What is that smoke stuff that rises out of nuclear power plants? Is it pollution, and if so, what type of pollution? Or is it just steam?

The majority of what you see coming from these massive cooling towers is water vapour. Nuclear power plants require these large cooling towers to condense the steam back into water, which then cycles back to the reactor to be heated up again, turned to steam, and the steam powers an electrical generator.

The "smoke stuff" that rises out of nuclear power plants is actually water vapor, not smoke. It is commonly referred to as steam. When water is heated to produce steam in nuclear power plants, it is used to drive turbines that generate electricity. This process does not produce pollution in the traditional sense, as it does not release harmful gases or particulate matter into the atmosphere. However, while the steam itself is not considered pollution, nuclear power plants do produce other forms of waste, such as radioactive byproducts, which must be carefully managed to prevent environmental contamination.