WE ADMIRED THE JAPANESE ____ THE CITY OF FUKUSHIMA DAIICHI ACCIDENT

chọn lớp tất cả Mẫu giáo Lớp 1 Lớp 2 Lớp 3 Lớp 4 Lớp 5 Lớp 6 Lớp 7 Lớp 8 Lớp 9 Lớp 10 Lớp 11 Lớp 12 ĐH - CĐ
lựa chọn môn toàn bộ Toán trang bị lý Hóa học viên học Ngữ văn giờ anh lịch sử vẻ vang Địa lý Tin học technology Giáo dục công dân Âm nhạc thẩm mỹ Tiếng anh thí điểm lịch sử dân tộc và Địa lý thể thao Khoa học tự nhiên và thôn hội Đạo đức thủ công bằng tay Quốc phòng an toàn Tiếng việt Khoa học tự nhiên và thoải mái
tất cả Toán đồ dùng lý Hóa học sinh học Ngữ văn giờ anh lịch sử dân tộc Địa lý Tin học công nghệ Giáo dục công dân Âm nhạc thẩm mỹ Tiếng anh thí điểm lịch sử dân tộc và Địa lý thể dục thể thao Khoa học tự nhiên và làng mạc hội Đạo đức bằng tay thủ công Quốc phòng an toàn Tiếng việt Khoa học thoải mái và tự nhiên

Choose A, B, C, or D that best completes each sentence. We admired the Japanese _______ the đô thị of Fukushima after the disaster.

Bạn đang xem: Fukushima daiichi accident

A.To rebuild

B.Of having rebuilt

C.To being rebuilt

D.For having rebuilt

Đáp án:

Cấu trúc: admire sb for having + V.p.p: thương yêu ai vày đã có tác dụng điều gì đó

=> We admired the Japanese for having rebuilt the city of Fukushima after the disaster.

trợ thì dịch: chúng ta ngưỡng mộ tín đồ Nhật do đã xuất bản lại được tp Fukushima sau thảm họa.

Đáp án yêu cầu chọn là: D

Dưới đây là một vài thắc mắc có thể liên quan tới câu hỏi mà bạn gửi lên. Có thể trong đó bao gồm câu trả lời mà các bạn cần!
Choose A, B, C, or D that best completes each sentence. Question: The principal of a special school for the disabled said that the school has no _______ lớn replace broken hearing aids. A.sum B.fund C.collection...

Choose A, B, C, or D that best completes each sentence.

Question: The principal of a special school for the disabled said that the school has no _______ lớn replace broken hearing aids.

A.sum

B.fund

C.collection

D.availability

Đáp án:

sum (n): tổng

fund (n): quỹ

collection (n): thu thập

availability (n): tính sẵn sàng

=> The principal of a special school for the disabled said that the school has nofundto replace broken hearing aids.

Tạm dịch:Hiệu trưởng của một trường đặc biệt quan trọng dành cho người khuyết tật bảo rằng trường không tồn tại quỹ để thay thế các sản phẩm trợ thính bị hỏng.

Đáp án phải chọn là:B

Choose A, B, C, or D that best completes each sentence. Whey protein may account for many of the health benefits _____ lớn dairy products.

A.Believed

B.Attributed

C.Resulted

D.responsible

Đáp án: B

believed (v): tin tưởng

be attributed to (v): quy là, cho là

resulted in/ from (v): kết quả

be responsible for (adj): chịu đựng trách nhiệm

=> Whey protein may trương mục for many of the health benefitsattributedto dairy products.

Tạm dịch:Sản phẩm được làm từ sữa rất có thể chiếm nhiều ích lợi sức khỏe được hiểu trong các thành phầm hàng ngày.

Choose A, B, C, or D that best completes each sentence._____one kết thúc of the rope to his bed, he threw the other end out of the window.

A.Tie

B.Tied

C.Tying

D.Having tied

Đáp án: D

Khi một hành vi xảy ra trước một hành động khác trong vượt khứ, hai hành động có cùng nhà ngữ, thì hành vi xảy ra trước được phân chia về phân từ hoàn thành.

