Where is fukushima nuclear power plant

The safety limit set by the central government in mid-April for public recreation areas was 3. In June , analysis from Japan's Nuclear Regulation Authority NRA showed that the most contaminated areas in the Fukushima evacuation zone had reduced in size by three-quarters over the previous two years. In August The Act on Special Measures Concerning the Handling of Radioactive Pollution was enacted and it took full effect from January as the main legal instrument to deal with all remediation activities in the affected areas, as well as the management of materials removed as a result of those activities.

It specified two categories of land: Special Decontamination Areas consisting of the 'restricted areas' located within a 20 km radius from the Fukushima Daiichi plant, and 'deliberate evacuation areas' where the annual cumulative dose for individuals was anticipated to exceed 20 mSv.

The national government promotes decontamination in these areas. Intensive Contamination Survey Areas including the so-called Decontamination Implementation Areas, where an additional annual cumulative dose between 1 mSv and 20 mSv was estimated for individuals.

Municipalities implement decontamination activities in these areas. The doses to the general public, both those incurred during the first year and estimated for their lifetimes, are generally low or very low.

No discernible increased incidence of radiation-related health effects are expected among exposed members of the public or their descendants. However, the report noted: "More than additional workers received effective doses currently estimated to be over mSv, predominantly from external exposures. Among this group, an increased risk of cancer would be expected in the future.

However, any increased incidence of cancer in this group is expected to be indiscernible because of the difficulty of confirming such a small incidence against the normal statistical fluctuations in cancer incidence. These workers are individually monitored annually for potential late radiation-related health effects. By contrast, the public was exposed to times less radiation. Most Japanese people were exposed to additional radiation amounting to less than the typical natural background level of 2.

The Report states: "No adverse health effects among Fukushima residents have been documented that are directly attributable to radiation exposure from the Fukushima Daiichi nuclear plant accident. People living in Fukushima prefecture are expected to be exposed to around 10 mSv over their entire lifetimes, while for those living further away the dose would be 0.

The UNSCEAR conclusion reinforces the findings of several international reports to date, including one from the World Health Organization WHO that considered the health risk to the most exposed people possible: a postulated girl under one year of age living in Iitate or Namie that did not evacuate and continued life as normal for four months after the accident.

Such a child's theoretical risk of developing any cancer would be increased only marginally, according to the WHO's analysis. The man had been diagnosed with lung cancer in February Eleven municipalities in the former restricted zone or planned evacuation area, within 20 km of the plant or where annual cumulative radiation dose is greater than 20 mSv, are designated 'special decontamination areas', where decontamination work is being implemented by the government.

A further municipalities in eight prefectures, where dose rates are equivalent to over 1 mSv per year are classed as 'intensive decontamination survey areas', where decontamination is being implemented by each municipality with funding and technical support from the national government. Decontamination of all 11 special decontamination areas has been completed.

In October a member IAEA mission reported on remediation and decontamination in the special decontamination areas. Its preliminary report said that decontamination efforts were commendable but driven by unrealistic targets.

Also, there is potential to produce more food safely in contaminated areas. The total area under consideration for attention is 13, km 2. Summary : There have been no harmful effects from radiation on local people, nor any doses approaching harmful levels.

However, some , people were evacuated from their homes and only from were allowed limited return. As of July over 41, remained displaced due to government concern about radiological effects from the accident.

Permanent return remains a high priority, and the evacuation zone is being decontaminated where required and possible, so that evacuees can return.

There are many cases of evacuation stress including transfer trauma among evacuees, and once the situation had stabilized at the plant these outweighed the radiological hazards of returning, with deaths reported see below. The government said it would consider purchasing land and houses from residents of these areas if the evacuees wish to sell them.

In November the NRA decided to change the way radiation exposure was estimated. Instead of airborne surveys being the basis, personal dosimeters would be used, giving very much more accurate figures, often much less than airborne estimates. Measurement was by personal dosimeters over August-September Disaster-related deaths are in addition to the over 19, that died in the actual earthquake and tsunami.

The premature disaster-related deaths were mainly related to i physical and mental illness brought about by having to reside in shelters and the trauma of being forced to move from care settings and homes; and ii delays in obtaining needed medical support because of the enormous destruction caused by the earthquake and tsunami. However, the radiation levels in most of the evacuated areas were not greater than the natural radiation levels in high background areas elsewhere in the world where no adverse health effect is evident.

