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Essential Cooling Water(EW) Flashcards

1
Q

What do the Essential Cooling Water(EW) do ?

A

-EW cools heats loads of the RC system
-EW cools Essential Chillers in the Essential Chilled Water system
-EW cools SFP during Forced Shutdown & accident conditions OR when normal NC cooling is lost
-EW transfers heat load of containment atmosphere under accident conditions
-EW is used to cool NC priority loads under normal conditions, normal shutdown, or LOP when NC cooling is UNAVAILABLE

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2
Q

How is the Essential Cooling Water system designed ?

A

-Two independent,redundant,closed loop, trains
-Either train is capable of 100% required for safe shutdown or LOCA

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3
Q

What’re the components for each flow train ?

A

-Surge Tank
-EW pump
-Heat Loads
-EW Heat Exchanger
-Chemical Addition Tank

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4
Q

Why does Essential Cooling Water operate at a lower pressure than Spray Pond system ?

A

It’s to prevent leakage from the EW system & minimize environmental contamination
-Spray ponds will leak into EW system

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5
Q

How would you be able to detect leakage from Spray Pond into the EW system ?

A

There will be a level increase inside the Essential Cooling Surge Tank

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6
Q

What’re the EW cross connect flow paths ?

A

-EW used as backup cooling for SFP HEX if NC is unavailable
-EW can be cross connected to cool NC Priority Head Loads

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7
Q

What happens to EW train operability if EW is cross connected to NC Priority Head Loads ?

A

-The train that is selected to cool NC priority head loads will become inoperable

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8
Q

What is different about the ‘A’&’B’ trains Isolations Valves for the NC Crosstie for Priority loads ?

A

-Train ‘A’ has Motor Operated Isolation Valve
-Train ‘B’ has Manually Operated Isolation Valves

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9
Q

What must be done if one train of EW is used for backup cooling source for SFP HEX ??

A

If current mode requires a operable EW train, THEN opposite train need to be operable since the selected trains Essential Chiller will be inoperable due to Refrigerant Head Pressure Control Valve be manually overridden during flow balance

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10
Q

How does Class 4.16kV (PB) interface with Essential Cooling Water(EW) ?

A

PB provides power to EW pumps

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11
Q

How does Essential Cooling Water interface with Class 480VAC MCC(PH)?

A

PH provides power to Train ‘A’ Essential Cooling Water NC Priority Head loads crosstie MOVs

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12
Q

How does EW interface with PK system ?

A

PK provided power to EW system surge tank solenoid valves

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13
Q

How does EW interface with Instrument Power 120VAC (PN) ?

A

PN supplies power to EW instrumentation

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14
Q

How does Chemical Waste(CM) System interface with EW ?

A

-Alternate Backup Makeup Water source to the EW system from cooling water holdup tank
-Cooling Water Holdup Tank receives EW surge tank relief valve & drain valve
-EW HEX rooms each have one floor drain routing to cooling water holdup tank

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15
Q

How does EW system interface with Condensate Transfer & Storage (CT) ?

A

CT is the Primary BACKUP Makeup water to EW system

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16
Q

How does EW interface with Demineralized Water System(DW)?

A

DW system is the NORMAL makeup water source for the EW system

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17
Q

How does EW interface with Essential Chilled Water (EC)?

A

-EW removes heat from Essential Chillers in the EC system
-EC provides chilled water to EW pump room ACU

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18
Q

How does EW interface with Safety Equipment Status(ES) ?

A

EW provides output signals to ES system which monitors & alerts Control Room of Safety Equipment Inoperable Status & Safety Equipment Actuation Status(SEAS)

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19
Q

How does Essential Cooling Water(EW) interface with Fire Protection system ?

A

FP may be used as emergency makeup water source to EW system

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20
Q

How does EW interface with Service Gas(GA) system?

A

GA provides nitrogen play to the EW Surge Tank to prevent corrosion

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21
Q

How does Essential Cooling Water interface with Aux. Building HVAC(HA)?

A

EW pump room is cooled by Aux Building HVAC
-EW pump room ACU starts when pump starts
-ACU required to be operable for EW pump room equipment to be OPERABLE

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22
Q

How does Essential Cooling Water interface with Oily Waste(OW) system ?

A

-EW HEX Tube Side pressure relief valve is directed to floor drain which is routed to Control Building sump

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23
Q

What is the normal status of the EW HEX rooms floor drains ?

A

-These drains are normally plugged
-During outages plugs are removed to drain Spray Pond side of EW HEX

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24
Q

How does EW interface with Nuclear Cooling(NC)system ?

