The proximate cause of the nuclear disaster was the 2011 Tohoku earthquake and tsunami natural disaster that occurred on 11 March 2011 and was the most powerful earthquake ever recorded in Japan. The earthquake triggered a powerful tsunami, with 13–14 meter high waves... Wikipedia
Of course the poorly chosen site of the nuclear power plant exacerbated the problems.
https://www.ctvnews.ca/sci-tech/japan-considering-developmen…
SCI-TECH News
Updated Aug. 24, 2022 10:27 a.m. ADT
Japan considering development of new nuclear reactors
TOKYO - Japanese Prime Minister Fumio Kishida on Wednesday instructed his government to consider developing safer, smaller nuclear reactors, signaling a renewed emphasis on nuclear energy years after many of the country’s plants were shut down.
Kishida made the comment at a “green transformation” conference on bolstering the country’s efforts to curb emissions of greenhouse gases. Japan has pledged to reach carbon neutrality by 2050.