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Systems > Nuclear Cooling Water > Flashcards

Nuclear Cooling Water Flashcards

1
Q

What’s the purpose of the NC Pumps ?

A

Circulates water for removal of heat from loads for transfer to PW system

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2
Q

Where are the NC pumps powered from ?

A

Powered from 4.16kv NBN-S01 & NBN-S02

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3
Q

What’s the GPM & discharge pressure for the NC pump ?

A

Pumps approx. 17500gpm at discharge pressure of 100-110psig

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4
Q

What kind of seals do the NC pumps use? Do you expect leakage from NC pump

A

They used mechanical Seals so shouldn’t expect any leakage from it

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5
Q

Where are the NC pumps normally started from? Where else can they be started ??

A

-They’re normally started from control room
-Can also be started locally at the breaker

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6
Q

How many NC pumps are usually running ?

A

-Normally one NC pump is running to supply system
-Other pump is in standby

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7
Q

What happens if operating NC Pump discharge pressure drops to it setpoint of 79psig ?

A

Standby pump will start

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8
Q

What happens if NC pump trips on electrical fault or physical degradation?

A

Local conditions may warrant quick actions by control room to prevent further equipment damage

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9
Q

What must be done for any auto start of a NC pump ?

A

Should be investigated locally and reported back to control room

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10
Q

What’s the purpose of the NC HEX ?

A

Used to transfer heat from NC system to PW system to be dissipated to atmosphere at CW Cooling Towers

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11
Q

What is installed on NC HEX for protection of over pressurizations ?

A

There is relief valves on shell & tube side to prevent over pressurization

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12
Q

Why is the PW pressure higher than NC system while going through NC HEX ?

A

-NC could have potential contamination from RC or Radwaste systems
-PW will leak into NC if a leak occurred inside NC HEX
-Used to prevent PW contamination and outside environment

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13
Q

How many NC HEX are normally in service ? What is the PW outlet valve normally throttled to on the inservice HEX ?

A

-Normally ONE HEX in service
-PW outlet valve throttled to 33% open for in service HEX

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14
Q

How is the standby NC HEX kept in standby ?

A

Both NC & PW outlet valves are closed with flow secured through it

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15
Q

How is NC temp controlled to maintain between 75-105F ?

A

Controlled manually by:
-Throttling HEX NC outlet valve
-Throttling bypass valve to maintain flow through & around HEXs

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16
Q

To maintain adequate system flow through NC HEX, what MUST be the position of the one valves when adjusting temperature of NC supply ?

A

-Either NC Outlet valve fully open or Bypass valve fully open
-Once one those valves is fully open you can use other valve to adjust temperature

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17
Q

In the summer instead of adjusting the NC HEX outlet valve or bypass valve, what other valve can you use to adjusted NC temperature ?

A

-PW outlet valve can be adjusted to lower NC temp

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18
Q

During summer why would you have to adjust PW outlet valve ?

A

Would have to be down when NC outlet valve is Fully Open & Bypass valve is Fully Closed & NC temperature is still high

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19
Q

What does the control room monitor as the primary means for adjusting NC temperature ?

A

Monitors flow through Letdown HEX

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20
Q

What is the Max. NC Flow through the Letdown HEX ?

A

-Max NC flow is 1500gpm

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21
Q

What happens to flow through Letdown HEX, when NC temperatures rise ?

A

Flow the Letdown HEX will rise to maintain Letdown Temp

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22
Q

What happens if Letdown HEX flow limit is reached & NC temperature continues to rise ?

A

Control room will direct AO to adjust NC temp generally maintained low in band

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23
Q

What is the purpose of NC Surge Tank ?

A

-Accommodate for volume changes in system due to temp changes
-Provide NPSH for NC Pumps
-Provides detection of leakage into or out of NC system
- Convenient place to add makeup water

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24
Q

What protection is in place for the surge tank to protect against a vacuum or over pressurization ?

A

-Pressure relief for over pressurization
-Vacuum breaker to prevent vacuum

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25
Q

What is the normal makeup source to the NC Surge Tank ? How is Demin. Water makeup controlled ?

A

-Demineralized water is used for makeup water
-Controlled by control valve in response to signals from level controller

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26
Q

Where is the backup makeup water to NC Surge Tank from ? How backup makeup water controlled ?

