The plan also involved Tepco reducing its own costs by JPY 2545 billion ($32.6 billion) over the next ten years, including shedding 7400 jobs. There was some use of built-in plumbing for unit 2. A massive national project to remove topsoil and vegetation contaminated by the Fukushima nuclear disaster will produce at least 22 million … Japan has poured billions of dollars into recovery from the 2011 Fukushima nuclear disaster. They were in 'cold shutdown' at the time, but still requiring pumped cooling. Initially cooling would have been maintained through the main steam circuit bypassing the turbine and going through the condensers. In June 2015, 108 m3/day of clean water was being circulated through each reactor (1-3). However, some 160,000 people were evacuated from their homes and only from 2012 were allowed limited return. Apart from this recirculating loop, the cumulative treated volume was then 1.232 million cubic metres. The main source of radioactive releases was the apparent hydrogen explosion in the suppression chamber of unit 2 on 15 March. At that time the explosion was thought to have damaged the containment vessel housing the fuel rods. Permanent return remains a high priority, and the evacuation zone is being decontaminated where required and possible, so that evacuees (81,000 from this accident according to METI) can return without undue delay. Without heat removal by circulation to an outside heat exchanger, this produced a lot of steam in the reactor pressure vessels housing the cores, and this was released into the dry primary containment (PCV) through safety valves. An August 2012 Reconstruction Agency report also considered workers at Fukushima power plant. Tepco has not announced any decision about whether to retire or move towards restarting the four units. (Japan Times 20/2/14), Evacuees receive JPY 100,000 (about $1000) per month in psychological suffering compensation. The operating units which shut down were Tokyo Electric Power Company's (Tepco) Fukushima Daiichi 1, 2, 3, and Fukushima Daini 1, 2, 3, 4, Tohoku's Onagawa 1, 2, 3, and Japco's Tokai, total 9377 MWe net. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Two of the damaged containment buildings at the Fukushima Daiichi nuclear power plant, northeastern Fukushima prefecture, Japan, several days after the March 11, 2011, earthquake and tsunami that crippled the installation. The Fukushima nuclear disaster's legacy: An inescapable stigma Two years ago, Tepco erected a dome over the Unit 3 reactor and fuel pool so that engineers could bring in … In addition, an impermeable wall is being constructed on the sea-side of the reactors, and inside this a frozen soil wall will further block water flow into the reactor buildings. Local government is in favour of decommissioning. Registered office: Tower House, 10 Southampton Street, London, WC2E 7HA, United Kingdom, Reuse of World Nuclear Association Content, Earthquakes and Seismic Protection for Nuclear Power Plants in Japan, Fukushima Nuclear Accident Independent Investigation Commission, http://www.reconstruction.go.jp/topics/20121102_sinsaikanrensi.pdf, http://www.reconstruction.go.jp/topics/240821_higashinihondaishinsainiokerushinsaikanrenshinikansuruhoukoku.pdf, National Diet Investigation Commission report, Fukushima Daiichi Accident – Technical Causal Factor Analysis, Government’s Decision on Addressing the Contaminated Water Issue at TEPCO’s Fukushima Daiichi NPS, The Fukushima-Daiichi nuclear power plant accident, Report by the Director General on The Fukushima Daiichi Accident, Earthquakes and Seismic Protection for Japanese Nuclear Power Plants, Nuclear Energy and Sustainable Development, Hydrogen explosion (not confirmed for unit 2). The tsunami countermeasures taken when Fukushima Daiichi was designed and sited in the 1960s were considered acceptable in relation to the scientific knowledge then, with low recorded run-up heights for that particular coastline. Summary: Major fuel melting occurred early on in all three units, though the fuel remains essentially contained except for some volatile fission products vented early on, or released from unit 2 in mid-March, and some soluble ones which were leaking with the water, especially from unit 2, where the containment is evidently breached. Maps from MEXT aerial surveys carried out approximately one year apart show the reduction in contamination from late 2011 to late 2012. The total area under consideration for attention is 13,000 km2. The results of UNSCEAR’s 12-month study on the magnitude of radioactive releases to the atmosphere and ocean, and the range of radiation doses received by the public and workers were announced in May 2013 are reported above in the subsection on Radiation Exposure. The tritium is concentrated 1000 to 20,000 times. Updates? Each of six trains is capable of processing 250 m3/day to remove 62 remaining radioisotopes. Continuous questioning and openness to learning from experience are key to safety