I have no idea. I don't even know if it is practically possible to manage well enough to guarantee zero disasters.

But there are many nuclear plants around the world that have operated with no problems. As I said, I'm no expert.

new design exist that in case of disaster self contains under most conditions, trouble is it's very hard to obtain certifications needed for operation today as opposed to decades ago, so we're mostly stuck with old designs.

The UK seems pretty good at it: https://en.wikipedia.org/wiki/Nuclear_power_in_the_United_Ki...

by design already. all recent reactors have containment tanks to prevent radioactive leakage in a meltdown event.