Is it actually cheaper and easier? Seawater isn’t exactly known for its ease of use and non-corrosiveness and fouling is a real problem.

Not to mention all the sea life that isn’t going to respond well to high temp water spewing out..

Nuclear subs and carriers operate in salt water all the time. It's "just" chemistry

Nuclear subs and carriers produce a fraction of the power of a commercial nuclear power plant.

I'm not sure why that matters? Salt water is salt water. An carrier's brake horsepower is ~200MW, so a fraction, but a reasonable fraction. When San Diego had a county-wide power outage in 2011, the carriers at North Island pushed power to the grid to support essential services.

smaller-size systems along with less budgetary oversight means higher maintenance costs are less likely to be problematic.

> Not to mention all the sea life that isn’t going to respond well to high temp water spewing out..

Ideally, you're not dumping the hot water back into the harbor. At least from a naive theory perspective, you could put huge cooling towers on deck and cool the reactor 100% through evaporative cooling. Bonus: the huge steam/mist cloud out of the cooling tower could help delay global warming through marine cloud brightening [0]. Whether the deck of a floating reactor has enough space and stability to support cooling towers of the appropriate size is a question for the engineers.

That's how most reactors in first world countries with temperate climates work anyway. Because it really messes up the biosphere of your river/coast, if you just dump 3GWh of thermal power straight into the water.

[0] https://en.wikipedia.org/wiki/Marine_cloud_brightening

That's too native. Output is indeed cooled but only enough to be only fraction hotter then input. Then dumping is safe again.

This is also why most of those power plants have to shut down. It's not the physical lack of water, but instead input is already so hot that output would already be over the upper limit.

Nobody build enough cooling towers to cool with them "needlessly".

Which is also why global warming is disastrous to energy sector. Those older power plants just don't have enough cooling capacity for newer higher temperatures.

> At least from a naive theory perspective, you could put huge cooling towers on deck and cool the reactor 100% through evaporative cooling.

That's usually not done with saltwater plants, because there are more issues with mineral deposit, i.e. salt.

Yes this caused major issues in France this year, the surface water was so warm it was not ecologically sound to use it for cooling so some nuclear plants had to shut down or throttle.

Seaside plants don't have this problem in France, never have, never will.

The issue happens with river plants, more specifically those that release cooling water back to the river.

This was vastly exaggerated probably to distraction the attention from the French public that the vast majority of the plants being put offline was due to the fact that they had their maintenance postponed till the limits, and then you had a bunch of reactors that, per regulations, needed to be turned-off at the same time. Only a few of the plants had this thermal problem, the ones that discharge hot water directly into the rivers.

> The usefulness of the ocean as a thermal sink though depends on water temperature which can vary a lot depending on where you are.

No. The difference between pumping water at 15°c or 30°c is negligible when you're cooling water at 325°c. You may have to pump a tiny bit more water, but that's a non-problem when you have an ocean.

Fair enough.