Cấu trúc: having + V.p.p

=>Having tiedone end of the rope lớn his bed, he threw the other end out of the window.

Tạm dịch: sau khoản thời gian cột một đầu dây vào giường, anh ta ném đầu kia thoát ra khỏi cửa sổ.

Choose A, B, C, or D that best completes each sentence. The UK offers a wide range of work-based ________ for students seeking to build careers in specific industries.

A.Learning

B.Training

C.Exercising

D.competition

Đáp án: B

learning (n): câu hỏi học

training (n): đào tạo và huấn luyện

exercising (n): việc rèn luyện

competition (n): cuộc thi

=> The UK offers a wide range of work-based training for students seeking to build careers in specific industries.

trợ thời dịch: vương quốc Anh hỗ trợ một loạt những khóa đào tạo và giảng dạy dựa trên kiếm tìm kiếm nhằm xây dựng nghề nghiệp và công việc trong những ngành công nghiệp cụ thể.

Choose A, B, C, or D that best completes each sentence. Question: The boy_____ his sight due to lớn the accident at the age of nine. A.loses B.lost C.has lost D.was...

Choose A, B, C, or D that best completes each sentence.

Question: The boy_____ his sight due khổng lồ the accident at the age of nine.

A.loses

B.lost

C.has lost

D.was losing

Đáp án:

Trạng từ bỏ chỉ thời gian: “at the age of nine” (vào cơ hội 9 tuổi) chỉ thời điểm ở quá khứ

Cấu trúc: S + Ved/ V2

=>The boylosthis sight due lớn the accident at the age of nine.

Tạm dịch:Cậu bé bỏng đã khiếm thị cũng chính vì vụ tai nạn vào tầm khoảng 9 tuổi.

Đáp án nên chọn là:B

Choose A, B, C, or D that best completes each sentence. _______ the desalination plant, the company could offer an effective solution to lớn the problem of water scarcity.

A.To build

B.Having built

C.Being built

D.Having been built

Đáp án:

Hành cồn “see” nói về nguyên nhân cho hành động trong mệnh đề chính (the company could offer…) nên sử dụng phân từ trả thành.

Ở phía trên mệnh đề được sử dụng ở thể công ty động.

=> Having built the desalination plant, the company could offer an effective solution to lớn the problem of water scarcity.

lâm thời dịch: Nhờ tạo được xí nghiệp sản xuất khử muối, công ty đã rất có thể cung cấp một phương án hiệu trái cho sự việc khan hãn hữu nước.

Đáp án buộc phải chọn là: B

Choose A, B, C, or D that best completes each sentence. Northwestern became one of the first institutions to lớn establish a__________of e-commerce degree in the fall of 2000.

A.Diploma

B.Faculty

C.Institution

D.bachelor

Đáp án:

diploma (n): bởi cấp, văn bằng

faculty (n): khoa (của 1 trường đại học)

institution (n): viện, trường đại học

bachelor (n): bằng cử nhân

=> Northwestern became one of the first institutions lớn establish a bachelor of e-commerce degree in the fall of 2000.

nhất thời dịch: Northwestern trở thành trong những trường đại học đầu tiên cấp bằng cử nhân dịch vụ thương mại điện tử vào mùa thu năm 2000.

Đáp án bắt buộc chọn là: D

Choose A, B, C, or D that best completes each sentence. The full college status was only received in 1948 và marked the official _____ of women lớn the university.

A.Admit

B.Admittance

C.Admission

D.atmitting

Đáp án:

admit (v): nhấn vào

admittance (n): sự cho phép đi vào

admission (n): được trao vào ở 1 ngôi trường

=> The full college status was only received in 1948 and marked the official admission of women to lớn the university.

lâm thời dịch: giáo dục và đào tạo bậc đh cho toàn bộ mọi tín đồ chỉ được ghi nhận cho tới năm 1948 và bao gồm thức lưu lại sự tiếp nhận phụ thanh nữ vào học đại học.

Đáp án buộc phải chọn là: C

Choose A, B, C, or D that best completes each sentence. The public praised the local farmers for _______ millions of trees on the surrounding hills.

