Satellite image on 16 March of the four damaged reactor buildings
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| Date | 11 March 2011 (2011-03-11)–ongoing |
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| Time | 14:46 JST (05:46 UTC) |
| Location | Ōkuma, Fukushima, Japan |
| Coordinates |  37°25′17″N 141°1′57″E / 37.42139°N 141.0325°E / 37.42139; 141.0325 |
| Outcome | INES Level 7 (ratings by Japanese authorities as of 11 April)[1][2] |
| Reported injuries | 37 with physical injuries,[3] 2 workers taken to hospital for radiation exposure[4] |
| Reported death(s) | 1 (heart attack)[5] |
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The Fukushima Daiichi nuclear disaster (福島第一原子力発電所事故, Fukushima Dai-ichi (
pronunciation) genshiryoku hatsudensho jiko?) is a series of equipment failures, reactor core melts, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the 9.0 magnitude Tōhoku earthquake and tsunami on 11 March 2011.[6][7] The plant comprises six separate boiling water reactors maintained by the Tokyo Electric Power Company (TEPCO). This accident is the largest of the 2011 Japanese nuclear accidents arising from the Tōhoku earthquake and tsunami, and experts consider it to be the second largest nuclear accident after the Chernobyl disaster, but more complex as multiple reactors are involved.[8]
At the time of the quake, Reactor 4 had been de-fueled while 5 and 6 were in cold shutdown for planned maintenance.[9] The remaining reactors shut down automatically after the earthquake, with emergency generators starting up to run the control electronics and water pumps needed to cool reactors. The plant was protected by a seawall designed to withstand a 5.7 m (19 ft) tsunami but not the 14 m (46 ft) maximum wave which arrived 41–60 minutes after the earthquake.[10] The entire plant was flooded, including low-lying generators and electrical switchgear in reactor basements and external pumps for supplying cooling seawater. The connection to the electrical grid was broken. All power for cooling was lost and reactors started to overheat, owing to natural decay of the fission products created before shutdown. The flooding and earthquake damage hindered external assistance.
Read more at: http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents
