Nuclear’s probably not a great long term choice since it’s a lot more expensive than renewables.
But that’s just the generated per kwh cost, not taking into account when the energy is generated. To compare a full renewables grid to a renewables nuclear mixed grid you need to take into account massive energy storage systems and their inefficiencies and possible material shortages. We can’t just compare the currently favorable cost per kwh without taking into account problems as we scale into less reliable energy sources.
You will need long term storage in both cases. Nuclear can’t act as a peaker because you can’t quickly ramp up or down the generation. Nuclear can only perform as baseload which, in theory, could be provided by a renewable energy mix if the install base is high enough.
I don’t disagree with your point that it isn’t a simple direct comparison but any sensible energy mix will still require storage. I find it difficult to see the economic case for nuclear if renewables can be installed in sufficient quantities, given that nuclear is roughly 4 times as expensive as solar and wind.
Nuclear can only perform as baseload
That’s only true for NPPs built decades ago. Modern designs can also do load-following power. For peaks you have renewables, of course, they complement each other. Diversity makes a healthy grid.
With 100% renewables you would need almost 100% storage and potentially for multiple days, with a nuclear baseload you’d only need storage for the peaks, you could even use excess renewables to charge up the storage for these peaks.
France, with all it’s maintainance disasters with their nuclear reactors shows us yet another problem: how to properly cool the water for the generator? With sinking fresh-water levels in rivers and fastly rising water temperatures nuclear reactors become less reliable. Wind and solar output on the other side will in an ironical way get a little more reliable, as there will be more of both.
