There has been more near misses in the nuclear industry than tsunamis. After Fukushima about all plants in the west had to install independent core cooling because the regulators realized the risk was systemic, even though the cause was special in the case of Fukushima.

A nuclear reactor in Sweden had a severe incident in 2006 when many of the "defense in depth" layers had been accidentally removed through freak occurrences and upgrades.

https://en.wikipedia.org/wiki/Forsmark_Nuclear_Power_Plant#J...