In the areas where the orders have been lifted, the number of residents returning to their homes is gradually increasing. According to a Fukushima Prefectural Government summary, as of March 5 this year, the number of deaths in the prefecture due to the earthquake disaster, including related fatalities, was 4, By municipality, Minamisoma had the highest number of deaths with 1,, followed by Namie with , Soma with , Tomioka with , and Iwaki with Of these, 2, were certified as disaster-related deaths, an increase of 16 over the past year.
This is mainly due to natural processes such as rainfall washing away surface contamination and the natural turning-over of soil and vegetation.
Remediation efforts by the Japanese government have accelerated the process by removing topsoil from more affected areas. Okuma Town has supported the process of stabilising and now decommissioning the power plant by hosting a meal service centre to feed the many thousands of workers who have rotated through the Fukushima Daiichi site. A research centre has also been built there to study solid radioactive wastes, develop methods to analyse certain hard-to-measure radionuclides and to develop technology to treat and dispose of the fuel debris from the accident.
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.
In July Tepco announced its decision to decommission the four reactors. The sequence of events relating to the fuel pond at unit 4 was rated INES level 3 — a serious incident. However, a month after the tsunami the NSC raised the rating to level 7 for units together, 'a major accident', saying that a re-evaluation of early radioactive releases suggested that some PBq of I equivalent had been discharged, mostly in the first week.
This then matched the criterion for level 7. Beyond whatever insurance Tepco might carry for its reactors is the question of third party liability for the accident. Japan was not party to any international liability convention but its law generally conforms to them, notably strict and exclusive liability for the operator.
In mid-April , the first meeting was held of a panel to address compensation for nuclear-related damage. The panel established guidelines for determining the scope of compensation for damage caused by the accident, and to act as an intermediary.
On 11 May , Tepco accepted terms established by the Japanese government for state support to compensate those affected by the accident at the Fukushima Daiichi plant. The scheme included a new state-backed institution to expedite payments to those affected by the Fukushima Daiichi accident.
The body receives financial contributions from electric power companies with nuclear power plants in Japan, and from the government through special bonds that can be cashed whenever necessary. Tepco accepted the conditions imposed on the company as part of the package. That included not setting an upper limit on compensation payments to those affected, making maximum efforts to reduce costs, and an agreement to cooperate with an independent panel set up to investigate its management.
This Nuclear Damage Compensation Facilitation Corporation, established by government and nuclear plant operators, includes representatives from other nuclear generators and also operates as an insurer for the industry, being responsible to have plans in place for any future nuclear accidents. The provision for contributions from other nuclear operators is similar to that in the USA. The government estimates that Tepco will be able to complete its repayments in 10 to 13 years, after which it will revert to a fully private company with no government involvement.
Meanwhile it will pay an annual fee for the government support, maintain adequate power supplies and ensure plant safety. On 14 June , Japan's cabinet passed the Nuclear Disaster Compensation Bill, and a related budget to fund post-tsunami reconstruction was also passed subsequently.
In September the Nuclear Damage Compensation Facilitation Corporation started by working with Tepco to compile a business plan for the next decade. In June shareholders voted to sell the Japanese government Or, if you are already a subscriber Sign in. Other options. Close drawer menu Financial Times International Edition. Search the FT Search. World Show more World. US Show more US.
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