Fukushima Daiichi Nuclear Disasterr

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FUKUSHIMA DAIICHI NUCLEAR DISASTER
Date: March 11, 2011
Location: Ōkuma, Fukushima, Japan
Construction began: July 25, 1967 (Fukushima I - 1)
Commission date: March 26, 1971 (Fukushima I - 1)
Operator(s): Tokyo Electric Power Company (TEPCO)
Constructor(s): Kajima
Injuries: 37 with physical injuries, 2 workers taken to hospital with radiation burns.

THE POWERPLANT

The Fukushima I Nuclear Power Plant also known as Fukushima Dai-ichi (dai-ichi means "number one"), is a disabled nuclear power plant located on a 3.5-square-kilometre (860-acre) site[1] in the towns of Okuma and Futaba in the Futaba District of Fukushima Prefecture, Japan. First commissioned in 1971, the plant consists of six boiling water reactors (BWR). These light water reactors drove electrical generators with a combined power of 4.7 GWe, making Fukushima Daiichi one of the 15 largest nuclear power stations in the world. Fukushima I was the first nuclear plant to be designed, constructed and run in conjunction with General Electric, Boise, and Tokyo Electric Power Company (TEPCO).[3] The plant suffered major damage from the 9.0 earthquake and subsequent tsunami that hit Japan on March 11, 2011 and, as of December 2012, is not expected to reopen. The earthquake and tsunami disabled the reactor cooling systems, leading to releases of radioactivity and triggering a 30 km evacuation zone surrounding the plant. On April 20, 2011, the Japanese authorities declared the 20 km evacuation zone a no-go area which may only be entered under government supervision. As of April 2012, Units 1-4 are no longer in operation. Units 2-4 shut down on April 19, 2012, while Unit 1 was the last of these four units to shut down on April 20. The Fukushima II Nuclear Power Plant, or Fukushima Dai-ni ("number two"), is located to the south and also run by TEPCO.

SITE LAYOUT
The location of the plant was on a bluff which was originally 35-meters above sea level. During construction, however, TEPCO lowered the height of the bluff by 25-meters. One reason the bluff was lowered was so that the base of the reactors could be constructed on solid bedrock to mitigate the threat posed by earthquakes. Another reason was the lowered height would keep the running costs of the seawater pumps low. TEPCO did not factor in the tsunami risk when planning the site's construction. Therefore, the lowered height would result in the plant being more vulnerable to tsunami. The Fukushima Daiichi site is divided into two reactor groups, the leftmost group when viewing from the ocean contains units 4, 3, 2 and 1 going from left to right. The rightmost group when viewing from the ocean contains the newer units 5 and 6, respectively the positions from left to right. A set of seawalls protrude into the ocean, with the water intake in the middle and water discharge outlets on either side.

OPERATING HISTORY
The plant reactors came online from 1970 through 1979. From the end of 2002 through 2005, the reactors were among those shut down for a time for safety checks due to the TEPCO data falsification scandal. On Feb 28, 2011 TEPCO submitted a report to the Japanese Nuclear and Industrial Safety Agency admitting that the company had previously submitted fake inspection and repair reports. The report revealed that TEPCO failed to inspect more than 30 technical components of the six reactors, including power boards for the reactor's temperature control valves, as well as components of cooling systems such as water pump motors and emergency power diesel generators. In 2008, the IAEA warned Japan that the Fukushima was built using outdated safety guidelines, and could be a "serious problem" during a large earthquake.  The warning led to the building of an emergency response center in 2010, used during the response to the 2011 nuclear accident.

On 4 April 2011, TEPCO vice president Takashi Fujimoto announced that the company was cancelling plans to build Reactors No. 7 and 8. On May 20 TEPCO's board...
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