culture and are essential for everyone involved in nuclear power.". The panel set up four teams to undertake investigations on the causes of the accident and ensuing damage and on measures to prevent the further spread of damage caused by the accident, but not to pursue the question of responsibility for the accident. In 2011, a tsunami led to a catastrophic nuclear disaster on Japan's Fukushima coast. These plants reduce caesium from about 55 MBq/L to 5.5 kBq/L – about ten times better than designed. Water injection commenced, using the various systems provide for this and finally the Emergency Core Cooling System (ECCS). Treatment using ALPS is ongoing at about 210 m3/day. A preliminary report from the World Health Organisation (WHO) in May 2012 estimated the radiation doses that residents of Japan outside the evacuated areas received in the year following the accident. Tepco figures submitted to NRA for the period to end January 2014 showed 173 workers had received more than 100 mSv (six more than two years earlier) and 1578 had received 50 to 100 mSv. Early in 2015 Japan ratified the Convention on Supplementary Compensation for Nuclear Damage (CSC). Meanwhile it will pay an annual fee for the government support, maintain adequate power supplies and ensure plant safety. Also, there is potential to produce more food safely in contaminated areas. On March 11, 2011, a 9.0-magnitude earthquake struck Japan about 231 miles (372 kilometers) northeast of Tokyo off the Honshu Island coast. In mid-2013 the Nuclear Regulation Authority (NRA) confirmed that the earthquake itself had caused no damage to unit 1. The government has allocated ¥1150 billion ($15 billion) for decontamination in the region, with the promise of more if needed. Such a child's theoretical risk of developing any cancer would be increased only marginally, according to WHO's analysis. From 2018 Tepco expects to move 514 used fuel assemblies from unit 3 to the central pool, as well as 52 new ones and then 292 used fuel assemblies and 100 new ones from unit 1. A 2016 study on the effects of the accident on fish and marine products showed that the contamination level had decreased dramatically over time, though the radioactivity of some species, especially sedentary rockfish, remained elevated within the exclusion zone. Animation video of the process here. Event sequence following earthquake (timing from it: 14:46, 11 March). K. Tateiwa, Jan 2014, Decommissioning Fukushima Daiichi NPS Causes of indirect deaths include physical and mental stress stemming from long stays at shelters, a lack of initial care as a result of hospitals being disabled by the disaster, and suicides. Unit 3 had battery power for about 30 hours. Its preliminary report said that decontamination efforts were commendable but driven by unrealistic targets. Though the Fukushima Nuclear Power Plant escaped the earthquakethat occured in the Tōhoku region, it was near the Pacific Ocean and thus, was severely hit by the Tōhoku tsunami, which was a direct result of the earthquake. Tenth reactor to restart in Japan following Fukushima disaster shutdown. Reactor capacity is 460 MWe for unit 1, 784 MWe for units 2-5, and 1100 MWe for unit 6. However, this resulted in radioactive releases to the environment. Early in 2014 the government estimated it would take JPY11 trillion and 40 years to clean up the Fukushima site. The ponds hold some fresh fuel and some used fuel, the latter pending its transfer to the central used/spent fuel storage on site. It included a new goal of cutting the amount of groundwater flowing into the buildings to less than 100 m3 per day by April 2016. It was not until the middle of December 2011 that Japanese Prime Minister Noda Yoshihiko declared the facility stable, after the cold shutdown of the reactors was completed. Unit 2 is the main source of contaminated water, though some of it comes from drainage pits. In January 2012 it was reported that an industry consortium (Hitachi GE Nuclear Energy, Mitsubishi Heavy Industries and Toshiba) would determine how to locate fuel debris inside units 1-3 and how to fill the pressure vessels with water. Although all three of the reactors that were operating were successfully shut down, the loss of power caused cooling systems to fail in each of them within the first few days of the disaster. Unit 3 was undamaged and continued to 'cold shutdown' status on 12th, but the other units suffered flooding to pump rooms where the equipment transfers heat from the reactor heat removal circuit to the sea. Developments since the 2013 UNSCEAR Report on the levels and effects of radiation exposure due to the nuclear accident following the great east-Japan earthquake and tsunami - UNSCEAR White Paper, 2015 The Fukushima Daiichi Accident - IAEA, 2015 The other three, at Fukushima Daiichi, lost power at 3.42 pm, almost an hour after the earthquake, when the entire site was flooded by the 15-metre tsunami. Fuel debris removal was to begin in 2021, as