If the biggest externality is heated water in a subarctic climate, or nuclear waste that gets stored on-site indefinitely in casks and produces no notable leaks or accidents (like has been done in the US for a long time now), the externalities are way less than literally any other form of energy production. That includes Dams, solar power, geothermal, wind, you name it.

No, people aren’t pretending that. Heat pollution in water is a tiny local issue compared to global warming.

It’s like complaining that a wool blanket is itchy so it might be better to catch hypothermia and die.

What prevents heated waste water from being used for…heat? Surely Finland uses central heating plants that pump hot water throughout the city (or maybe that’s just a Chinese/Russian thing?). What makes waste heat water less suited to heating, higher entropy?

> And heat-polluted waste waters?

That's hardly unique to nuclear plants; in particular, coal plants typically have lower thermal efficiency.