I think you may have missed the punchline in the story of the defective castings for the Flamanville reactor pressure vessel: the foundry responsible were exact

I think you may have missed the punchline in the story of the defective castings for the Flamanville reactor pressure vessel: the foundry responsible were exactly as good as they used to be, their previous castings going back decades and in use at existing nuclear power plants had similar defects, and they'd just managed to cover it up for all that time. I suspect the same might be true of some of the welding on the existing nuclear fleet too; they've definitely discovered some welding defects.