March 11, 2011, knocked out backup power systems that were needed to cool the reactors at the
plant, causing three of them to undergo fuel melting, hydrogen explosions, and radioactive
releases. Radioactive contamination from the Fukushima plant forced the evacuation of
communities up to 25 miles away and affected up to 100,000 residents, although it did not cause
any immediate deaths.
Tokyo Electric Power Company (TEPCO) operates the Fukushima nuclear power complex in the
Futaba district of Fukushima prefecture in Northern Japan, consisting of six nuclear units at the
Fukushima Daiichi station and four nuclear units at the Fukushima Daini station. All the units at
the Fukushima complex are boiling water reactors, with reactors 1 to 5 at the Fukushima Daiichi
site being the General Electric Mark I design, which is also used in the United States. The
Fukushima Daiichi reactors entered commercial operation in the years from 1971 (reactor 1) to
1979 (reactor 6). The Fukushima Daini reactors shut down automatically after the earthquake and
were able to maintain sufficient cooling.