Indeed, but that’s only because so many people are insisting on one-piece forgings (and surely it’s for a containment vessel, not the containment dome?). From that very link:
In a hypothetical Great Nuke Building Boom this is just one of the many safety standards that would need to be relaxed. Just how far standards would need to be dropped in order to let e.g. the US build 400 plants in a decade I don’t know - probably a lot further than anyone would be comfortable with.