A

Backup makeup water is available from Cooling Water Holdup Tank by manual operation

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27
Q

What pressure is the Nitrogen cover gas at in the Surge Tank ?

A

Pressurized at 5psig to prevent oxygen intrusion

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28
Q

What could happen to surge tank if a RCP High Pressure Seal Cooler tube rupture happens ?

A

Could over pressure the NC system and eventually have a uncontrolled release through NC Surge Tank

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29
Q

Who must give permission to have chemical additions performed on NC system ?

A

-Must have approved Chemistry Control Instruction on file in control room
-SM/CRS gives permission

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30
Q

What does the Chemistry Control Instruction provide ?

A

Lists the chemical & quantity that’ll be added

31
Q

Who is responsible to deliver the chemicals? Who is required to verify the chemicals ?

A

-Chemistry must deliver chemicals
-AO has to verify chemicals

32
Q

What is the normal conditions of the Chemical Addition Tank ? What condition is it in during winter months ?

A

-Normal condition is isolated & depressurized
-Cold Weather Protection will have flow aligned through tank to prevent freezing

33
Q

What does the Radiation monitor provide for NC system ?

A

Continuously monitors NC system for in-leakage from contaminated systems that it serves

34
Q

Where does the NC RU monitor provide alarms & trending capabilities? What does a activity alarm indicate ?

A

-Does this via computer consoles in Effluent office & Control Room
-Indicates potential contaminated leakage

35
Q

What drives flow through the NC RU-6 monitor?

A

-DP by NC pump, from the discharge to the NC HEX Inlet

36
Q

What is the purpose of the Letdown HEX Temp Control Valve ?
(NCN-TV-223)

A

Used to automatically control NC flow through the Letdown HEX to maintain letdown temperature

37
Q

What NCN-TV-223 normally controlled by?

A

Normally controlled by CHN-TIC-223, at the setpoint by control room

38
Q

In event of inability of NCN-TV-223 being able to control letdown temp due to valve failure or loss of instrument air, what else can be used to control letdown temp ?

A

-Temperature can be controlled manually via a bypass around control valve

39
Q

What must operators be aware if you have to manually control Letdown Temp ?

A

-To much NC flow makes letdown to cold causing resin to absorb more boron which causes positive reactivity
-Little NC flow makes letdown temp rise, resin gives off boron causing negative reactivity
-Also little NC flow will cause Ion Exchangers to be bypassed & letdown will be isolated

40
Q

What’re NC priority heat loads ?

A

-Normal Chillers
-CEDM Coolers
-RCPs
-Nuclear Sample Coolers

41
Q

What’re the Non-Priority Heat Loads ?

A

-SFP HEX
-Letdown HEX
-Radwaste Evap.
-BAC
-Non-Nuclear sample Coolers
-A/B Waste Gas Compressors
- Letdown HEX
-Gas Stripper
-Aux. Steam Vent Cond.
-RU-7 cooling coil

42
Q

What is the EW to NC Crosstie Valve used for ?

A

-Used when NC is unavailable for its Priority Head Loads during normal operation or Loss Of Power

43
Q

Which train of EW can be interconnected remotely to NC Priority Heat Loads ?

A

-‘A’ train can be interconnected to NC Priority Head Loads Remotely by MOV UV-145 & UV-65
-‘B’ train can be interconnected manually to NC Priority Heat Loads

44
Q

Prior to opening the EW to NC Crosstie Valves what must be isolated ?

A

NC Non-Priority Heat Loads must be isolated to prevent transferring EW into the NC system

45
Q

When the EW to NC Crosstie Valves are open, what happens during a SIAS or a Train ‘A’ EW Low Surge Tank ?

A

EW to NC CrossTie valves will automatically go closed

46
Q

Is the EW system considered operable when the EW to NC CrossTie Valves are in service ?

A

NO, the EW system will be inoperable until the crosstie valves close

47
Q

What is the purpose for the SFP EW to NC Crosstie valves used for?

A

-EW transfers decay heat loads from SFP to the Spray Pond under forced forced shutdown & accident conditions OR when NC is unavailable

48
Q

What must be isolated to allow SFP EW to NC Crosstie Valves to be opened ?

A

-NC SFP HEX Inlet & Outlet Valve must be isolated

49
Q

Once SFP HEX NC Inlet/Outlet valves are isolated, what can you do ?

