Close up of cooling towers
Reactor steam is condensed into water and then returned to the reactor. The primary coolant water is not mixed with the secondary cooling water. The primary water is purified to the point it will not conduct electricity. Energy NW takes great care in keeping the primary coolant pure.

The secondary cooling water comes from the river and cools as it travels down through the tower. The objects at top vent released steam. The towers vent 20-30,000 gallons of water a minute.