Fukushima 1F was a failure of governmental regulation.

It's really important to understand that, because otherwise you inescapably frame the argument wrongly. Capitalism isn't the problem, regulatory weakness is the problem. No capitalist society can survive lack of effective regulation.

(Fukushima was bad, and an example of regulatory failure, but Japan's overall effective regulatory influence over its corporations — and similarly, its mafia — is the secret sauce that has made it an economic overperformer. China can also do that — because it is a brutal dictatorship. America can't do that — and things aren't looking good. UK retains the power to do it, but it's Keystone Kops. EU can't do it, either, for reasons I can't understand at distance.

But creating safe nuclear power plants is fundamentally the same problem as creating safe elevators. In a capitalist society, it's 100% about regulatory power and competence, and nothing else.