France had negative learning when attempting to scale up their nuclear industry. Assuming strong learning effects is not given. Nuclear has had 70 years of intense subsidies, and are still far from competing on the open market.
> The French nuclear case illustrates the perils of the assumption of robust learning effects resulting in lowered costs over time in the scale-up of large-scale, complex new energy supply technologies. The uncertainties in anticipated learning effects of new technologies might be much larger that often assumed, including also cases of “negative learning” in which specific costs increase rather than decrease with accumulated experience.
https://www.sciencedirect.com/science/article/pii/S030142151...