both speed increaser and _B AF pp aux oil pps start When oil press > 23 psig for speed increaser its aux L.O. pp stops When oil pressure > 15 psig in _B AF pp L.O. Sys., its aux L.O. pp stops

Question 43

_____ gpm will bring in a high AF flow alarm.

Answer 43

190 gpm

Question 44

CST recirc valves fail ______ and SX recirc valves fail _____ on loss of power or IA.

Answer 44

Open Closed