Introduction
In Japan, the 2011 off the Pacific coast of Tohoku Earthquake occurred at 14:46 on 11 March 2011. [7] At the Fukushima Daiichi Nuclear Power Station (Fukushima Daiichi NPS), [8] operated by the Tokyo Electric Power Company (TEPCO), the earthquake and tsunami caused the compound accident (hereinafter called Fukushima Daiichi Nuclear Accident) consisting of Station BlackOut (SBO) incident, Unit 1, 2, 3 severe core damage accidents, Unit 1, 2, 4 hydrogen explosion accidents, radioactive releases [9] [10] and so on. [11]
In response to the early events of this accident, Japanese government declared a nuclear emergency situation and established the Nuclear Emergency Response Headquarters (NERHQ), which instructed the Fukushima Prefectural Governor and relevant local governments to issue an evacuation order to citizens from the nearby Fukushima Daiichi NPS. [12]
Significant amounts of radioactive material have also been released into ground and ocean waters. Measurements taken by the Japanese government 30–50 km from the plant showed caesium-137 levels high enough to cause concern, leading the government to ban the sale of food grown in the area. [13] [14]
A few of the plant's workers were severely injured or killed by the disaster conditions resulting from the earthquake. There were no immediate deaths due to direct radiation exposures, but at least six workers have exceeded lifetime legal limits for radiation and more than 300 have received significant radiation doses. Predicted future cancer deaths due to accumulated radiation exposures in the population living near Fukushima have ranged from none [15] to 100 [16] to a non-peer-reviewed "guesstimate" [17] of 1,000. On 16 December 2011, Japanese authorities declared the plant to be stable, although it would take decades to decontaminate the surrounding areas and to decommission the plant altogether. [18]
A process overview of the accident
At the Fukushima Daiichi NPS, all the off-site power supply was lost due to the earthquake. Later, the subsequent arrival of the tsunami caused flooding of many cooling seawater pumps, emergency diesel generators (EDGs), and power panels which were housed in low-lying rooms. [19] This resulted in the total loss of AC power at Units 1 through 5. As nuclear reactor coolant systems stopped for a long time from cutting power, the reactors overheated due to the normal high radioactive decay heat produced [20] in the first few days after nuclear reactor shutdown. [21]
As the water boiled away in the reactors and the water levels in the fuel rod pools dropped, the reactor fuel rods began to overheat severely, and to melt down. In the hours and days that followed, Reactors 1, 2 and 3 experienced full meltdown. [22] [23]
In the intense heat and pressure of the melting reactors, a reaction between the nuclear fuel metal cladding and the remaining water surrounding them produced explosive hydrogen gas. As workers struggled to cool and shut down the reactors, several hydrogen-air chemical explosions occurred. [24] [25]
Investigation Groups
- National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission
The National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) was established by the National Diet of Japan as the first independent investigation commission on 8 December 2011. [26]
On 5 July 2012, NAIIC released an executive summary report [27] of The Fukushima Nuclear Accident. The panel is due to deliver its final report at the end of July. [28]
- Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company
The Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company (ICANPS) was established by the Cabinet decision on 24 May 2011. [29]
On 2 December 2011, ICANPS issued an interim report. [30] On 23 July 2012, the government appointed the committee submitted its final report to the Japanese government. [31]
- TEPCO Internal Investigation
On 20 June 2012, TEPCO released its final internal investigation report. In the report, TEPCO complained that top politicians, including the prime minister, interfered with recovery efforts during the initial stages of the disaster by making specific requests that were out of touch with what was actually taking place at the plant. TEPCO concluded that the direct cause of the accident was the tsunami which knocked out the reactors' cooling system. TEPCO also admitted that it was at fault in not being prepared for the situation, but said that its workers did the best they could "amid unprecedented circumstances." [32]
Tepco admitted for the first time on 12 October 2012 that it had failed to take stronger measures to prevent disasters for fear of inviting lawsuits or protests against its nuclear plants. [33] [34] [35]
- Others
As part of the government inquiry, the House of Representatives of Japan's special science committee directed TEPCO to submit to them its manuals and procedures for dealing with reactor accidents. TEPCO responded by submitting manuals with most of the text blotted out. In response, the Nuclear and Industrial Safety Agency ordered TEPCO to resubmit the manuals by 28 September 2011 without hiding any of the content. TEPCO replied that it would comply with the order. [36]