A.Plant

B.Being planted

C.Being planting

D.Having planted

Đáp án:

Cấu trúc: praise sb for having + V.p.p: ca ngợi ai do đã có tác dụng điều gì đó

=> The public praised the local farmers for having planned millions of trees on the surrounding hills.

tạm bợ dịch: Công chúng ca ngợi những tín đồ nông dân địa phương do đã trồng mặt hàng triệu cây xanh trên rất nhiều ngọn đồi xung quanh.

Đáp án đề xuất chọn là: D

tất cả Toán đồ dùng lý Hóa học sinh học Ngữ văn giờ đồng hồ anh lịch sử vẻ vang Địa lý Tin học công nghệ Giáo dục công dân Âm nhạc mỹ thuật Tiếng anh thí điểm lịch sử dân tộc và Địa lý thể dục Khoa học tự nhiên và xã hội Đạo đức bằng tay Quốc phòng an toàn Tiếng việt Khoa học thoải mái và tự nhiên
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Fukushima Daiichi Accident

(Updated January 2023)

Following a major earthquake, a 15-metre tsunami disabled the power nguồn supply & cooling of three Fukushima Daiichi reactors, causing a nuclear accident beginning on 11 March 2011. All three cores largely melted in the first three days.The accident was rated cấp độ 7 on the International Nuclear và Radiological sự kiện Scale, due khổng lồ high radioactive releases over days 4 khổng lồ 6, eventually a total of some 940 PBq (I-131 eq).All four Fukushima Daiichi reactors were written off due khổng lồ damage in the accident – 2719 MWe net.After two weeks, the three reactors (units 1-3) were stable with water addition and by July they were being cooled with recycled water from the new treatment plant. Official 'cold shutdown condition' was announced in mid-December.Apart from cooling, the basic ongoing task was khổng lồ prevent release of radioactive materials, particularly in contaminated water leaked from the three units. This task became newsworthy in August 2013.There have been no deaths or cases of radiation sickness from the nuclear accident, but over 100,000 people were evacuated from their homes as a preventative measure. Government nervousness has delayed the return of many.Official figures show that there have been 2313 disaster-related deaths among evacuees from Fukushima prefecture. Disaster-related deaths are in addition lớn the about 19,500 that were killed by the earthquake or tsunami.

The Great East japan Earthquake of magnitude 9.0 at 2.46 pm on Friday 11 March 2011 did considerable damage in the region, & the large tsunami it created caused very much more. The earthquake was centred 130 km offshore the thành phố of Sendai in Miyagi prefecture on the eastern coast of Honshu Island (the main part of Japan), và was a rare & complex double quake giving a severe duration of about 3 minutes. An area of the seafloor extending 650 km north-south moved typically 10-20 metres horizontally. Japan moved a few metres east & the local coastline subsided half a metre. The tsunami inundated about 560 km2 & resulted in a human death toll of about 19,500 & much damage to lớn coastal ports and towns, with over a million buildings destroyed or partly collapsed.

Eleven reactors at four nuclear power plants in the region were operating at the time & all shut down automatically when the earthquake hit. Subsequent inspection showed no significant damage khổng lồ any from the earthquake. The operating units which shut down were Tokyo Electric power Company's (Tepco's) Fukushima Daiichi 1, 2, 3, & Fukushima Daini 1, 2, 3, 4, Tohoku's Onagawa 1, 2, 3, và Japco's Tokai, total 9377 MWe net. Fukushima Daiichi units 4, 5&6 were not operating at the time, but were affected. The main problem initially centred on Fukushima Daiichi 1-3. Unit 4 became a problem on day five.