The figure is greater than for Iwate and Miyagi prefectures, with and respectively, though they had much higher loss of life in the earthquake and tsunami — over 14, 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.

As of July , over 41, people from Fukushima were still living as evacuees. The money was tax-exempt and paid unconditionally. In October , about 84, evacuees received the payments. The Fukushima prefecture had 17, government-financed temporary housing units for some 29, evacuees from the accident. The number compared with very few built in Miyagi, Iwate and Aomori prefectures for the , tsunami survivor refugees there.

In April , the first residents of Okuma, the closest town to the plant, were allowed to return home. According to a survey released by the prefectural government in April , the majority of people who voluntarily evacuated their homes after the accident and who are now living outside of Fukushima prefecture do not intend to return.

A Mainichi report said that Of the voluntary evacuees still living in Fukushima prefecture, An August Reconstruction Agency report also considered workers at Fukushima power plant. 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. Summary : Many evacuated people remain unable to fully return home due to government-mandated restrictions based on conservative radiation exposure criteria.

Decontamination work is proceeding while radiation levels decline naturally. Removing contaminated water from the reactor and turbine buildings had become the main challenge by week 3, along with contaminated water in trenches carrying cabling and pipework. This was both from the tsunami inundation and leakage from reactors. Run-off from the site into the sea was also carrying radionuclides well in excess of allowable levels.

By the end of March all storages around the four units — basically the main condenser units and condensate tanks — were largely full of contaminated water pumped from the buildings. Some storage tanks were set up progressively, including initially steel tanks with rubber seams, each holding m 3.

A few of these developed leaks in Accordingly, with government approval, Tepco over April released to the sea about 10, cubic metres of slightly contaminated water 0. Unit 2 is the main source of contaminated water, though some of it comes from drainage pits.

NISA confirmed that there was no significant change in radioactivity levels in the sea as a result of the 0. By the end of June , Tepco had installed concrete panels to seal the water intakes of units , preventing contaminated water leaking to the harbour.

From October, a steel water shield wall was built on the sea frontage of units It extends about one kilometre, and down to an impermeable layer beneath two permeable strata which potentially leak contaminated groundwater to the sea.

The inner harbour area which has some contamination is about 30 ha in area. In July-August only 0. Tepco built a new wastewater treatment facility to treat contaminated water. A supplementary and simpler SARRY simplified active water retrieve and recovery system plant to remove caesium using Japanese technology and made by Toshiba and The Shaw Group was installed and commissioned in August The NRA approved the extra capacity in August ALPS is a chemical system which will remove radionuclides to below legal limits for release.

However, because tritium is contained in water molecules, ALPS cannot remove it, which gives rise to questions about the discharge of treated water to the sea. Collected water from them, with high radioactivity levels, was being treated for caesium removal and re-used. Apart from this recirculating loop, the cumulative treated volume was then 1.

Almost m 3 of sludge from the water treatment was stored in shielded containers. ALPS-treated water is currently stored in tanks onsite which will reach full capacity by the summer of As of February , more than 1. Some of the ALPS treated water will require secondary processing to further reduce concentrations of radionuclides in line with government requirements.

Disposal will be either into the atmosphere or the sea. In November the trade and industry ministry stated that annual radiation levels from the release of the tritium-tainted water are estimated at between 0.

The clean tritiated water was the focus of attention in A September report from the Atomic Energy Society of Japan recommended diluting the ALPS-treated water with seawater and releasing it to the sea at the legal discharge concentration of 0. The WHO drinking water guideline is 0. The government had an expert task force considering the options. In April the Japanese government confirmed that the water would be released into the sea in This is fed through a catalytic exchange column with a little water which preferentially takes up the tritium.

It can be incorporated into concrete and disposed as low-level waste. The tritium is concentrated to 20, times. The MDS is the first system to be able economically to treat large volumes of water with low tritium concentrations, and builds on existing heavy water tritium removal systems. Each module treats up to litres per day. Earlier in a new Kurion strontium removal system was commissioned. This is mobile and can be moved around the tank groups to further clean up water which has been treated by ALPS.

