The French buildout was very definitely a reaction to the oil crisis.
https://en.wikipedia.org/wiki/Nuclear_power_in_the_United_Ki... describes a similar process of thinking in the UK, which was abandoned in favor of privatizing the industry, and the PWRs were never built apart from Sizewell B.
I suspect the arrival of North Sea oil and gas eased the energy concerns in the 1980s.
> Instead we have the Chinese taking 30 years to build our new reactor.
It's still owned by the same company that operates all the French nuclear reactors, EDF, and I suspect that most of the people doing the actual work on site are British. China can certainly build new reactors in China. I wonder if it's same the general disease of Western project management which causes high speed rail to get more and more expensive and less feasible.