A

-EW can be cross tied to NC priority loads if NC is unavailable
-EW can be cross tied NC system to provide cooling to PC Cooling HEX

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25
When is EW crosstied to NC system for cooling to the PC Cooling HEX ?
-Done normally during outage for one PC Cooling HEX if NC is unavailable -Designed to be cross tied within 8hrs of loss of NC in an emergency
26
How is EW interface with Fuel Pool Cooling & Cleanup(PC)System?
EW removes heat from PC Cooling HEX during a LOOP or when NC is unavailable -During refueling outages when core is offloaded into SFP, EW is routinely used to cool one PC Cooling HEX
27
How does EW system interface with Plant Computer(RJ) system?
RJ system provides Control Room operators additional info to assist in operation of plant
28
How does EW system interface with Plant Annunciator(RK) system ?
RK system alerts operator in Control Room of major off-normal conditions & changes in EW system
29
How does the EW system interface with Engineered Safety Feature Actuation System(ESFAS) ?
-‘A’ train Motor Operated Crosstie valves receive close signal on SIAS -EW pumps actuated on LOP/Load Shed stops the pumps, & Load Sequencer Starts the pumps
30
How does EW interface with Emergency Response Facilities Data Acquisitions & Display (SD) systems ?
EW provides output signals to ERFDADS as indications for emergency response purposes
31
How does EW interface with Safety Injection(SI) system ?
-EW cools SDC HEX during cooldown, cold shutdown,& cools containment spray during accident conditions
32
How does EW interface with Essential Spray Pond
EW is cooled by spray pond water via EW Heat Exchanger
33
How does EW interface with Radiation Monitoring(SQ) system ?
-SQ provides radiation monitoring to EW & provides high EW radioactivity alarm to detect inter system leakage -One radiation monitor installed bypass loop around each of EW pumps to monitor trains gross gamma activity
34
How does EW interface with BOP analog instrument system Remote Shutdown Panel?
-Provides EW pump during times of Control Room uninhability -Panel contains Train B disconnect switch to separate B Remote Shutdown Panel from Control Room
35
What’re the EW pumps rated to do ?
Rated flow:16,650gpm Powered from Class 4.16kV (PB)
36
Where are suctions connected to ? What is the normal position of the suction & discharge valves for the EW pump ?
-Each EW pump takes suction from their own Surge Tank -Manual suction & discharge valves are locked open
37
What signals will automatically start EW Pumps ?
-LOP; EW pumps starts 20 seconds after EDG output breaker closes -CSAS -SIAS -CREFAS -CRVIAS -AFAS 1/2
38
What kind of protection does the EW pump motors happen ?
Provided with over-current & ground fault protection trips which will actuate 86 lockout relay
39
What else will start when the EW pump starts ?
Associated EW pump room ACU, cooled by Essential Chilled Water to ensure pump operability
40
What does the EW heat exchanger do ?
Spray pond is used to transfer heat from EW system inside the EW heat exchanger
41
What temp is the outlet of the EW HEX supposed to be ?
EW outlet temp is designed to be <135F
42
What is done to prevent leakage into the spray pond system ?
-EW operates at lower pressure than Spray Pond system -Prevents radioactive fluid from escaping into Spray Pond
43
What kind of overpressure protection is there on the EW HEX ?
-Relief valves are provided for shell side for over pressure protection
44
What’re the EW Surge Tanks used for ?
-Expansion & contraction to ensure adequate NPSH for EW pump -Convenient for addition of Makeup Pump
45
What is the capacity of each surge tank ? What is the rated pressure ?
-1000gallon capacity -Rated to 15psig
46
What kind of connections are provided for each EW Surge Tank ?
-Makeup water addition -Over pressure protection -Under pressure protection -Nitrogen Gas Addition -Level&pressure instrumentation
47
What is installed for level instrumentation ?
Level gauge glass & vapor space pressure instrument is installed locally for each Surge Tank
48
What’re the makeup water source to the EW Surge Tank ?
-Demineralized water Primary source -Condensate Transfer Primary BACKUP -Cooling Water Holdup Tank in Chemical Waste system Alternate BACKUP -Fire protection emergency backup
49
What signal will automatically shut solenoid operated makeup valve ?
A LO-LO level in the EW surge tank will auto shut solenoid valve to prevent feeding of a leak in the EW system
50
What does the Solenoid Operated Makeup Valve control makeup from ?
Solenoid makeup valve controls flow coming from Demineralized Water & Condensate Transfer & Storage
51
What is used for Over pressurization & under pressurization protection ?
Two pressure safety valves; one for over pressure & one for under pressure
52
