PW- Plant Cooling Water

Question 1

[PW]

Purpose? (4)

Answer 1

1 - Uses [CW] to remove heat from [TC], [NC], and [AR], rejects heat back to [CW].

2 - Water to the [CW] screen wash area

3 - Water to [CI] acid injection static mixers

4 - Fill [CD] water boxes and [CW] during startup or after [CD] maintenance

Question 2

[PW]

What happens when normal return flow [CW] canal is not available?

Answer 2

-alternate return path to #2 cooling tower

Question 3

[PW]

[PW] Pumps
Capacity?
Power?

Answer 3

-2 100% parallel
-[NB]

Question 4

[PW]

Pump Motor Space Heater Power?

Answer 4

[NH]

Question 5

[PW]

[PW] Pumps
Lubrication?
Cooling?
Pump and motor shaft connection?

Answer 5

-Oil Lubed
-Air cooled
-Flexible flange coupling

Question 6

[PW]

[PW] Pumps - Auto Feature?

Answer 6

Low D/P (40 psig) will auto start Standby pump

Alarm in the Control Room

‘A’ – NBN-S01 ‘B’ – NBN-S02

Question 7

[PW]

[PW] Pumps
How does CR know the standby [PW] pump has auto started?

Answer 7

-Amber Light is lit

Question 8

[PW]

[PW] Pumps
What is normal discharge header pressure?

Answer 8

~45-48

Question 9

[PW]

[PW] Pump
When do Trash Screens require a wash down?

Answer 9

-High Differential Level between intake Canal and Pump Suction Bay
-12 inches

Question 10

[PW]

[PW] Outlet Valves
If normal position of the PW outlet valves on the standby HXs is closed. What is the normal throttled position for the PW outlet isolation valves for both in-service TC and NC HXs?

Answer 10

33% (30*)

Question 11

[PW]

[NC] Hx
What side of the Hx is [PW] on?
Why isn’t this an issue?

Answer 11

-Tube side

• [PW] is at a higher pressure than [NC].
• Meaning [PW] would still leak to [NC] in the case of a tube break.

Question 12

[PW]

[PW] Pump Suction Bays
How do we isolate and drain for maintenance?

Answer 12

-Stop-gates

inserted just behind the screens

Question 13

[PW]

Loss of [PW] on plant?

Answer 13

-High temperature in:
[NC]
[TC]
[AR]

-If not corrected, a manual trip required

-Numerous alarms would annunciate in the CR within seconds of the loss due to the loss of TC on Main Turbine

Question 14

[PW]

How does [PW] system affect reactor power?

Answer 14

NC system would no longer have a heatsink. NC temp. rises, Letdown temp. rises and affects the Purification ion exchangers.

higher temp = releases boron into charging water and RCS, reduces reactor power

Question 15

[PW] T-Mod

When is [PW] T-Mod used?

Answer 15

-Outages
-Provide temporary cooling to [NC] Hx “B” when [PW] is not avaliable.

Question 16

[PW] T-Mod

How do you add more loads to the PW T-Mod than intended for?

Answer 16

With CR discretion and/or Work Control

Question 17

[PW] T-Mod

Flow path of PW T-mod?

Answer 17

• 2 (temporary) circulating pumps take suction from a (portable) retention tank and pump the water through NC heat exchanger “B”. The water flow is throttled by flow orifices and the cooling tower inlet valves to ~2400 gpm per cooling tower. The water enters the two portable cooling towers for heat removal via evaporative cooling and flows into the portable retention tank to complete the circuit

Question 18

[PW] T-Mod

Portable Retention Tank
Capacity?

Answer 18

Normal operating level is ~4000 gallons, but when the system is filled prior to startup or is shutdown and the system allowed to drain back there will be about 5200 gallons in the tank

Question 19

[PW] T-Mod

[PW] T-Mod Circulating Pumps
Capacity?
Powers?

Answer 19

3000 gpm/each

[NH]

Question 20

[PW] T-Mod

Primary M/U water source?

Answer 20

Essential [SP] “A”
(thru temporary M/U pumps)

Question 21

[PW] T-Mod

Secondary M/U water source?

Answer 21

[DS]
return from IA and Service Air compressor when they are being operated on temporary cooling water from DS

Question 22

[PW] T-Mod

[PW] T-Mod is designed to cool [NC] during outage when the heat load consists of what 5 sources?

Answer 22

1 [SP] Hx

2 Normal Chillers (50% load)

BAC @ 40% load

[LR] Evaporator @ 50% load

[AS] Vent Condenser

Question 23

[PW] T-Mod

Power for [PW] T-Mod equipment?

Answer 23

Unit 1

• Construction Substation N through portable Mobile Substation R to Temporary Panel A, then to equipment
• Construction panel A4 or a portable generator through a portable Manual bus Transfer Switch to Temporary Panel A, then to equipment

Unit 2
-Construction Substation 100 through Portable Mobile Substation R to temporary panel A then to the equipment

Unit 3
-Construction Substation 200 through portable Mobile Substation R to Temporary Panel A, then to the equipment

Question 24

[PW] T-Mod

Blowdown flow rate back to [SP]?

Answer 24

50 – 120 gpm

Question 25

[PW] T-Mod

How can I warm up NC?

Answer 25

Bypass around the HX

If more warming is required and the bypass is full open, outlet valve may be throttled closed

Question 26

[PW]

Is swapping [NC] and [TC] Hx make-before-break process?

Answer 26

yes

Question 27

[PW]

What procedure is used for filling of condenser with [PW]?

Answer 27

40OP-9PW01

Question 28

[PW]

What is an AO job while the PW system is filling the condenser?

Answer 28

manually operating the CW auto vent valves

Question 29

[PW]

Where are the Circulating water fill valves located?

Answer 29

in pits in the north yard of each unit

Question 30

[PW]

How does the loss of PW affect the CI (Chlorine Injection System)?

Answer 30

it would require acid to be added to the canal by an alternate method

(normally, gravity flow from acid storage tanks to an eductor with PW water flowing through it)

Question 31

[PW] T-Mod

Flow orifice plates purpose in each [NC] Hx outlet pipe to PW T-Mod cooling towers?

Answer 31

maintain a minimum back pressure on the HX to ensure it stays full of water during operation

Question 32

[PW] T-Mod

How many fans are on each [PW] T-Mod cooling tower?
Powered from?

Answer 32

8

[NH]

Question 33

[PW] T-Mod 1.6

Normal Operation
What is the normal operating line up of [PW] T-Mod?

Answer 33

both cooling towers
both circulating pumps
both make up pumps
16 fans operating (ALL)

Question 34

[PW] T-Mod

[PW] T-Mod
Concerning the PW T-Mod, the cooling tower inlet valves are throttled to equalize flow to the towers and maintain outlet pressure from the NCHXs. What is the NCHX outlet pressure normally?

Answer 34

40-45 psi