> Humans were not responsible

Well, yes and no:

"TEPCO, that operated the station, had been warned their seawall was insufficient to withstand a powerful tsunami, but the seawall height was not raised in response." https://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Powe...

I agree with your general sentiment, but I would say that humans are the biggest threat in nuclear power.

The structure stood up fine, we know how to build for that, it was the placement of the air fed diesel generators in a floodable basement that screwed Fukashima.

Structure was probably the wrong word, I meant more the plant as a whole. I think my point still remains... it would be a very rare structure that wouldn't have a design flaw exposed by such a large earthquake/tsunami one-two punch.

How about Onagawa Nuclear Power Plant, the closest nuclear plant to the epicenter, which remained almost undamaged after the 14 meter seawall kept out the tsunami.

edit - also, if you design for tsunami, the two-punch scenario is your design brief.