Apart from the above-ground water treatment activity, there is now a groundwater bypass to reduce the groundwater level above the reactors by about 1. This prevents some of it flowing into the reactor basements and becoming contaminated.

In addition, an impermeable wall was constructed on the sea-side of the reactors, and inside this a frozen soil wall was created to further block water flow into the reactor buildings. In October guidelines for rainwater release from the site allowed Tepco to release water to the sea without specific NRA approval as long as it conformed to activity limits. Summary: A large amount of contaminated water has accumulated onsite and has been treated to remove radioactive elements, apart from tritium.

In April , the Japanese government confirmed that the water would be released into the sea. Some radioactivity has already been released to the sea, but this has mostly been low-level and it has not had any significant impact beyond the immediate plant structures. Concentrations outside these structures have been below regulatory levels since April In particular, proposals were sought for dealing with: the accumulation of contaminated water in storage tanks, etc ; the treatment of contaminated water including tritium removal; the removal of radioactive materials from the seawater in the plant's 30 ha harbour; the management of contaminated water inside the buildings; measures to block groundwater from flowing into the site; and, understanding the flow of groundwater.

Responses were submitted to the government in November. In December IRID called for innovative proposals for removing fuel debris from units about It works with IRID, whose focus now is on developing mid- and long-term decommissioning technologies. They were in 'cold shutdown' at the time, but still requiring pumped cooling.

They were restored to cold shutdown by the normal recirculating system on 20 March, and mains power was restored on March. In September Tepco commenced work to remove the fuel from unit 6. Prime minister Abe then called for Tepco to decommission both units. Tepco announced in December that it would decommission both units from the end of January They entered commercial operation in and respectively.

It is proposed that they will be used for training. Tepco published a six- to nine-month plan in April for dealing with the disabled Fukushima reactors, and updated this several times subsequently. Remediation over the first couple of years proceeded approximately as planned. In August Tepco announced its general plan for proceeding with removing fuel from the four units, initially from the spent fuel ponds and then from the actual reactors.

At the end of Tepco announced the establishment of an internal entity to focus on measures for decommissioning units and dealing with contaminated water. In June the government revised the decommissioning plan for the second time, though without major change.

It clarified milestones to accomplish preventive and multi-layered measures, involving the three principles of removing the source of the contamination, isolating groundwater from the contamination source, and preventing leakage of the contaminated water. It included a new goal of cutting the amount of groundwater flowing into the buildings to less than m 3 per day by April The schedule for fuel removal from the pond at unit 1 was postponed from late FY17 to FY20, while that for unit 2 was delayed from early FY20 to later the same fiscal year, and that at unit 3 from early FY15 to FY Fuel debris removal was to begin in , as before.

In September the government updated the June decommissioning roadmap, with no changes to the framework, and confirming first removal of fuel debris from unit 1 in Treatment of all contaminated water accumulated in the reactor buildings was to be completed by For unit 3, fuel removal was completed in February Fuel debris removal remains scheduled to begin in FY Tepco has a website giving updates on decommissioning work and environmental monitoring. Storage ponds : Debris has been removed from the upper parts of the reactor buildings using large cranes and heavy machinery.

Casks to transfer the removed fuel to the central spent fuel facility have been designed and manufactured using existing cask technology. In July two unused fuel assemblies were removed from unit 4 pond, and were found to be in good shape, with no deformation or corrosion. Tepco started removal of both fresh and used fuel from the pond in November , 22 assemblies at a time in each cask, with used and new ones to be moved. This was uneventful, and the task continued through By 22 December , all used as well as all new fuel assemblies had been moved in 71 cask shuttles without incident.

All of the radioactive used fuel was removed by early November, eliminating a significant radiological hazard on the site.

The used fuel went to the central storage pond, from which older assemblies were transferred to dry cask storage. The fresh fuel assemblies are stored in the pool of the undamaged unit 6. Tepco completed moving fuel from unit 3 in February It will now focus on used fuel assemblies and new ones from unit 1, and then used assemblies and 28 new ones from unit 2 will be transferred.