On 24 October NISA published a large portion of Tokyo Electric Power Company's procedural manuals for nuclear accidents. These were the manuals that the operator of the Fukushima Daiichi nuclear power plant earlier did send to the Lower House with most of the contents blacked out, saying that this information should be kept secret to protect its intellectual property rights, and that disclosure would offer information to possible terrorists. NISA ordered TEPCO to send the manuals without any redaction, as the law orders. 200 pages were released from the accident procedural manuals used for Fukushima Daiichi nuclear power plant. All their contents were published, only the names of individuals were left out. [37]
The agency said, the decision to publish the manuals was taken, for transparency in the search what caused the nuclear accident in Fukushima and also to establish better safety measures for the future. [38]
On 24 October 2011 the first meeting was held by a group of 6 nuclear energy specialists invited by NISA to discuss the lessons to be learned from the accidents in Fukushima. [39]
On 28 February 2012, the Independent Investigation Commission on the Fukushima Nuclear Accident by the Rebuild Japan Initiative Foundation announced an investigation report. [40]
Oregon's United States Senator Ron Wyden toured the plant and issued a statement that the situation was "worse than reported." He sent a letter to Japanese Ambassador Ichiro Fujisaki urging Japan to seek international help to relocate spent fuel rods stored in unsound structures and prevent leakage of dangerous nuclear material. [41] [42]
A nuclear and radiation accident is defined by the International Atomic Energy Agency (IAEA) as "an event that has led to significant consequences to people, the environment or the facility. Examples include lethal effects to individuals, large radioactivity release to the environment, reactor core melt." The prime example of a "major nuclear accident" is one in which a reactor core is damaged and significant amounts of radioactive isotopes are released, such as in the Chernobyl disaster in 1986 and Fukushima nuclear disaster in 2011.
Tokyo Electric Power Company Holdings, Incorporated, also known as Toden or TEPCO, is a Japanese electric utility holding company servicing Japan's Kantō region, Yamanashi Prefecture, and the eastern portion of Shizuoka Prefecture. This area includes Tokyo. Its headquarters are located in Uchisaiwaicho, Chiyoda, Tokyo, and international branch offices exist in Washington, D.C., and London. It is a founding member of strategic consortiums related to energy innovation and research; such as JINED, INCJ and MAI.
The Fukushima Daiichi Nuclear Power Plant is a disabled nuclear power plant located on a 3.5-square-kilometre (860-acre) site in the towns of Ōkuma and Futaba in Fukushima Prefecture, Japan. The plant suffered major damage from the magnitude 9.1 earthquake and tsunami that hit Japan on March 11, 2011. The chain of events caused radiation leaks and permanently damaged several of its reactors, making them impossible to restart. The working reactors were not restarted after the events.
The Fukushima Daini Nuclear Power Plant Genshiryoku Hatsudensho, Fukushima II NPP, 2F) is a nuclear power plant located on a 150 ha (370-acre) site in the town of Naraha and Tomioka in the Futaba District of Fukushima Prefecture, Japan. The Tokyo Electric Power Company (TEPCO) runs the plant.
The Fukushima nuclear accident was a major nuclear accident at the Fukushima Daiichi nuclear power plant in Ōkuma, Fukushima, Japan which began on March 11, 2011. The proximate cause of the accident was the 2011 Tōhoku earthquake and tsunami, which resulted in grid failure and damaged nearly all of the power plant's backup energy sources. Notably, subsequent inability to sufficiently cool reactors after shutdown compromised containment and resulted in the release of radioactive contaminants into the surrounding environment. The accident was rated seven on the INES by NISA, following a report by the JNES.
Fukushima Daiichi is a multi-reactor nuclear power site in the Fukushima Prefecture of Japan. A nuclear disaster occurred there after a 9.0 magnitude earthquake and subsequent tsunami on 11 March 2011. The earthquake triggered a scram shut down of the three active reactors, and the ensuing tsunami crippled the site, stopped the backup diesel generators, and caused a station blackout. The subsequent lack of cooling led to explosions and meltdowns, with problems at three of the six reactors and in one of the six spent-fuel pools.
The international reaction to the 2011 Fukushima Daiichi nuclear disaster has been diverse and widespread. Many inter-governmental agencies responded to the Japanese Fukushima Daiichi nuclear disaster, often on an ad hoc basis. Responders included International Atomic Energy Agency, World Meteorological Organization and the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization, which has radiation detection equipment deployed around the world.
