Fukushima Daiichi Nuclear Power Plant
| Fukushima I Nuclear Power Plant | |
|---|---|
 The Fukushima 1 NPP in 2002 | |
| | |
| Country | Japan |
| Locale | Ōkuma, Fukushima |
| Coordinates | 37°25′22.7″N 141°01′58.5″E / 37.422972°N 141.032917°ECoordinates: 37°25′22.7″N 141°01′58.5″E / 37.422972°N 141.032917°E |
| Status | Units 1-4: Severely damaged, decommissioned Units 5-6: Slightly damaged, out of service |
| Construction began | July 25, 1967 |
| Commission date | March 26, 1971 |
| Operator(s) | Tokyo Electric Power Company |
| Constructor(s) | Kajima |
| Reactor information | |
| Reactors operational | 1 × 460 MWe (Unit 1 damaged) 4 × 784 MWe (Units 2, 3, and 4 damaged; Unit 5 experiencing cooling problems) 1 × 1,100 MWe (Unit 6 experiencing cooling problems) |
| Reactors planned | 2 × 1,380 MWe |
| Reactor type(s) | Boiling Water Reactor |
| Reactor supplier(s) | General Electric Toshiba Hitachi |
| Power generation information | |
| Installed capacity | 4,696 MW |
| Maximum capacity | 7,456 MW |
| Annual generation | 29,891 GW·h |
| Net generation | 877,692 GW·h |
| Website http://www.tepco.co.jp/nu/f1-np/press_f1/2010/2010-j.html | |
| As of March 14, 2011 | |
| Webcam | |
The Fukushima I Nuclear Power Plant (福島第一原子力発電所 Fukushima Dai-ichi (
pronunciation) Genshiryoku Hatsudensho, Fukushima I NPP), 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 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 I one of the 15 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 subsequent tsunami that hit Japan on March 11, 2011 and is not expected to reopen. The earthquake and tsunami disabled the reactor cooling systems, leading to nuclear radiation leaks 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.
The Fukushima II Nuclear Power Plant, or Fukushima Dai-ni, is located to the south and also run by TEPCO.
Power plant information
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. Architectural design for General Electric's units was done by Ebasco. All construction was done by Kajima. Since September 2010, Unit 3 has been fueled by a small fraction (6%) of mixed-oxide (MOX) fuel, rather than the low enriched uranium (LEU) used in the other reactors. Units 1–5 were built with Mark I type (light bulb torus) containment structures. The Mark I containment structure was slightly increased in volume by Japanese engineers. Unit 6 has a Mark II type (over/under) containment structure.
Unit 1 is a 460 MW boiling 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. In February 2011, Japanese regulators granted an extension of ten years for the continued operation of the reactor. It was damaged during the 2011 Tōhoku earthquake and tsunami.
Unit 1 was designed for a peak ground acceleration of 0.18 g (1.74 m/s) and a response spectrum based on the 1952 Kern County earthquake, but rated for 0.498 g. The design basis for Units 3 and 6 were 0.45 g (4.41 m/s) and 0.46 g (4.48 m/s) respectively. All units were inspected after the 1978 Miyagi earthquake when the ground acceleration was 0.125 g (1.22 m/s) for 30 seconds, but no damage to the critical parts of the reactor was discovered. The design basis for tsunamis was 5.7 meters.
Site layout
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, where water intake is in the middle, and discharged on either side.
Reactor data
Units 7 and 8 were planned to start construction in April 2012 and 2013 and to come into operation in October 2016 and 2017 respectively. The project was formally canceled by TEPCO in April 2011 after local authorities questioned the fact that they were still included in the supply plan for 2011, released in March 2011, after the accidents. The company stated that the plan had been drafted before the earthquake.
Electrical connections
The Fukushima Daiichi plant is connected to the power grid by four lines, the 500 kV Futaba Line (双葉線), the two 275 kV Ōkuma Lines (大熊線) and the 66 kV Yonomori line (夜の森線) to the Shin-Fukushima (New Fukushima) substation.
The Shin-Fukushima substation also connects to the Fukushima Daini plant by the Tomioka Line (富岡線). Its major connection to the north is the Iwaki Line (いわき幹線), which is owned by Tohoku Electric Power. It has two connections to the south-west that connect it to the Shin-Iwaki substation (新いわき).
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 "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 canceling plans to build Reactors No. 7 and 8.
Warnings and design critique
In 1990 the US Nuclear Regulatory Commission (NRC) ranked the failure of the emergency electricity generators and subsequent failure of the cooling systems of plants in seismically very active regions one of the most likely risks. The Japanese Nuclear and Industrial Safety Agency (NISA) cited this report in 2004. According to Jun Tateno, a former NISA scientist, TEPCO did not react to these warnings and did not respond with any measures.
Film maker Adam Curtis mentioned the risks of the type of boiling water reactors cooling systems such as those in Fukushima I, and claimed the risks were known since 1971 in a series of documentaries in the BBC in 1992 and advised that PWR type reactors should have been used.
Incidents and accident
Nuclear accidents of 2011
On 11 March 2011 an earthquake categorised as 9.0 MW on the moment magnitude scale occurred at 14:46 Japan Standard Time (JST) off the northeast coast of Japan. Units 4, 5 and 6 had been shut down prior to the earthquake for planned maintenance. The remaining reactors were shut down automatically after the earthquake, and the remaining decay heat of the fuel was being cooled with power from emergency generators. The subsequent destructive tsunami with waves of up to 14 meters (the reactors were designed to handle up to 6 meters) disabled emergency generators required to cool the reactors. Over the following three weeks there was evidence of partial nuclear meltdowns in units 1, 2 and 3: visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and a possible uncovering of the units 1, 3 and 4 spent fuel pools. Radiation releases caused large evacuations, concern about food and water supplies, and treatment of nuclear workers.
The events at units 1, 2 and 3 have been rated at Level 7 (major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures) on the International Nuclear Event Scale, and those at unit 4 as Level 3 (Serious Incident) events.
On April 3, two bodies were discovered in the basement turbine room after the workers likely ran there during the tsunami.
See also
References
External links
- Official site Tokyo Electric Company 東京電力・福島第一原子力発電所 (Japanese)
- TEPCO News, Tokyo Electric Power Company (English)
- TEPCO Webcam showing Fukushima I Nuclear Power Plant
- Archived photo. Units 1–4 can be seen from left to right.
- Radiation Dose Chart
- The Fukushima Daiichi Incident prepared by Dr. Matthias Braun - 01 April 2011, PEPA4-G, AREVA–NP GmbH (cryptome.org)
- 3D Google Earth view
- Tōhoku Region [Fukushima Prefecture (Futaba – Minamisōma) | Iwate Prefecture (Kamaishi – Miyako – Ōfunato – Ōtsuchi – Rikuzentakata – Yamada) | Miyagi Prefecture (Higashimatsushima – Ishinomaki – Kesennuma – Kurihara – Minamisanriku – Sendai)]
- Kantō Region [Ibaraki Prefecture (Kitaibaraki) | Chiba Prefecture (Ichihara)]
- Hokkaido [Oshima Subprefecture (Hakodate)]
Japanese earthquakes · Seismicity of the Sanriku coast · Historic tsunamis · Nuclear power in Japan, section Seismicity · Nuclear and radioactive incidentsRetrieved from : http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant
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