before. Measurement was by personal dosimeters over August-September 2012. In October 2013 a 16-member IAEA mission visited at government request and reported on remediation and decontamination in particular. Tepco has written off the four reactors damaged by the accident, and is decommissioning them. 15:42 TEPCO made the first emergency report to the government. Meanwhile a July 2011 report from MIT's Centre for Advanced Nuclear Energy Systems provided a useful series of observations, questions raised, and suggestions. The used fuel went to the central storage pond, from which older assemblies were transferred to dry cask storage – 1004 moved since the accident by mid 2014 to make way for new inputs from unit 4. Due to volatile and easily-airborne fission products being carried with the hydrogen and steam, the venting and hydrogen explosions discharged a lot of radioactive material into the atmosphere, notably iodine and caesium. There were up to 200 workers on site each day. The Japanese government plans to start preparations in 2020 for the disposal of the contaminated water. Tokyo’s Board of Audit reported in October 2013 that 23% of recovery funding – about JPY 1.45 trillion ($14.5 billion) – had been misappropriated. TEPCO officials reported that tsunami waves generated by the main shock of the Japan earthquake on March 11, 2011, damaged the backup generators at the Fukushima Daiichi plant. After about three years under water, used fuel can be transferred to dry storage, with air ventilation simply by convection. Let us know if you have suggestions to improve this article (requires login). Some $16 billion of this was distributed evenly among 85,000 evacuees – $188,200 each person including children, as directed early in 2011. Tests on radioactivity in rice have been made and caesium was found in a few of them. The three units lost the ability to maintain proper reactor cooling and water circulation functions. 21:23 The government ordered 3km evacuation and to keep staying inside buildings in the area of 3-10km radius. This Nuclear Damage Compensation Facilitation Corporation, established by government and nuclear plant operators, includes representatives from other nuclear generators and will also operate as an insurer for the industry, being responsible to have plans in place for any future nuclear accidents. Plans and procedures for venting and manual operation of emergency cooling were incomplete and their implementation in emergency circumstances proved very difficult as a result. In May 2013, the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported, following a detailed study by 80 international experts. The death toll directly due to the nuclear accident or radiation exposure remained zero, but stress and disruption due to the continuing evacuation remains high. The International Research Institute for Nuclear Decommissioning (IRID) was set up in August 2013 Japan by JAEA, Japanese utilities and reactor vendors, with a focus on Fukushima 1-4. Restrictions were placed on the distribution and consumption of food and the consumption of drinking water. Analysis of water has confirmed that most fuel rods are intact. The same criteria would be used, as above, with 20 mSv/yr being the threshold of concern to authorities. Three Tepco employees at the Daiichi and Daini plants were killed directly by the earthquake and tsunami, but there have been no fatalities from the nuclear accident. The dry storage area held 408 fuel assemblies at the time of the accident, and 1004 have been transferred there since (to mid-2014). High radiation levels in the three reactor buildings has hindered access there. In Unit 3, the main back-up water injection system failed at about 11 am on Saturday 12th and early on Sunday 13th, water injection using the high pressure system failed also and water levels dropped dramatically. For Fukushima Daini, NISA declared INES Level 3 for units 1, 2, 4 – each a serious incident. Considerable work was done to reduce the amount of radioactive debris on site and to stabilise dust. The government said it would consider purchasing land and houses from residents of these areas if the evacuees wish to sell them. In December 2013 the government raised the upper limit of its financial assistance to Tepco from JPY 5 trillion to JPY 9 trillion ($86 billion). However, subsequent inspection of the suppression chamber did not support the rupture interpretation. In 2002 the design basis was revised to 5.7 metres above, and the seawater pumps were sealed. The investment is expected to be JPY 300 billion ($3 billion). The fuel handling machine for unit 3 was built by Toshiba in January 2016 and delivered to the port at the plant. Media reports have referred to "nuclear gypsies" – casual workers employed by subcontractors on a short-term basis, and allegedly prone to receiving higher and unsupervised radiation doses. In December 2011 the government said that where annual radiation dose would be below 20 mSv/yr, the