If plants were still being built to 1960s standards, we'd have many Fukushima type reactors that can't survive a loss of plant power. The US still has some of those, Peach Bottom, Pennsylvania being the best known.
There's a lot to be said for a big, strong containment vessel. That's why the Three Mile Island meltdown was an expensive accident but didn't injure anyone. Maybe if the industry just got better at big, strong containment vessels cheaply...