The NRA has expressed concern about the unit 1 used fuel. Reactors order of work : The locations of leaks from the primary containment vessels PCVs and reactor buildings should first be identified using manual and remotely controlled dosimeters, cameras, etc. Any leakage points will be repaired and both reactor vessels RPVs and PCVs filled with water sufficient to achieve shielding.

Then the vessel heads will be removed. The location of melted fuel and corium will then be established. In particular, the distribution of damaged fuel believed to have flowed out from the RPVs into PCVs will be ascertained, and it will be sampled and analysed. After examination of the inside of the reactors, states of the damaged fuel rods and reactor core internals, sampling will be done and the damaged core material will be removed from the RPVs as well as from the PCVs.

Updated plans are on the IRID website. The four reactors will be completely demolished in years — much the same timeframe as for any nuclear plant. Earlier, consortia led by both Hitachi-GE and Toshiba submitted proposals to Tepco for decommissioning units This would generally involve removing the fuel and then sealing the units for a further decade or two while the activation products in the steel of the reactor pressure vessels decay.

They can then be demolished. Removal of the very degraded fuel will be a long process in units , but will draw on experience at Three Mile Island in the USA. A member international expert team assembled by the IAEA at the request of the Japanese government carried out a fact-finding mission in October on remediation strategies for contaminated land.

Its report focused on the remediation of the affected areas outside of the 20 km restricted area. The team said that it agreed with the prioritization and the general strategy being implemented, but advised the government to focus on actual dose reduction.

They should "avoid over-conservatism" which "could not effectively contribute to the reduction of exposure doses" to people. It warned the government against being preoccupied with "contamination concentrations The four units at Fukushima Daini were shut down automatically due to the earthquake.

The tsunami — here only 9 m high — affected the generators and there was major interruption to cooling due to damaged heat exchangers, so the reactors were almost completely isolated from their ultimate heat sink. Damage to the diesel generators was limited and also the earthquake left one of the external power lines intact, avoiding a station blackout as at Daiichi units Staff laid and energized 8. Unit 3 was undamaged and continued to 'cold shutdown' status on the 12th, but the other units suffered flooding to pump rooms where the equipment transfers heat from the reactor heat removal circuit to the sea.

Pump motors were replaced in less than 30 hours. The almost complete loss of ultimate heat sink for a day proved a significant challenge, but the cores were kept fully covered. There was no technical reason for the Fukushima Daini plant not to restart. However, Tepco in October said it planned to transfer the fuel from the four reactors to used fuel ponds, and this was done. In February the prime minister said that restarting the four units was essentially a matter for Tepco to decide.

While authorities are engaged in ongoing efforts to decontaminate the land, some areas remain inaccessible. More than people died as a result of the nuclear accident, including some whose deaths resulted from the prolonged evacuation. Among survivors, many lost the foundation of their lives. Meanwhile, the accident is not over. The Fukushima Daiichi Nuclear Power Station remains contaminated with difficult-to-remove fuel debris.

Also, the accident site continues to generate contaminated water. The molten core that reached the bottom of the containment vessel during the disaster later solidified into fuel debris. This debris contains fission products that emit radiation strong enough to cause death after a few hours of exposure. As a result, cleanup work is performed by remote control.

Though the Tokyo Electric Power Company plans to develop technology and remove the fuel debris in upcoming decades, some nuclear engineers doubt that the core can be removed. Since the fuel debris continues to generate heat, water is still circulated to cool the reactor buildings. This circulating water is exposed to debris, leaving it contaminated.

This contaminated, circulating water later mixes with groundwater flowing into the reactor buildings. Without intervention, this process would have led to large-scale groundwater pollution. Instead, the power company installed a wall in the ground around the building to limit the inflow of groundwater. Also, though part of the incoming groundwater is purified, the water remains radioactive with tritium. For this reason, the water is stored on site in tanks. Though tanks for this radioactive water cover the ground tightly on the site, the power company is considering diluting the water and releasing it into the ocean.

Needless to say, local fishermen and others strongly oppose the release. Even before the accident, the regulators and the regulated appeared to be on the same side, which had a negative impact on regulation.

