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NLO Systems > EW- Essential Cooling Water > Flashcards

EW- Essential Cooling Water Flashcards

1
Q

What is the purpose of the Essential Cooling Water system?

A

Removes heat from all essential components required for normal and emergency shutdown of the plant and rejects the heat to the Spray Pond

Upon a loss of NC, can be lined up to provide cooling water for the Fuel Pool Cooling Heat exchangers, Reactor Coolant Pumps, CEDM normal ACUs, and nuclear sample coolers and normal chillers

Intermediate barrier between RC and Essential Spray Pond to reduce possibility of radioactive leakage to the environment

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2
Q

What is the normal source of makeup water to the EW? Backup sources?

A

Normal: Demineralized Water System (DW)

Backup: Chemical Waste System (CM) cooling water hold up tank

Safety related backup: Condensate Transfer and Storage System (CT)

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3
Q

What could be used as an emergency source of makeup water to the EW system?

A

Fire Protection system

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4
Q

If we were to drain the EWHXs, what system would I drain them to?

A

Oily Water System (OW)

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5
Q

What system provides power to the EW pumps?

A

PB

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6
Q

Where are the EW pumps located? What is the normal status of the suction and discharge valves?

A

70’ Aux Building

locked open

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7
Q

What is the rated flow for a typical EW pump?

A

16,650 gpm at 138 ft TDH

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8
Q

What signals would automatically start the EW pumps?

A

LOP (20 seconds after EDG output breaker closes)

CSAS

SIAS

CREFAS

CRVIAS

AFAS 1 and 2

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9
Q

What electrical protection is available to the EW pump motors?

A

Overcurrent and ground fault protection trips that actuate an 86 lockout relay

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10
Q

What else starts when the EW pump starts?

A

EW pump room ACU (cooled by Essential Chilled Water)

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11
Q

What is the purpose of the EW surge tanks? What is the capacity and pressure of the EW surge tanks?

A

Allow for makeup water to be added to the system

Accommodate for changes in system volume due to temperature changes

Provide a means of detecting leakage into or out of the system

Provide NPSH to the EW pumps

1000 gallons at 15 psi

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12
Q

Why do we pressurize the EW Surge tanks with nitrogen?

A

To prevent oxygen from getting into the system that could lead to corrosion

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13
Q

When Train “A” EW is cross-connected to NC, what two conditions would close the Train “A” EW to NC cross-tie valves?

A

EW “A” Surge Tank Lo Level (17”)

SIAS

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14
Q

At what level in the EW Surge tank would the normal makeup valve automatically close to prevent feeding a leak?

A

14”

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15
Q

Using the EW chemical addition tanks, we add chemicals to maintain pH and nitrite concentrations at what values?

A

pH between 8.0 and 10.5

nitrite between 400 and 800 ppm

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16
Q

What is the capacity of the EW chemical addition tanks? Where are they located?

A

11 gallons

next to respective EW pump

17
Q

Why do we have EW radiation monitors?

Where are they located?

A

Detect RC or reactor auxiliary system leak into the EW system (measure gross gamma activity)

next to respective EW pump

18
Q

What system provides power to the Train ‘A’ EW to NC Cross-tie valves?

A

PH

19
Q

What flow requirement is associated with the EW system?

A

720 gpm through the essential chiller condensers is necessary to provide sufficient cooling capacity to accommodate a design basis accident in the hottest part of the summer when the EW water temp is 132F

20
Q

What happens on loss of EW system?

A

If one train becomes inoperable, a shutdown will have to be performed after a period of time

When shutdown, you will have a loss of cooling to SDC heat exchanger, which will affect decay heat removal

21
Q

What are the NC system priority loads?

A

RCP Seal Coolers, Thrust bearing coolers, and motor coolers

CEDM Normal ACU

Nuclear Sample coolers

One of the normal chillers

22
Q

What is the EW surge tanks High Level control point?

A

30”

23
Q

What is the EW surge tanks low level control point? (EXPLANATION QUESTION)

A

25”

24
Q

How is EW affected upon a loss of PK?

A

Loss of control power to EW system surge tank solenoid valves = fail closed. (Operator will have to bypass the solenoid valves and manually makeup the surge tanks)

Loss of remote operation of Class 4160 kV breakers and breaker indications

25
Q

What system powers the EW system instrumentation?

A

PN

26
Q

What flows does the EW cooling water hold up tank receive?

A

EW surge tank overflow and EWHX floor drains

27
Q

How does the EW system interface with the EC system?

A

EW removes heat from EC chillers

EC sends chilled water through the EW pump room ACU

28
Q

When does the EW pump room ACU start?

A

when the pump starts

29
Q

What happens when the EW system receives signals from the ESFAS?

A

EW-NC cross-tie valves auto close on SIAS

EW pumps start on LOP and load sequence

30
Q

Where are the Radiation monitors in the EW system?

A

bypass loop around each EW pump

31
Q

What is the design outlet temperature of the EWHX?

A

<135*F

32
Q

What over pressure protection is provided for the shell side of the EWHX? Why is the tube side SP pressure higher than the EW shell side?

A

relief valves

to prevent radioactive material leaking to the environment

33
Q

Where are the EWHXs located?

A

100’ aux building west side

34
Q

Where are the EW surge tanks located?

A

120’ aux building

35
Q

What must be done prior to opening the EW to NC cross tie valves? Why?

A

close NC non-priority heat load isolation valve so EW water doesn’t get transferred to NC system

36
Q

Where are the EW to NC priority load cross tie valves located?

A

70’ aux building next to SDCHX

37
Q

When would EW cool the SFP HXs?

A

When NC is not available

38
Q

When aligning the EW system to cool the SFP HXs, what must be done prior to opening the EW valves?

A

closing the NC supply and return isolation valves for the HX

39
Q

What is the tech spec related to the EW system?

A

two EW trains must be OPERABLE

NLO Systems (66 decks)

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