Afaik, nuclear energy is more expensive only because it is regulated far beyond what any other form of energy for the same level of risk.
Disposal of nuclear waste is a huge expense, but the main waste product generated by natural gas (CO2) gets away scot free despite literally being the cause of what might be our generation's biggest problem.
The end-of-life expenses of nuclear plants are included in the cost sheets, but dams get away scot free.
Material procurement is justifiably expensive, since security measures for handling nuke-fuel are far more stringent. But, that is more a virtue of global politics than the actual cost of nuclear energy.
Another cold-start problem is that the USA does not have the same experience with frequently building nuclear plants, vs say a country like France has. Thus, any new contractor spends extra money to be the first to wade through bureaucratic / training related challenges that would otherwise have been resolved if building nuclear plants was more common place.
Just saying, the numbers for energy source comparison aren't always as fair as they look.
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> Attaching four hours of storage to a solar generation farm, just enough to get through the duck curve, is now slightly cheaper than coal.
Wow, I didn't know we were that close to dealing with the storage/temporal variability problem. If we can solve that problem with money to spare, then I can see the adoption of solar + wind going up through the roof.