Why does nuclear have a niche in a green future? I don't see it surviving. Locations with insufficient wind/solar will be supplied externally, either by grid or by transport of synthetic chemical fuels. Places like very high latitudes (where wind is often very good, btw) are so sparsely populated they cannot by themselves sustain a nuclear industry.
Building cables across the ocean raises much more demanding engineering problems but much less demanding political problems than building them across multiple states. You don't have to please a bunch of different regional governments and land owners when you're building across the ocean. If you have a government that can dictate national projects like in China you can build long cables over land even faster, but that political alternative also comes with its own problems (to put it mildly).
When the entire Railbelt grid in Alaska (the largest grid there) has an average load of 600 MW, there simply isn't much market for SMRs at high latitudes.