A

The normally locked closed EW crosstie SFP HEX valves, can be unlocked and opened

50
Q

When do the NC supply & return Containment Isolation Valves automatically close ?

A

They will automatically close on a CSAS

51
Q

Why is there a Pressure Relief Valve(NCE-PSV-617) on the return line coming out of containment ?

A

-Used to prevent over-pressurization during a LOCA
-Water trapped in penetration line can expand during LOCA due to the water flashing
-Might rupture piping & cause loss of containment isolation

52
Q

Why is there no relief protection on the supply line penetration going inside containment ?

A

There a check valve which would pass flow & won’t allow accumulation in piping

53
Q

What’re the Pressure Relief Valves NCE-PSV-614 & NCE-PSV-615 used for ?

A

Used to protect piping inside containment against over pressurization & damage in event of leakage of RCP Seal Coolers into NC in conjunction with NC containment Isolation Valves closing

54
Q

What’re the setpoints for pressure relief valves NCE-PSV-614 & NCE-PSV-615?

A

Setpoint is 135psig

55
Q

What happens if you isolate NC containment return lines, while NC supply line is still open ?

A

It can cause a pressure surge in the NC system that will lift the reliefs

56
Q

How do you prevent lifting of relief when placing containment section system in service ?

A

NC return isolation valves should be opened PRIOR to opening supply line

57
Q

When removing containment NC system from service what containment valves do you close first ?

A

-Supply valve must be closed before either of the returns

58
Q

When is NC system normally in service ? What is NC required for ?

A

-In service during all modes of plant operation
-Required for normal plant operation & normal shutdown
-Not required for emergency situation safe shutdown

59
Q

What is the normal NC Pump discharge pressure ? When will standby pump start ?

A

-Discharge pressure is 100-110psig
-Standby Pumps will start if header pressure drops to 79psig

60
Q

What NC temp maintained between ?

A

Maintained between 75-105F, but as low in the band as possible

61
Q

How is the NC flow through the Normal Chillers controlled?

A

Automatically controlled by motor controlled valves which open in start sequence of chiller

62
Q

During outages when PW system is secured, what is NC cooled by?

A

-Cooled by the PW T-Mod that’s tied into ‘B’ NC HEX PW supply & return
-T-Mod provides cooling NC from ‘A’ Spray Pond
-Provides cooling for a portion of normal loads

63
Q

What does the PW T-Mod consist of ?

A

Consist of:
-portable water basin
-Pumps
-Piping
-Cooling Towers

64
Q

What does the PW Temporary Cooling system was designed to cool NC system heat loads consist of what ?

A

-One SFP HEX
-TWO normal Chillers at 50% load
-BAC at 40% load
-LRS Evap at 50% load
-Aux. Steam Vent Cond.

65
Q

What happens on a loss of NC to the RCPs ?

A

-With RCP Seal Injection in service cooling flow must be restored within 10 minutes
-If not restored in 10 mins reactor must trip & RCPs secured

66
Q

When EW is cooling NC priority Heat Loads how would you clear RCP low flow alarms ?

A

You would have to unlock & throttle SDCHX EW outlet valve to force flow to RCPs

67
Q

What Tech Spec are affected when Cross Tying EW to NC Priority Heat Loads ?

A

-Associated EW Train is inoperable
-Associated EC Train is inoperable

68
Q

What Tech Spec are affected when cross tying EW to SFP HEX ?

A

-Associated EW Train will initially be inoperable
-Flow balance can restore operability of the EW Train
-Manual override of RHPCV will cause Essential Chiller to be inoperable during Flow Balance
-Be sure other Train is operable BEFORE manually overriding RHPCV

69
Q

What happens to normal chillers if NC is lost ?

A

Normal Chillers will trip; If EW is supplying normal chillers than ONE chiller can be restarted

70
Q

What chiller will continue running on a LOP ?

A

A chiller will continue running because it’s powered from PBA-S03

71
Q

What happens to NC pumps if you lose NH ?

A

Will lose NC Pumo Motor space Heater which wouldn’t meet requirements to start standby NC Pump

72
Q

What happens to NC system on a loss of NK ?

A

Would lose power to NC Surge Tank makeup solenoid valve failing closed which would causes loss of automatic makeup

73
Q

What’re the Tech Specs related to the NC Containment Isolation Valves ?

A

-Each containment isolation valve must be operable in modes 1-4
-close in required time of 60seconds

Systems (62 decks)

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