Contents

Fukushima Daiichi Nuclear Power Plant

Fukushima I Nuclear Power Plant
The Fukushima 1 NPP in 2002
Country	Japan
Coordinates	37°25′17″N 141°01′57″E / 37.4214°N 141.0325°E / 37.4214; 141.0325
Status	Damaged, out of service
Construction began	July 25, 1967 (1967-07-25)
Commission date	March 26, 1971 (1971-03-26)
Decommission date	11 March 2011
Owner(s)	TEPCO
Operator(s)	Tokyo Electric Power Company
Power generation
Nameplate capacity	0 MW
External links
Website	www.tepco.co.jp/en/nu/press/f1-np/index-e.html
Commons	Related media on Commons
[edit on Wikidata]

The Fukushima I Nuclear Power Plant (福島第一原子力発電所, Fukushima Dai-Ichi Genshiryoku Hatsudensho, Fukushima I NPP), often referred to as Fukushima Dai-ichi (Dai-ichi simply means firstornumber 1), is a nuclear power plant located in the town of Okuma in the Futaba DistrictofFukushima Prefecture, Japan, first commissioned in 1971. The plant consists of six boiling water reactors. These light water reactors have a combined power of 4.7 GW, making Fukushima I one of the 25 largest nuclear power stations in the world. Fukushima I was the first nuclear plant to be constructed and run entirely by the Tokyo Electric Power Company (TEPCO). The plant suffered major damage from the 9.0 earthquake and following tsunami that hit Japan on March 11, 2011, disabling the reactor cooling systems and triggering a widespread evacuation surrounding the plant.

The Fukushima II Nuclear Power Plant, 11.5 kilometres (7.1 mi) to the south, is also run by TEPCO.

Reactors

The reactors for Units 1, 2, and 6 were supplied by General Electric, those for Units 3 and 5 by Toshiba, and Unit 4 by Hitachi. All six reactors were designed by General Electric.^[1] Architectural design for General Electric's units was done by Ebasco. All construction was done by Kajima.^[2] Since September 2010, Unit 3 has been fueled by mixed-oxide (MOX) fuel, rather than the low enriched uranium (LEU) used in the other reactors.^[3][4] Units 1–5 were built with Mark I type (light bulb torus) containment structures, Unit 6 has a Mark II type (over/under) containment structure.^[5][6][7]

Unit 1 is a 460 MWboiling water reactor (BWR-3) constructed in July 1967. It commenced commercial electrical production on March 26, 1971, and was initially scheduled for shutdown in early 2011.^[8] In February 2011, Japanese regulators granted an extension of ten years for the continued operation of the reactor.^[9] It was damaged during the 2011 Sendai earthquake and tsunami.^[10] Unit 1 was designed for a peak ground acceleration of 0.18 g (1.74 m/s²) and a response spectrum based on the 1952 Kern County earthquake.^[5] All units were inspected after the 1978 Miyagi earthquake when the ground acceleration was 0.125 g (1.22 m/s²) for 30 seconds, but no damage to the critical parts of the reactor was discovered.^[5]

Reactor data

Operating history

The plant had reactors come online from 1970 through 1979. There was a period of time from the end of 2002 through 2005, where the reactors were shut down for urgent safety checks due to the TEPCO data falsification scandal.^[14][15]

Effects of 2011 earthquake and tsunami

This section documents a Fukushima I nuclear nuclear incident. Information may change rapidly as the event progresses, and initial news reports may be unreliable. The latest updates to this section may not reflect the most current information. Feel free to improve this section or discuss changes on the talk page, but please note that updates without valid and reliable references will be removed. (March 2011) (Learn how and when to remove this message)

On 11 March 2011 an earthquake categorised as 9.0 M_W on the moment magnitude scale occurred at 14:46 Japan Standard Time (JST) off the northeast coast of Japan. The effects of the natural disaster led to cooling problems in reactors 1, 2 and 3 followed by accidents at the Fukushima I nuclear power plant, rated by Japan's nuclear safety agency at level 4 (accident with local consequences) on the International Nuclear Event Scale (INES).^[16] Over 200,000 people were evacuated after officials voiced the possibility of a meltdown.^[17][18] The external structure of Units 1, and 3 collapsed after hydrogen explosions. The containment building of Unit 1 and 3 remained intact, but Unit 2 was feared damaged following an explosion within it.^[19] On 15 March 2011, the Unit 4 fuel pond caught fire,^[20][21] increasing radiation levels and prompting more evacuations.^[22] Chief Cabinet Secretary Yukio Edano announced that according to the Tokyo Electric Power Company, the hourly radiation reached up to 400,000 μSv,^[23][24] but as of later the same day they are reducing^[25]. At the same time it was announced that temperatures are gradually rising in the #5 and #6 reactors^[26].

Reactors 1, 2 and 3 have been filled with seawater^[27] and are likely to be decommissioned, since it is not cost effective to decontaminate.^[28] Reactor 4 was active at the time of the earthquake.^[29]

See also

• 2011 Japanese nuclear incidents
• List of boiling water reactors

References

External links

• Media from Commons

News from Wikinews

• Official site c/o Tokyo Electric Company 東京電力・福島第一原子力発電所
• Archived photo. Unit 1-4 can be seen from left to right.