Salt water is famously a forgiving environment to build in, and oceanic weather is benign and predictable. Not that it would be a problem anyway, because move-fast-and-break-things people can be trusted to do the right thing when it comes to running delicate equipment in places more hostile than mid california, and will not skimp on staffing and maintenance. You can look at all the the successful seasteading operations to see how well this will go.

There are also no problems I can foresee with putting a bucketload of fissiles in international waters, with no scope for finally uniting old-school piracy with new-school piracy, either. This plan is great, and no-one will have a problem with it.

but you see, in case of accident they can just dump reactor core into seawater which will provide ample cooling and shielding. no biggie, just put multi thousand ton object that requires a village of engineers to work out on high seas

there are normal nuclear powerplants that use seawater as coolant and they're all on shore. these require a lot of corrosion resistant heat exchangers along the way. there is one power barge like this, it provides power to russian far east, whole 70MW of it, costed 414 million dollars and needs 300 people onsite. your guess is as good as mine how many of them are military. 70MW, aka two or three aeroderivative gas turbines