After the accident, the investigation committee pointed out that the old regulation authority had not applied the latest knowledge concerning natural disasters such as earthquakes and tsunamis and that severe accident countermeasures had not been taken. The Nuclear Regulation Authority has begun a nuclear conformity assessment based on the new standards. Under the new requirements, the Nuclear Regulation Authority incorporates severe accident countermeasures that were not previously required.

Also, they will pay particular attention to natural disasters such as earthquakes and tsunamis that could cause internal fires or flooding. They will also work to diversify safety facilities and plan for anti-terrorism measures.

To date, the regulation authority and the electric power company have met in nearly 1, review meetings. Their meeting records reveal some of the problems at the restarted nuclear power plants, particularly with boiling water reactors that caused the Fukushima accident.

Prior to the Fukushima accident, regulators and plant operators did not understand the importance of vents—the intentional release of radioactive gas from a containment vessel—for accident response measures. However, those who conducted the conformity review learned lessons about venting from the Fukushima accident.

There are two types of vents: filter vents and hardened vents. As mentioned above, the relatively small volume of the boiling water reactor containment vessel poses a risk when internal pressure rises during an accident. Though a suppression chamber is intended to provide backup, this also failed during the Fukushima accident. In the conformity review, the Nuclear Regulation Authority mandated installing a new cooling system to compensate for this flaw.

In this system, water is removed from the suppression chamber, passed through an additional heat exchanger to lower the temperature, and then returned to the containment vessel.

However, since virtually all severe boiling water reactor accidents result from a failure to remove decay heat, this type of reactor may have a design flaw. In light of this, the Nuclear Regulation Authority should have addressed the design flaw rather than allowing plants to restart with alternative circulation cooling systems. However, recombiners remove only a relatively small amount of hydrogen which is generated during normal operation.

Researchers have not demonstrated that recombiners can remove a large amount of hydrogen generated during a nuclear accident—and many doubt this is possible.

In the event of a severe accident, the Nuclear Regulation Authority relies on mobile safety facilities, including a large number of water injection vehicles, power supply vehicles, and more. But is this realistic in the event of an earthquake?

Water pumped into the ruined reactors at the Fukushima plant to cool the melted fuel, mixed with rain and groundwater that has also been contaminated, is being treated using an advanced liquid processing system, or ALPS.

The process removes most radioactive materials including strontium and cesium but leaves behind tritium, which is related to hydrogen and said to pose little health risk in low concentrations. The water is being kept in tanks on the plant's premises, and there was about 1.

TEPCO expects to run out of storage capacity as early as fall next year, and the government had been considering ways to dispose of the water. The government's plan calls for TEPCO to pay compensation to local fishermen who suffer reputational damage, though it does not detail how that determination will be made.

The head of the national federation of fisheries cooperatives, Hiroshi Kishi, strongly opposed the decision to release the tritiated water into the sea, calling it "utterly unacceptable" and saying it "tramples on the feelings of fishermen not only in Fukushima Prefecture but across Japan.

China's Foreign Ministry said in a statement the decision is "extremely irresponsible" and detrimental for neighboring countries, while Taiwan's Atomic Energy Council also voiced opposition. The South Korean government held an emergency meeting to discuss its response, with the Foreign Ministry summoning Japanese Ambassador Koichi Aiboshi to lodge a formal protest.

China, Taiwan and South Korea are among 15 countries and regions that continue to restrict imports of Japanese agricultural and fishery products following the Fukushima disaster.

Meanwhile, the International Atomic Energy Agency backed the plan to release the water into the Pacific Ocean, with Director General Rafael Grossi saying the method is "both technically feasible and in line with international practice.

Following the announcement, the U. State Department noted that Japan has "weighed the options and effects, has been transparent about its decision, and appears to have adopted an approach in accordance with globally accepted nuclear safety standards. According to the government's plan, the tritium will be diluted to less than 1, becquerels per liter, oneth of the concentration permitted under Japanese safety standards and one-seventh of the World Health Organization's guideline for drinking water.

A subcommittee of Japan's Ministry of Economy, Trade and Industry concluded in February that releasing the tritiated water into the sea and evaporating it were both realistic options, with the former being easier for monitoring radiation levels. The government had initially hoped to finalize the decision last October, viewing it as necessary to clear up space at the Fukushima plant in order to move forward with the decades-long decommissioning process, but decided it needed more time to gain the public's understanding.