The radiation effects from the Fukushima Daiichi nuclear disaster are the observed and predicted effects as a result of the release of radioactive isotopes from the Fukushima Daiichii Nuclear Power Plant following the 2011 Tōhoku 9.0 magnitude earthquake and tsunami. The release of radioactive isotopes from reactor containment vessels was a result of venting in order to reduce gaseous pressure, and the discharge of coolant water into the sea. This resulted in Japanese authorities implementing a 30-km exclusion zone around the power plant and the continued displacement of approximately 156,000 people as of early 2013. The number of evacuees has declined to 49,492 as of March 2018. Large quantities of radioactive particles from the incident, including iodine-131 and caesium-134/137, have since been detected around the world. Substantial levels have been seen in California and in the Pacific Ocean.
The Japanese reaction occurred after the Fukushima Daiichi nuclear disaster, following the 2011 Tōhoku earthquake and tsunami. A nuclear emergency was declared by the government of Japan on 11 March. Later Prime Minister Naoto Kan issued instructions that people within a 20 km (12 mi) zone around the Fukushima Daiichi nuclear plant must leave, and urged that those living between 20 km and 30 km from the site to stay indoors. The latter groups were also urged to evacuate on 25 March.
When the Fukushima Daiichi nuclear disaster began on 11 March 2011, reactor unit 4, 5 and 6 were all shut down. An explosion damaged unit 4 four days after the 2011 Tōhoku earthquake and tsunami. Damages from the earthquake and tsunami on unit 5 and 6 are relatively minor.
The Fukushima disaster cleanup is an ongoing attempt to limit radioactive contamination from the three nuclear reactors involved in the Fukushima Daiichi nuclear disaster that followed the earthquake and tsunami on 11 March 2011. The affected reactors were adjacent to one another and accident management was made much more difficult because of the number of simultaneous hazards concentrated in a small area. Failure of emergency power following the tsunami resulted in loss of coolant from each reactor, hydrogen explosions damaging the reactor buildings, and water draining from open-air spent fuel pools. Plant workers were put in the position of trying to cope simultaneously with core meltdowns at three reactors and exposed fuel pools at three units.
The Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company was formed June 7, 2011 by the Japanese government as an independent body to investigate the March Fukushima Daiichi nuclear disaster. The Investigation Committee issued an interim report in December 2011, and issued its final report in July 2012.
National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission or NAIIC is the commission to investigate the background and cause of Fukushima Daiichi nuclear disaster formed by the statutory law enactment by Diet of Japan on 7 October 2011 and started with the first commissioning meeting was held in Fukushima City, Fukushima Prefecture. The commission is scheduled to issue the report in six months on investigation and to propose the policy to reduce and prevent future accident and reduce damage on the nuclear power plant in Japan.
The Fukushima Daiichi nuclear disaster genshiryoku hatsudensho jiko) was a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011. It is the largest nuclear disaster since the Chernobyl disaster of 1986.
The Fukushima Daiichi nuclear disaster genshiryoku hatsudensho jiko) was a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011. It is the largest nuclear disaster since the Chernobyl disaster of 1986.
Unit 3 of the Fukushima Daiichi Nuclear Power Plant was one of the reactors in operation on 11 March 2011, when the plant was struck by the tsunami produced by the Tohoku earthquake. In the aftermath, the reactor experienced hydrogen gas explosions and suffered a partial meltdown, along with the other two reactors in operation at the time the tsunami struck, unit 1 and unit 2. Efforts to remove debris and coolant water contaminated with radiation are ongoing and expected to last several decades.
The Fukushima Daiichi nuclear accident genshiryoku hatsudensho jiko) was a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011. It was the largest nuclear disaster since the Chernobyl disaster of 1986, and the radiation released exceeded official safety guidelines. Despite this, there were no deaths caused by acute radiation syndrome. Given the uncertain health effects of low-dose radiation, cancer deaths cannot be ruled out. However, studies by the World Health Organisation and Tokyo University have shown that no discernible increase in the rate of cancer deaths is expected. Predicted future cancer deaths due to accumulated radiation exposures in the population living near Fukushima have ranged in the academic literature from none to hundreds.
The Fukushima Daiichi nuclear disaster genshiryoku hatsudensho jiko) was a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011. It is the largest nuclear disaster since the Chernobyl disaster of 1986.
Fukushima 50 is a 2020 Japanese disaster drama film directed by Setsurō Wakamatsu and written by Yōichi Maekawa. Starring Koichi Sato and Ken Watanabe, it is about the titular group of employees tasked with handling the meltdown of the Fukushima Daiichi Nuclear Power Plant after the 2011 Tōhoku earthquake and tsunami. The film is based on the book by Ryusho Kadota, titled On the Brink: The Inside Story of Fukushima Daiichi, and it is the first Japanese film to depict the disaster.
