Entrainment: Takes place when small organisms, such as eggs and larvae, are sucked into a power plant’s cooling system along with the massive withdrawal of cooling waters from a water body.

Impingement: Occurs when larger fish (and other aquatic organisms) are trapped against the screens that filter large debris from the intake structures during cooling water withdrawal.

Once-Through Cooling: Water is drawn into the power plant from a local body of water to absorb heat and is then discharged back into the water body at an elevated temperature.

Closed-Cycle Cooling: In a closed-cycle wet cooling system, cooling water is circulated first through the plant to absorb heat, then through cooling cells to evaporate heat to the atmosphere and condense steam back to liquid to be recirculated through the plant. A closed-cycle dry cooling system uses radiator-type coils to transfer heat to air passing over the coils.