I think it's more that nuclear plants are exceptionally large and complex and that makes it difficult to access economies of scale, and each new safety measure

I think it's more that nuclear plants are exceptionally large and complex and that makes it difficult to access economies of scale, and each new safety measure introduced after an accident involves additional complexity layered on top, which worsens the problem. There are so many countries with so many different cultures of regulation which have had difficulties with nuclear recently, in particular with the latest generation designs. I think you could make the situation better by having a dramatic programme to scale up nuclear, because then you can get economies of scale. That worked quite well for the French, but it means a large upfront investment, essentially paying for 50 years of energy in advance, with significant risk of cost over-runs. That requirement for front-loaded investment means the cost depends very strongly on the interest rate of money borrowed, and a low interest rate on a large, complex project requires government backing. So the fundamental reason is that governments do not have the appetite for that sort of intervention or that level of risk, like they did during the 60's-70's.