PW- Plant Cooling Water Flashcards
What are the functions of the PW system?
Remove heat from the TC, NC, and AR systems and reject that heat to CW
Fill condenser water boxes and CW system during startup or after condenser maintenance
Provide water to the CW screen wash area hose connections
Provide water to the chlorine injection system acid injection static mixers
What is the capacity of the PW pumps? Where do they receive power from? What powers the motor space heaters?
100% each (29,000 gpm)
NB
NH
How are the PW pumps lubricated and cooled? How are the pump and motor shafts connected?
Oil lubricate and air cooled
flexible flange coupling
What is the automatic feature associated with the PW pumps?
Standby pump will automatically start when a low pressure condition (~40 psig) is sensed on the discharge of the operating pump
alarm in the control room
How would the Control Room know that the standby PW pump has auto started?
Amber light lit for the associated pump
What are the PW pump power supplies?
‘A’ – NBN-S01
‘B’ – NBN-S02
How would I know that the PW pump trash screens require a wash down?
High differential level (12 inches) observed between the intake canal and the pump suction bay
What impact does a loss of PW have on the plant?
High temperature condition within NC, TC, and AR. If not corrected, a manual trip is required
The Main Turbine immediately feels the loss due to the loss of TC, so numerous alarms would annunciate in the Control Room within seconds of the loss
When is the PW T-mod used?
During outages to provide temporary cooling to Nuclear Cooling Water Heat Exchanger “B” when the Plant Cooling Water system is not available
The PW Temporary cooling system was designed to cool NC when the heat load consisted of what?
One Spent fuel Pool heat exchanger
Two normal chillers at 50% load
BAC at 40% load
LRS evaporator at 50% load
Aux. Steam Vent Condenser
Can I add any more loads to the PW T-Mod then what it was intended for?
Only with the discretion of the Control Room and/or Work Control
What is the general flow path of the PW T-mod?
Two 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
What is the capacity of the PW T-Mod Portable Retention Tank?
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
What is the capacity of the two PW T-mod Circulating Pumps? What powers them?
3000 gpm each
NH
What is the PW T-Mod system’s primary makeup source?
Essential Spray Pond “A” via temporary makeup pumps