PW- Plant Cooling Water Flashcards
[PW]
Purpose? (4)
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
[PW]
What happens when normal return flow [CW] canal is not available?
-alternate return path to #2 cooling tower
[PW]
[PW] Pumps
Capacity?
Power?
-2 100% parallel
-[NB]
[PW]
Pump Motor Space Heater Power?
[NH]
[PW]
[PW] Pumps
Lubrication?
Cooling?
Pump and motor shaft connection?
-Oil Lubed
-Air cooled
-Flexible flange coupling
[PW]
[PW] Pumps - Auto Feature?
Low D/P (40 psig) will auto start Standby pump
Alarm in the Control Room
‘A’ – NBN-S01 ‘B’ – NBN-S02
[PW]
[PW] Pumps
How does CR know the standby [PW] pump has auto started?
-Amber Light is lit
[PW]
[PW] Pumps
What is normal discharge header pressure?
~45-48
[PW]
[PW] Pump
When do Trash Screens require a wash down?
-High Differential Level between intake Canal and Pump Suction Bay
-12 inches
[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?
33% (30*)
[PW]
[NC] Hx
What side of the Hx is [PW] on?
Why isn’t this an issue?
-Tube side
- [PW] is at a higher pressure than [NC].
- Meaning [PW] would still leak to [NC] in the case of a tube break.
[PW]
[PW] Pump Suction Bays
How do we isolate and drain for maintenance?
-Stop-gates
inserted just behind the screens
[PW]
Loss of [PW] on plant?
-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
[PW]
How does [PW] system affect reactor power?
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
[PW] T-Mod
When is [PW] T-Mod used?
-Outages
-Provide temporary cooling to [NC] Hx “B” when [PW] is not avaliable.
[PW] T-Mod
How do you add more loads to the PW T-Mod than intended for?
With CR discretion and/or Work Control
[PW] T-Mod
Flow path of PW T-mod?
- 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
[PW] T-Mod
Portable Retention Tank
Capacity?
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
[PW] T-Mod
[PW] T-Mod Circulating Pumps
Capacity?
Powers?
3000 gpm/each
[NH]
[PW] T-Mod
Primary M/U water source?
Essential [SP] “A”
(thru temporary M/U pumps)
[PW] T-Mod
Secondary M/U water source?
[DS]
return from IA and Service Air compressor when they are being operated on temporary cooling water from DS
[PW] T-Mod
[PW] T-Mod is designed to cool [NC] during outage when the heat load consists of what 5 sources?
1 [SP] Hx
2 Normal Chillers (50% load)
BAC @ 40% load
[LR] Evaporator @ 50% load
[AS] Vent Condenser
[PW] T-Mod
Power for [PW] T-Mod equipment?
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
[PW] T-Mod
Blowdown flow rate back to [SP]?
50 – 120 gpm
[PW] T-Mod
How can I warm up NC?
Bypass around the HX
If more warming is required and the bypass is full open, outlet valve may be throttled closed
[PW]
Is swapping [NC] and [TC] Hx make-before-break process?
yes
[PW]
What procedure is used for filling of condenser with [PW]?
40OP-9PW01
[PW]
What is an AO job while the PW system is filling the condenser?
manually operating the CW auto vent valves
[PW]
Where are the Circulating water fill valves located?
in pits in the north yard of each unit
[PW]
How does the loss of PW affect the CI (Chlorine Injection System)?
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)
[PW] T-Mod
Flow orifice plates purpose in each [NC] Hx outlet pipe to PW T-Mod cooling towers?
maintain a minimum back pressure on the HX to ensure it stays full of water during operation
[PW] T-Mod
How many fans are on each [PW] T-Mod cooling tower?
Powered from?
8
[NH]
[PW] T-Mod 1.6
Normal Operation
What is the normal operating line up of [PW] T-Mod?
both cooling towers
both circulating pumps
both make up pumps
16 fans operating (ALL)
[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?
40-45 psi