Construction and material procurement is merely the initial costs; maintenance, waste management, containment and removal are the biggest costs after that, which DO require massive costs of nation-states as it increases really fast.
Hell, SONGS still hasn't removed its spent fuel because it deems it a matter for the DOE to handle, which they won't do, and their next solution is to bury it... 100 feet from the pristine coastline (some of the most expensive in CA mind you) that lies on the San Andreas fault line, whic his where that plant and its proposed containment for Spent Fuel is.
It should also be noted that California, the largest economy in the entire US and comparable to most nations. isn't going nuclear free because its a 'feel good' selling point and won't care about the loss of energy production, but because the costs to maintain and refurbish these things has become obscene considering our ever-decreasing dependence on it.
Perspective: Japan was the 2nd largest economy at the time of 3/11 when it took over TEPCO, and Fukushima is still not contained nor have the residents been compensated for land lost nor allowed to return to their land; they're literately living a life of a refugee in their own country because of that single event . Their abysmal plan for an 'ice wall' has recently failed pathetically. You should include that and all human suffering into your cost projection model as every single one of these plants can do the same level of damage.
But truth be told, I don't think we can be 100% renewable (solar/wind/geothermal) right now, but we should strive for that and use fossil fuels to close the gaps until we can while being mindful over our consumption habits. At least we know how to do effective carbon, nitrogen sequestration via Ag based solutions and methane reclamation isn't far behind, either.
Most may think its expensive, but if we're honest about Markets being efficient at price discovery we have to understand and accept the externalities to use this technology, which if following basic Free-market logic it will in turn incentivize innovation to create a viable alternative.
Right now Nuclear is arguably THE most subsidized energy of all as its paid not just by any single nation/currency but by all cell based organisms on this planet for the 100s of millions of years as the implications extend that far in our ecosystem.
This Nuclear lobby agenda-apologist narrative has to stop being repeated already, if its so safe why don't you go live to next a Nuclear plant and see if its the fairytale you think it is. Standard radiation effluence and its health implications in the surrounding areas is poorly documented in pathology despite the cancer and heart failure rates around them. I have lived around one, and its not what you're describing at all; because when you try to find legal redress you'll find just how entrenched that industry is within the State and its 'justice' system very fast.
This even touching facts like procurement for the base raw material requires a situation like France to invade Africa to acquire it in the first place.
TL:DR You're misguided to say the least on your costs-risk benefit analysis and projections and don't follow past events at all.