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EW-Essential Cooling Water System Flashcards

1
Q

What is the purpose of the Essential Cooling Water system?

A

1 Xfr residual heat from RCS to atmosphere
2 Xfr environment heat from essential chiller to atmosphere via the SP
3 Xfr decay heat from SFP to atmosphere via the SP, when NC unavail.
4 Xfr heat from containment to atmosphere via SP
5 Xfr NC heat norm removed by NC system to atmosphere via SP when NC unavail.

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2
Q

What is the design of the Essential Cooling Water system?

A

2 independent trains, closed loop, either train can support 100% of the cooling for safe shutdown.
Major components: surge tank, EW pump, Heat loads, EWHX, Chem add tank.

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3
Q

What is the normal flow path of the Essential Cooling Water system?

A

EW Pump discharges to both Essential chiller and SDCHX->Shell side of the EWHX xfr heat to SP-> back to suction of the pump.

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4
Q

What is the flow path for Esscential Cooling water when it is cross connected to the NC system?

A

Usually A train to A train via crosstie. This means you must have B train EW operable to remain in tech specs.

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5
Q

What is the difference between ‘A’ train and ‘B’ train Essential Cooling water valves?

A

‘A’ has motor operatedisolation valves while ‘B’ has manually operated isolation valves.

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6
Q

What powers Essential Cooling Water system pumps, valves, and instrumentation?

A

PB-powers the pump
PH-powers EW to NC Train ‘A’ crosstie valves
PK-Powers surge tank solenoid valves
PN-Powers system instrumentation

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7
Q

How does the Chemical Waste System (CM) interact with the Essential Cooling Water system?

A

CM is a backup makeup water supply to the EW system from the Cooling Water Holdup Tank.
Cooling Water HUT in CM receives EW when EW surge tank overpress valves lifts
or out the EW surge tank drain valve.
The EWHX rooms have floor drain to the Cooling Water HUT.

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8
Q

How does the Essential Chilled Water System (EC) interact with the Essential Cooling Water system?

A

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

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9
Q

How does the SAfety Equipment Status System (ES) interact with the Essential Cooling Water system?

A

EW provides output signals to the ES system which monitors & alerts the CR of safety equipment inoperable status and/or safety equipment actuation status.

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10
Q

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

A

The EWHX tube side (SP) press relief valve goes to floor drain that is routed to Control Bldg sump. Drains have plugs normally installed. During outage plug removed for draining the SP side of he EWHX to the cntrl bldg sumps.

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11
Q

How does the Nuclear Cooling Water System (NC) interact with the Essential Cooling Water System?

A

EW can be cross-tie to the NC system to provide backup cooling for NC if NC unavail.
EW can be cross-tie to NC to provide colling to the PC Cooling HX.
Normally in outage. Designed to be done w/i 8 hrs of a loss of NC.

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12
Q

How does the Fuel Pool Cooling and Cleanup System (PC) interact with the Essential Cooling Water System?

A

EW removes hat from the PC system during LOOP or when norm cooling water from NC is unavail.
During outage EW used to cool one of the PC cooling HX.

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13
Q

How does a Engineered Safety Feature Actuation System (SA) interact with the Essential Cooling Water System?

A

‘A’ train MOV cross-ties recieve a closed signal upon a SIAS.
EW pumps are started on a SA signal (LOP/Load Shed stops pumps, Load Sequencer starts pumps.)

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14
Q

How does the Safety Injection System (SI) interact with the Essential Cooling Water System?

A

EW supplies cooling water to the SDCHX to remove RC core decay heat during cooldown and cold shutdown.
Also cools CS during an accident.

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15
Q

How does Radiation Monitoring system (SQ) interact with the Essential Cooling Water System?

A

SQ provides non-safety related radiation monitoring to the EW system. One radiation monitor by each EW pump to monitor trains for gamma activity.

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16
Q

How does the BOP Analog Instument System (ZJ) Remote Shutdown Panel?

A

Provide op ofr EW Pump during time when the CR is offline. Panel has ‘B’ train disconnect swiches to separtate the B Remote shutdown panel from the CR.

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17
Q

What is the purpose of the Essential Cooling Water Pumps?

A

Supply water to the EW system components at the required flow rates.

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18
Q

What is the design of the Essential Cooling Water Pumps?

A

Horizontal, CP, Single stage, double suction, rated flow 16,650 gpm, powered by Class PB 4.16 kV.
Takes suction from its dedicated surge tank directing flow to their respective EW heat loads. Normally locked open manual valves at suction and discharge for isolation.

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19
Q

What are the automatic features associated with the Essential Cooling Water Pumps?

A

Pumps will auto-start on:
LOP to PBA/PBB, CSAS, SIAS, CREFAS, CRVIAS, or AFAS 1 & 2.
Pump motors have over-current ground fault protection trips (86 lockout)
EW pump start will start associated EW pump room ACU cooled by Essential Chilled Water (EC).

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20
Q

What is the purpose of the Essential Cooling Water Heat Exchangers?

A

Transfer heat gained from the EW system loads to the Spray Pond system.

