Likely no real effect once you get a short distance away from them, if any at all.
No way. Plenty of research has been done on the effects of thermal effluent from power plants (though mostly in rivers, I think). It's not harmless.
As a point of reference,
a study on effects of coastal nuclear power that discharges their heated cooling water back to the ocean
Okay, that's
one paper. Did you do a literature survey, or just pick the first hit that said what you wanted to hear?
Also, if you look at where that paper's authors work, we should be skeptical about what kind of bias they might have. With one being from the Ministry of Natural Resources, I think it's unlikely they'd produce a paper finding that it's particularly harmful.
In case people want to do their own research:
And the amount of thermal energy being output from a nuclear plant will far exceed that of a data center.
Datacenter energy usage is currently on an exponential growth curve. How long before we see datacenters integrated with their own nuclear plants? If you can "solve" the cooling problem, I think it's probably not long.
With that said, a datacenter is going to have an environmental impact, no matter where you put it. I'm still skeptical this is the best option. Wherever you put them, I think improving computational efficiency needs to be the top priority.
What strikes me as weird about the idea is that technology changes so rapidly - I think the typical upgrade cycle for datacenters is around 3-4 years. Most server components and equipment are only warrantied for 5 years, so that should be the practical maximum. However, the article highlights how troublesome and presumably expensive it is to raise and lower the units. Maybe if you build it with enough redundancy that it doesn't need regular service, then it's still viable just to raise & service each module every 3.5 years or so?
If you compare AI hardware to 3.5 years ago, it's even worse. Back then, Nvidia's V100 still ruled the roost. Seems like the upgrade cycle for AI hardware is probably more like 2 years.