Question: what happened at the fukushima nuclear power plant

title: Fukushima Daiichi nuclear disaster
text: The Fukushima Daiichi nuclear disaster ( 福島 第 一 原子力 発電 所 事故 , Fukushima Dai - ichi ( pronunciation ) genshiryoku hatsudensho jiko ) was an energy accident at the Fukushima Daiichi Nuclear Power Plant in Ōkuma , Fukushima Prefecture , initiated primarily by the tsunami following the Tōhoku earthquake on 11 March 2011 . Immediately after the earthquake , the active reactors automatically shut down their sustained fission reactions . However , the tsunami disabled the emergency generators that would have provided power to control and operate the pumps necessary to cool the reactors . The insufficient cooling led to three nuclear meltdowns , hydrogen - air explosions , and the release of radioactive material in Units 1 , 2 and 3 from 12 March to 15 March . Loss of cooling also raised concerns over the recently loaded spent fuel pool of Reactor 4 , which increased in temperature on 15 March due to the decay heat from the freshly added spent fuel rods but did not boil down to exposure . 

Answer: answer: The Fukushima Daiichi nuclear disaster is initiated primarily by the tsunami following the Tōhoku earthquake on 11 March 2011.  The tsunami disabled the emergency generators that would have provided power to control and operate the pumps necessary to cool the reactors.  The insufficient cooling led to three nuclear meltdowns, hydrogen-air explosions, and the release of radioactive material in Units 1, 2 and 3 from 12 March to 15 March.