NC- Nuclear Cooling

Question 1

[NC]

Pump capacities
How many are normally in operation?

Answer 1

-2 pumps in parallel
-100%
-1/2

100-110 psig (17,500 gal/min)

Question 2

[NC]

[NC] Pump power supply?

Answer 2

[NB]

‘A’ – NBN-S01 ‘‘B’ – NBN-S02

Question 3

[NC]

What auto starts standby [NC] pump?

Answer 3

Pump discharge header pressure
79 psig

Question 4

[NC]

How would the Control Room know if [NC] standby pump auto started?

Answer 4

Amber Light (Lit) in CR

Question 5

[NC]

Which side does [PW] flow through on [NC] Hx (Tube or Shell?)

Answer 5

Tube Side

Question 6

[NC]

To shift to standby Hx, what actions must be performed?

Answer 6

Vent on-coming Hx on both shell and tube side to ensure a filled condition.

Question 7

[NC]

How do we manually adjust [NC] temperature?
What temperature band?

Answer 7

Temp Up - Open Flow Bypass Valve (bypassing Hx)

Temp Down - Close Flow Bypass Valve (more flow to Hx)

75-105*F

Question 8

[NC]

Which system of the [NC] Hx, is at a higher pressure?

Answer 8

[PW]
to prevent potentially contaminated nuclear cooling water leakage into the PW system and environment

Question 9

[NC]

[NC] Surge tank purpose? (4)

Answer 9

-Absorb fluxtuations in system due to temperature changes

-NPSH for [NC] pumps

-detecting leakage

-Location for adding makeup water

Question 10

[NC]

Surge Tank location?
Capacity?

Answer 10

AB Roof (NE)

1000 gal

Question 11

[NC]

Makeup water to [NC]?
What is it inserted into?

Answer 11

[DW] Demineralized Water
Surge Tank

Question 12

[NC]

Backup makeup water source to [NC] ?
Where are the valves to align this back up make up source?

Answer 12

[CM] Chemical Waste System

100’ aux building, south wall

Question 13

[NC]

Purpose of nitrogen in the Surge tank?

Answer 13

Cover gas -oxygen exclusion for corrosion

5 psig

Question 14

[NC]

How are chemicals added to the system with th Chem Add Tank?

Answer 14

D/P with [NC] pump flush

Question 15

[NC]

The NC Chem Add Tank is normally isolated. Besides adding chemicals, when would we align flow through it and why?

Answer 15

When Cold Weather Protection is in effect to prevent freeze damage

Question 16

[NC]

What does RU-6 monitor?
Location?

Answer 16

[NC] in-leakage from the contaminated systems it cools
Turbine Building North Yard

Next to the [NC] pumps

Question 17

[NC]

Letdown Hx TCV purpose?

Answer 17

Control [NC] flow thru Hx to auto regulate LDHx outlet temp setpoint by CR

NCN-TV-223 - (usually 120F) - AB 110’ above LDHx

Question 18

[NC]

Why, as AO’s, should we worry about the flow of NC through the LDHX? What is the maximum NC flow rate through the letdown HXs?

Answer 18

Because it controls Letdown temperature and could ultimately affect reactivity

1500gpm

Question 19

[NC] 10

What are the 8 Priority heat loads?

Answer 19

Normal Chillers

Nuclear Sample Coolers

CEDM Normal ACUs

[RC] RCP
Seal coolers
HP coolers
Thrust Bearing Coolers
Motor Air coolers
Lube Oil Coolers

Question 20

[NC]

What is the purpose of the relief valve NCE-PSV-617?

Answer 20

Protect the containment NC return penetration from exceeding its design pressure rating after a LOCA

It protects the system between the inside and outside containment isolation valves

Question 21

[NC]

Why are we worried about overpressure in the penetration piping for the NC system between the inside and outside isolation valves?

Answer 21

The water trapped in the penetration piping could be heated by the conditions in the containment and the resulting expansion might rupture the piping and cause a loss of containment isolation

Question 22

[NC]

Why do we not have relief protection on the supply penetration piping for the NC system?

Answer 22

Because the inside containment valve is a check valve which would pass flow and therefore not allow any pressure accumulation in the piping

Question 23

[NC]

What is the purpose of relief valves protecting NC inside containment?