government would help residents return home as soon as possible and assist local municipalities with decontamination and repair of infrastructure. The four reactors will be completely demolished in 30-40 years – much the same timeframe as for any nuclear plant. Thereafter, many weeks of focused work centred on restoring heat removal from the reactors and coping with overheated spent fuel ponds. Workers continue to struggle with the disaster at the Fukushima Daiichi Nuclear Power Plant, caused by the earthquake and tsunami on March 11, 2011. This, it said, also resulted from "harmful rumours" about the possible health effects of consuming food products from the region near the damaged power plant. Fukushima Dai-ichi lost all power from the electric grid, with diesel generators providing power for about 40 minutes. They should "avoid over-conservatism" which "could not effectively contribute to the reduction of exposure doses" to people. The panel established guidelines for determining the scope of compensation for damage caused by the accident, and to act as an intermediary. By March 2016 total decay heat in units 1-3 had dropped to 1 MW for all three, about 1% of the original level, meaning that cooling water injection – then 100 m3/d – could be interrupted for up to two days. Most Japanese people were exposed to additional radiation amounting to less than the typical natural background level of 2.1 mSv per year. The maximum amplitude of this tsunami was 23 metres at point of origin, about 180 km from Fukushima. Later this was accompanied by hydrogen, produced by the interaction of the fuel's very hot zirconium cladding with steam after the water level dropped. The resultant earthquake was the largest in Japan's history. In April 2012 the US Electric Power Research Institute (EPRI) published Fukushima Daiichi Accident – Technical Causal Factor Analysis, which identified the root cause beyond the flooding and its effects as a failure to consider the possibility of the rupture of combinations of geological fault segments in the vicinity of the plant. Initially this was attempted with fire pumps but from 22 March a concrete pump with 58-metre boom enabled more precise targeting of water through the damaged walls of the service floors. Intensive Contamination Survey Areas including the so-called Decontamination Implementation Areas, where an additional annual cumulative dose between 1mSv and 20mSv was estimated for individuals. Tepco management ignored an instruction from the prime minister to cease the seawater injection into unit 1, and this instruction was withdrawn shortly afterwards. This 97-page report gives a valuable and detailed account of events. Inside unit 1, it is understood that the water level dropped to the top of the fuel about three hours after the scram (about 6 pm) and the bottom of the fuel 1.5 hours later (7.30 pm). Its Appendix has some constructive comment on radiation exposure and balancing the costs of dose avoidance in circumstances of environmental contamination. This assumption was accepted by nuclear power plant operators and was not challenged by regulators or by the government. They can then be demolished. 20 mSv/yr was also the general limit set for children's dose rate related to outdoor activities, but there were calls to reduce this.In areas with 20-50 mSv/yr from April 2012 residency is restricted, with remediation action taken. This was both from the tsunami inundation and leakage from reactors. They were restored to cold shutdown by the normal recirculating system on 20th, and mains power was restored on 21-22nd. Any leakage points will be repaired and both reactor vessels (RPVs) and PCVs filled with water sufficient to achieve shielding. It also summarised radioactive releases and their effects. In 2012 the Japanese standard for caesium in food supply was dropped from 500 to 100 Bq/kg. However, since they are leaking, the normal definition of "cold shutdown" does not apply, and Tepco waited to bring radioactive releases under control before declaring "cold shutdown condition" in mid-December, with NISA's approval. There is no technical reason for the Fukushima Daini plant not to restart. This is 69 x 31 m cover (53 m high) and it was fully equipped by the end of 2013 to enable unloading of used fuel from the storage pond into casks, each holding 22 fuel assemblies, and removal of the casks. In September 2013 Tepco commenced work to remove the fuel from unit 6. At the IAEA General Conference in 2012 the Director General promised a comprehensive report which would be "an authoritative, factual and balanced assessment, addressing the causes and consequences of the accident as well as the lessons learned." There are fuel ponds near the top of all six reactor buildings at the Daiichi plant, adjacent to the top of each reactor so that the fuel can be unloaded under water when the top is off the reactor pressure vessel and it is flooded. 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