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21
Q

What is the design of the Essential Cooling Water Heat Exchangers?

A

1 for each train, single pass, shell and tube, SP in tubes and EW in shell. EW outlet temp should be <135*F

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22
Q

What is the danger of a leak in the Essential Cooling Water Heat Exchanger?

A

Radioactive fluid will escape into the SP system and spread contamination.

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23
Q

What is the purpose of the Essential Cooling Water Surge Tanks?

A

Accommodate closed loop system expansion and contraction and ensure adequate NPSH for the EW pump.

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24
Q

What is the design of the Essential Cooling Water Surge Tanks?

A

Upstream of pump suction, 1000 gal, rated to 15 psig, connection for makeup water, overpressure/ underpressure, nitrogen gas addition, and level and pressure indications.

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25
What are the sources of makeup water for the Essential Cooling Water system?
Normal source-Demineralized Water Primary backup-Condensate Storage and Transfer system Secondary backup-Cooling Water HUT in Chemical Waste system Emergency-Fire Protection Header
26
What maintains the level of the Essential Cooling Water surge tank?
Level is maintained based on the state of the system. Level set point can be changed as needed. On a Lo-Lo 14" signal the makeup valve will auto close so we don't keep feeding a leak.
27
What does Nitrogen do in the Essential Cooling Water surge tank?
Prevents oxygen intrusion that could lead to corrosion.
28
What would cause the 'A' train cross-tie valve in the Essential Cooling Water system to close when tied to Nuclear Cooling water?
EW 'A' Surge Tank Lo Level 17" SIAS
29
What is the purpose of the Essential Cooling Water Chemical Addition Tanks?
Provide a place for the addition of corrosion inhibiting chemicals into the EW system.
30
What is the design of the Essential Cooling Water Chemical Addition Tanks?
One for each train, 11 gal, chemicals dissolved before adding to tank, tank's contents get flushed into the EW system.
31
What is the purpose of the Essential Cooling Water Radiation Monitors?
Provide non-safety related radiation monitoring to the EW system Alarm at a high EW radioactivity as a predictor of inter-system leakage.
32
What is the design of the Essential Cooling Water Radiation Monitors?
Continuously operating, alarms CR on hi radiation, flow through the monitor comes from pump discharge and returns to suction.
33
What is the purpose of the Essential Cooling Water to Nuclear Cooling Water cross-tie valves for the NC priority loads?
Allows the EW system to remove heat from the NC Priority Loads and reject that heat to the SP when NC is unavailable.
34
What is the design of the Essential Cooling Water to Nuclear Cooling Water cross-tie valves for the NC priority loads?
Before connecting EW to NC the NC non-priority heat load isolation valve must be closed to prevent transferring EW to the NC system. If you connect EW to NC EW is no longer operable for class Q.
35
What are NC Priority Loads?
Normal Chillers Nuclear Sample Coolers CEDM ACUs Reactor Coolant Pumps (Hp Coolers, Seal Coolers, Thrust Bearing coolers, LO coolers.)
36
What is the purpose of the Essential Cooling Water to NC cross-tie valves for the SFPHX?
Transfers decay heat from the SFP in the PC system to the SP under forced shutdown and accident conditions or when NC is unavailable.
37
What is the design of the Essential Cooling Water to NC cross-tie valves for the SFPHX?
NC supply and return isolation valves to the PC cooling HX must be closed first. Then you can open the valve to the EW to the PC cooling HX
38
How does a loss of the Essential Cooling Water system impact the operation of the plant?
EW is a tech spec required for safe shutdown, so it MUST BE OPERABLE. If we lose one train we will have to shut down. If we lose while shutdown we will not have a way to remove decay heat.
39
What is the Tech Spec 3.7.7 Essential Cooling Water Sytem?
Two EW trains shall be OPERABLE
40
What is the purpose of the purpose of the Essential Chilled Water system (EC)?
Supplies chilled water to the ESF ACUs and AHUs in the Control and Auxiliary Building when the normal chilled water system is unavailable or ESFAS signals.
41
What are the functions of the Essential Chilled Water System?
1.Ensure equipment operability following a DBE w Aux HVAC 2.Ensure equipment operability following a DBE w Control HVAC 3.With the HJ provide habitable environment in CR complex 4.With HJ&HA provide suitable environment during plant shutdown & startup.
42
What is the design of the Essential Chilled Water System?
Two 100% capacity, redundant safety chilled water trains. Each train has 100% chiller, 100% chilled water circ pump, expansion tank, chemical addition tank, and required piping.
43
What ESFAS signals will automatically start the Essential Chilled Water System?
CSAS SIAS CREFAS CRVIAS LOP AFAS
44
Which ACUs are in the flow path of the Essential Chilled Water system?
Control Room Essential D.C. Equip Room Essential ESF Swithgear Room Essential Electrical Penetration Room AHU HPSI pump room essential LPSI pump room essential CS pump room essential AF pump room essential EW pump room essential
45
What is the flow path of the Essential Chilled Water system?