What’re the two conditions that’ll close the ‘A’ train EW to NC motor operated crosstie valves to ensure EW can perform safety function ?
-EW ‘A’ Surge Tank LO level -SIAS
53
What is the EW Chemical Addition Tanks used for ?
-Provides a place for addition of corrosion inhibiting chemicals into the EW system
54
What is the normal condition for the EW chemical addition tanks? What is the capacity of the Chemical Addition Tanks?
-Chemical Addition Tank is normally isolated -11gallon tank
55
How’re the chemicals mixed into the EW system ?
-Chemicals dissolved inside addition tank before being released -Contents are flushed into EW system by diverting portion of EW pump discharge through tank & then back to EW pump suction
56
What do the Essential Cooling Radiation Monitors provide ?
-Non safety related radiation monitors to EW system -Alarm of high EW radioactivity as a predictor of inter-system leakage
57
Where does Radiation Monitor take its reading from ? Where does it alarm ?
-Flow through monitor come from discharge of EW pump & is retuned to EW pump suction -Monitors gross gamma activity
58
What is the Essential Cooling Water to Nuclear Cooling water crosstie valves used for ?
EW provides cooling for NC priority loads when NC is unavailable
59
What conditions can EW provide cooling for NC priority loads?
-Normal operation -Normal shutdown -Loss of Power(LOP)
60
Prior to cross connecting EW to NC priority loads, what must be done to the NC Non Priority Heat Load Isolation Valve ?
NC Non-Priority Heat Load Isolation Valve must be closed, to prevent transferring EW water into NC system
61
What will automatically close the Motor Operated isolation for EW to NC crosstie valve on ‘A’ Train?
-SIAS -Train ‘A’ EW LO Surge Tank Lvl
62
When cross connected what status should you consider EW safety related equipment ? What class is EW & NC in?
-The train that is cross connected to NC Priority Head loads shall not be considered OPERABLE -EW is a Q class system cool by ultimate heat sink -NC is a NQR rated system
63
What’re the NC priority loads ?
-Normal chillers One one chiller is cooled bye EW crosstie -Nuclear Sample Coolers -Control Element Drive Mechanism Air Cooling Units(CEDM ACU) -RCPs: High Pressure Coolers Seal coolers Thrust beating coolers Lube oil coolers
64
When is EW cross ties to the SFP Cooling HEX used ?
-Forced shutdown -accident conditions -When normal NC is unavailable
65
What is the process for lining up EW to the SFP Cooling HEX?
1.)Must isolate SFP Cooling HEX from NC system 2.) EW normally locked valve can, then be unlocked & opened to supply EW to SFP Cooling HEX
66
What impacts would the plant have on a LOSS of Essential Cooling Water(EW) ? When shutdown what will happen on loss of EW ?
-If one train of EW, becomes inoperable a shutdown will be performed -Will be a loss of cooling for SDCHX to the associated that was lost
67
What would happen on loss of PB 4.16Kv to the EW system ?
PB bus would load shed EW pump & would sequence back on from the DG
68
What would happen on a loss of PH 480VAC MCC to the EW system ?
You would lose power to ‘A’ train Motor Operated Isolation Valves
69
What would happen on a loss of PK 125VDC to the EW system ?
-Loss of channel ‘A’ or ‘B’ would remove power to Solenoid Makeup Valve that supplies Makeup Water to EW Surge Tank
70
What would happen on loss of Demineralized Water to the EW system ?
-Would lose normal source of Makeup to the EW Surge Tank -Would need to have operator align backup Makeup source
71
What would happen on a loss of Essential Chilled Water for the EW system ?
Loss of EC would make respective train EW pump room inoperable due to loss of the pump rooms ACU
72
What would happen on a loss of Service Gases to the EW system ?
-Would lose nitrogen blanket in EW surge tank & overtime would have Corrosion
73
How does loss of Aux. Building HVAC affect EW system ?
Loss of EW Pump Room ACU makes EW pump & train inoperable
74
How would a loss of NC affect EW system ?
-Would have to realign EW to NC priority loads would make that respective EW Train INOPERABLE
75
How does loss of Spray Pond affect EW system ?
Loss of Spray Pond would make respective Train EW INOPERABLE
76
How would a loss of Radiation Monitoring System(SQ) affect EW system ?
-Radiation Monitor is offline then chemistry will have to grab samples
77
How many EW trains should be operable during modes 1-4 ?
Two EW trains shall be Operable in MODES 1-4
78
When is needed for EW train to be considered OPERABLE ?
-Associated Pump & Surge Tank OPERABLE -Associated piping,valves,& instrumentation and control to perform safety related functions OPERABLE
79
Where Essential Chilled water supplied to ?
Supplied to ESF ACUs & AHUs in the Control building & Aux. Building, when normal chilled is UNAVAILABLE & upon ESFAS signals

Systems (62 decks)

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