Or perhaps we have different ideas of what "reasonable" assumptions about costs will be in ten years.

I expect nuclear to show little or no cost decline in that time. And I expect renewables to have shown large continued declines. I expect solar to have fallen by a factor of 2. Given that sort of decline, even low efficiency seasonal storage could beat nuclear.

High latitude regions -- what latitude are you talking about? 95% of the world's population is below 50 N/S. For the few in true polar regions, I suggest solar + moderate temperature geothermal could be a good combination. Geothermal would be used in the winter, when a very low temperature heat sink is available.

In a solar dominated future, I expect those high latitude regions to eventually lose most of their energy-intensive industry. They will not be able to compete with industries at lower latitude with better access to cheaper solar power. Having expensive nuclear available there will not save them from this.

To assume nuclear won't be making any cost reductions is to basically beg the question.

We're discussing whether we should invest in nuclear. Renewables have reduced in price because of investment. Nuclear has not because we have dramatically reduced our investments there over the last several decades. If we invest again in nuclear, there will be cost reductions from the learning curve. If we don't, there won't be cost reductions.

IMHO, climate demands we invest in every promising resource. And that includes nuclear.

No, it's to respect the evidence. Nuclear has a history. That history shows a stubborn lack of progress in reducing costs. In contrast, solar has shown spectacular and sustained cost reductions.

Governments have invested very heavily in nuclear, much more so than in renewables. To pretend there hasn't been investment is disingenuous in the extreme.