Answer 23

Protect the NC system piping inside the containment against over pressurization and potential damage in the event of leakage from a RCP seal cooler into the NC system in conjunction with a closure of the NC containment isolation valves

Question 24

[NC]

The setpoint for the NC inside containment relief valves is 135 psig. Why is that significant?

Answer 24

Low enough to require a special operating sequence for the NC motor operated containment isolation valves because isolation of the containment return path with the supply path still aligned can cause a pressure surge in the NC system that will lift the reliefs

Question 25

# [NC] What types of valves are on the supply and discharge lines through containment for NC? What would cause the NC supply and return containment isolation valves to automatically shut?

Answer 25

supply line- motor operated outside, check valve inside return line- motor operated valves inside and outside containment CSAS

Question 26

# [NC] What system provides a backup source of cooling water for NC system loads?

Answer 26

EW

Question 27

# [NC] If NC is lost to the RCPs, how long would I have to restore it?

Answer 27

10 minutes 3 minutes if its lost to more than one RCP

Question 28

# [NC] What temperature is NC maintained at and what is preferred?

Answer 28

Between 75F and 105F, but less than 85F is preferred

Question 29

# [NC] The PW T-mod was designed to cool NC when the heat load consists of what components?

Answer 29

One Spent Fuel Pool heat exchanger Two Normal Chillers at 50% load BAC at 40% load LRS Evaporator at 50% load AS Vent Condenser

Question 30

# [NC] What is the purpose of the NC system?

Answer 30

provide cooling during all modes of operation to the priority and non-priority loads intermediate buffer volume between plant cooling water and potentially contaminated flow streams to reduce the probability of releasing radioactivity to the environment.

Question 31

# [NC] Why is the NC constantly monitored by a radiation monitor around the NC pumps?

Answer 31

due to the potential for leakage into the NC system from other radioactive systems

Question 32

# [NC] What protections does the NC surge tank have?

Answer 32

hi-lo level/pressure, level sight glass and controller, local temperature indicator, pressure relief and a vacuum breaker

Question 33

# [NC] What potential impacts on the plant does manually controlling letdown temperature?

Answer 33

too much NC flow, letdown too cool, boron absorbed, positive reactivity too little NC flow, letdown too hot, boron released, negative reactivity

Question 34

# [NC] What are the NC "non-priority loads"?

Answer 34

``` letdown hx radwaste evaporator boric acid concentrator waste gas compressors non-nuclear sample coolers aux. steam vent condenser gas stripper aux. steam rad. monitor (ru-7) cooling coil spent fuel pool cooling hx ```

Question 35

# [NC] What must be done prior to opening the EW-NC cross-tie valves?

Answer 35

close the NC non-priority load isolation valve

Question 36

Where is the NC non-priority load isolation valve located?

Answer 36

77' aux. building unassigned room

Question 37

Where are the EW cross-tie to NC valves located?

Answer 37

70' aux. building, shutdown cooling hx room

Question 38

Are the isolation valves to transfer EW to NC for the fuel pool hx make-before-break?

Answer 38

yes

Question 39

# [NC] In the NC system, what does NH power?

Answer 39

NC pump motor space heaters CEDM ACU and normal chiller NC outlet valves

Question 40

# [NC] In the NC system, what does NK power?

Answer 40

NC surge tank make up solenoid valve

Question 41

# [NC] In the NC system, what does PH power?

Answer 41

NC containment isolation valves

Question 42

# [NC] What is the back up cooling water system for the shutdown cooling HXs?

Answer 42

NC

Question 43

# [NC] What is the back-up make-up system for the NC system?

Answer 43

CM

Question 44

# [NC] Which [NC] Hx is the [PW] T-Mod usually hooked to?

Answer 44

B

Question 45

# [NC] What status does cross-tying the EW to NC loads put the EW equipment in?

Answer 45

INOPERABLE

Question 46

# [NC] What happens when NC is lost to the WC system?

Answer 46

normal chillers trip

Question 47

# [NC] Are the NC supply and return line motor operated valves fail close or as is?

Answer 47

fail as is

Question 48

# [NC] What is the tech spec related to the NC system containment isolation valves?

Answer 48

must be able to close in 60 seconds