And as if this was the only problem and it hadn't a lot of huge others, nuclear proponents will use this now as an example how nuclear is the way out of the climate crisis, and how comparing nuclear with renewables is wrong..
No, the best future would be neither fossil nor nuclear.
nuclear is the highest density of energy available to mankind. Refusing to using it is kind of a huge missed opportunity.
In Finland, the coldest weather is experienced when, during winter months, there is a persistent anticyclone parked overhead. Those can cover the entirety of the country, and inside them there is negligible wind. For example, on 8th of December it was -20°C, and the average output of wind power (nominal installed capacity ~2800MW) over the day was 330MW. The average output of grid-connected solar was <1MW (It's December in Finland, what did you expect?).
Anticyclones can remain in place overhead for weeks. The value often used to calculate the cost of renewable+storage is 3h. This is a reasonable value for California, where solar production correlates well with use. If you built the grid in Finland based on that, we would just die when it gets cold.
There are no renewables that work well in Finland. Water power is fully built out. Solar only produces power when we don't need it. Wind reliably does not provide power when we need it. Compared to renewable with enough storage, even with all it's overruns, OL3 is remarkably cheap.
Many current heating fuels are fossil and not great either, but they can be replaced with renewable fuels which solves storage vs renewable-produced electricity.
Do you propose to build so many nuclear plants that you can provide peak electricity including heating in cold winter months? Do you have numbers for that? (I imagine that'd be the most expensive solution ever, as nuclear plants are high in capital costs and you're basically proposing to have lots of nuclear plants that only run on very cold winter days.)
I guess what many nuclear proponents seem to forget is that you need flexibility no matter what source of electricity you have - because even if your plant runs 24/7 (which it doesn't), energy needs aren't constant.
France's EDF takes more nuclear reactors offline after faults found - 2021-12-17
https://www.reuters.com/markets/europe/edf-extend-civaux-nuc...
Next year, I think, they're building a storage not far from where I live with 200.000 m³ capacity.
For individual house heating it is some combination of pure electric, heat pump, wood and oil.
Gas in general is used very little for electricity here (only ~7% of total energy production) and gas cooking stuff is also relatively rare.