source: http://fas.org/rlg/2010.htm A tsunami caused by the magnitude 9.0 Tohoku Earthquake of 11 March 2011 of the northeast coast of Japan drowned the emergency diesel generators of three boiling-water reactors at Fukushima Dai-ich, resulting in station blackout and the meltdown of the three reactor cores. Although emergency injection of seawater was improvised to remove the decay heat from the reactors, it was too late to avoid boiling off of much of the water
source: http://fas.org/rlg/2010.htm A tsunami caused by the magnitude 9.0 Tohoku Earthquake of 11 March 2011 of the northeast coast of Japan drowned the emergency diesel generators of three boiling-water reactors at Fukushima Dai-ich, resulting in station blackout and the meltdown of the three reactor cores. Although emergency injection of seawater was improvised to remove the decay heat from the reactors, it was too late to avoid boiling off of much of the water