There has been a major back-logging in nuclear equipments investments, so big in fact, that some countries who should by right be netto exporters of energy (france) became importers. Its a valid technology in a theoretical world, that does all the upkeep measures, does actual credible threat analysis.
In 2014 the government they elected basically went all in switching to renewables and they actually stopped or delayed a lot of stuff.
That said, well, they stopped building new reactors, most of their reactors were built in 15 years in the 70/80s. Since then they have not done as much as they should have and all those reactors are starting to need more maintenance now.
Because they have not built much new things, they don't have as many people with knowledge as they used to.
But they are managing most of these issues pretty well overall.
I would say France did pretty well having 40 years of green energy.
I have yet to see such a world.