Closed system, pump takes suction from expansion tank->cooler HX -> AHUs Only necessary AHUs are running. If temp of water gets to hi or lo other units may need to be turned on/off
46
What happens to liquid in the Chiller unit?
Changes into a vapor. The vapor is compressed and pumped to the condenser HX where it is cooled and condensed by EW flow through the tubes.
47
What powers the Essential Chilled Water system?
PB-powers the Essential Chillers PH-powers Aux power panels, Oil pumps, circ water pump, and motor space heaters PK-powers the EC Expansion Tank maeup water solenoid control valve NH-powers Essential Chiller pump out unit
48
What are the makeup water sources for the Essential Chilled Water system?
DW-normal supply CT-backup makeup supply FP-Emergency backup supply
49
What is the Essential Standby Power source for the Essential Chiller?
Emergency DG
50
What water system removes heat load from the Essential Chilled water system?
Essential Cooling Water EW
51
What is the purpose of the Essential Chilled Water Expansion Tank?
Accommodates system expansion and ensure adequate NPSH for EC pumps. Reservoir for leakage and location for makeup water.
52
What is the design of the Essential Chilled Water Expansion Tank?
Connected to the return header upstream of the EC circ water pump, 80 gal, connects to each makeup water source, over press, nitrogen gas addition, and instrumentation.
53
What is the Nitrogen as pressure in the Essential Chilled Water expansion tank?
>25 psig Minimum 10 psig with circ water pumps not in service to prevent flashing at the highest point in the system.
54
What is the purpose of the Essential Chilled Water Pumps?
Supply water to the EC system components under the required system resistance flow rate.
55
What is the design of the Essential Chilled Water Pumps?
One 100% capacity pump for each train, CP, single stage, 400 gpm, 20 hp motor (PH), controlled by CR When pump starts chiller will start after time delay Can also be controlled locally at the switch on the pump breaker.
56
What is the purpose of the Essential Chilled Water Chemical Addition Tank?
Provide a place to add corrosion inhibiting chemicals into the EC system.
57
What is the design of the Essential Chilled Water Cemical Addition Tank?
One in each train, 11 ga, normally isolated because of different piping in the EC system.
58
What is the purpose of the Essential Chillers?
Remove heat from the Chilled Water provided to the ACUs in the ESF Equipment rooms.
59
What is the design of the Essential Chillers?
One 100% capacity per train, 235 ton, removes heat from various parts of Aux and Control Buildings
60
What is the flow path through the Essential Chillers?
EC flows through the tubes of the cooler to transfer the heat it gained to the refrigerant. Refrigerant transfers the heat to the Essential Cooling Water EW flowing through the tubes of the condenser.
61
What is the purpose of the Chiller Control panels?
Local indication of the Chiller's status, alarms, and parameter indications.
62
What is the design of the Chiller Control Panels?
Two rows of red alarm lights One row of white indicating lights Amber light for oil heater energized Push button locally op Chillers Oil pump
63
What is the Chillers start sequence?
Start: signal > circ pump starts > timer starts (20 min restart relay, blocks addl restart attempt and 2 min ER time delay restart bypass > 23 sec chiller LO pump starts > 51 sec chiller compressor starts
64
What is the Chiller stop sequence?
Stop: signal > timer starts > chiller compressor and circ water pump both stop > 41 sec LO pump stops
65
What is the purpose of the Essential Chiller Refrigerant Head Pressure Control Valve?
RHPCV downstream of condensers to prevent condenser stacking.
66
What is the design of the Essential Chiller Refrigerant Head Pressure Control Valve?
RHPCV closes at condenser pressure below 14 psig and full open at condenser pressure greater than 23 psig.
67
What is the status of the bypass valves installed around the RHPCVs?
Normally locked closed. They are unlocked
68
What is the status of the bypass valves installed around the RHPCVs?
Normally locked closed. They are unlocked and opened when flowrate could be degraded during alt alignments. EW flow requires 720 gpm through condenser to provide sufficient cooling in a DBA in the hottest part of summer.
69
What are the automatic functions of the Essential Chillers?
When in neutral Essential Chillers and support equipment autostart on : SIAS, CSAS, LOP, CREFAS, CRVIAS, or AFAS
70
What is the autoload recycle?
When the cooler reaches a low temp of 38*F the chiller package shuts down this prevents the chiller from tripping at 34*F. The circ pump will cont. op, after the 20 min timer the cooler can restart once the temp has risen above 45*F. A white auto load recycle will be lit during this time
71
What is the normal op of the Essential Chilled Water System?
Normally in standby maybe started from CR, locally, or auto. Norm temp in 64*F out 44*F CR AHU controlled by a 3way temp valve If the temp gets too low other units will turn on to increase the temp in the system. Chemistry adds to minimize corrosion, dissolved then added to tank
72
How does a loss of Essential Chilled Wate System impact the operation of the plant?
If a train is lost then that trains ESF equipment is INOPERABLE by Tech Specs.
73
What is the tech spec 3.7.10 associated with the Essential Chilled Water system?
Two EC trains shall be OPERABLE Meaning pump, tank, HX, refrigeration unit, and instrumentation available.

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