The reactors proved robust seismically, but vulnerable lớn the tsunami. Power, from grid or backup generators, was available khổng lồ run the residual heat removal (RHR) system cooling pumps at eight of the eleven units, and despite some problems they achieved 'cold shutdown' within about four days. The other three, at Fukushima Daiichi, lost power nguồn at 3.42 pm, almost an hour after the earthquake, when the entire site was flooded by the 15-metre tsunami. This disabled 12 of 13 backup generators onsite & also the heat exchangers for dumping reactor waste heat & decay heat lớn the sea. The three units lost the ability to lớn maintain proper reactor cooling and water circulation functions. Electrical switchgear was also disabled. Thereafter, many weeks of focused work centred on restoring heat removal from the reactors & coping with overheated spent fuel ponds. This was undertaken by hundreds of Tepco employees as well as some contractors, supported by firefighting & military personnel. Some of the Tepco staff had lost homes, and even families, in the tsunami, & were initially living in temporary accommodation under great difficulty and privation, with some personal risk. A hardened onsite emergency response centre was unable khổng lồ be used in grappling with the situation, due to lớn radioactive contamination.

Three Tepco employees at the Daiichi và Daini plants were killed directly by the earthquake & tsunami, but there have been no fatalities from the nuclear accident.

Among hundreds of aftershocks, an earthquake with magnitude 7.1, closer to lớn Fukushima than the 11 March one, was experienced on 7 April, but without further damage to lớn the plant. On 11 April a magnitude 7.1 earthquake and on 12 April a magnitude 6.3 earthquake, both with the epicentre at Fukushima-Hamadori, caused no further problems.

The two Fukushima plants & their siting

The Daiichi (first) và Daini (second) Fukushima plants are sited about 11 km apart on the coast, Daini to the south.

The recorded seismic data for both plants – some 180 km from the epicentre – shows that 550 Gal (0.56 g) was the maximum ground acceleration for Daiichi, & 254 Gal was maximum for Daini. Daiichi units 2, 3 và 5 exceeded their maximum response acceleration kiến thiết basis in an east-west direction by about 20%. The recording was over 130-150 seconds. (All nuclear plants in nhật bản are built on rock – ground acceleration was around 2000 Gal a few kilometres north, on sediments).

The original kiến thiết basis tsunami height was 3.1 m for Daiichi based on assessment of the 1960 Chile tsunami & so the plant had been built about 10 metres above sea level with the seawater pumps 4 m above sea level. The Daini plant was built 13 metres above sea level. In 2002 the thiết kế basis was revised khổng lồ 5.7 metres above, & the seawater pumps were sealed. In the event, tsunami heights coming ashore were about 15 metres, & the Daiichi turbine halls were under some 5 metres of seawater until levels subsided. Daini was less affected. The maximum amplitude of this tsunami was 23 metres at point of origin, about 180 km from Fukushima.

In the last century there have been eight tsunamis in the region with maximum amplitudes at origin above 10 metres (some much more), these having arisen from earthquakes of magnitude 7.7 lớn 8.4, on average one every 12 years. Those in 1983 and in 1993 were the most recent affecting Japan, with maximum heights at origin of 14.5 metres và 31 metres respectively, both induced by magnitude 7.7 earthquakes. The June 1896 earthquake of estimated magnitude 8.3 produced a tsunami with run-up height of 38 metres in Tohoku region, killing more than 27,000 people.

The tsunami countermeasures taken when Fukushima Daiichi was designed and sited in the 1960s were considered acceptable in relation to lớn the scientific knowledge then, with low recorded run-up heights for that particular coastline. But some 18 years before the 2011 disaster, new scientific knowledge had emerged about the likelihood of a large earthquake và resulting major tsunami of some 15.7 metres at the Daiichi site. However, this had not yet led khổng lồ any major action by either the plant operator, Tepco, or government regulators, notably the Nuclear & Industrial Safety Agency (NISA). Discussion was ongoing, but action minimal. The tsunami countermeasures could also have been reviewed in accordance with International Atomic Energy Agency (IAEA) guidelines which required taking into tài khoản high tsunami levels, but NISA continued khổng lồ allow the Fukushima plant to lớn operate without sufficient countermeasures such as moving the backup generators up the hill, sealing the lower part of the buildings, & having some back-up for seawater pumps, despite clear warnings.

A report from the Japanese government's Earthquake Research Committee on earthquakes & tsunamis off the Pacific coastline of northeastern nhật bản in February 2011 was due for release in April, and might finally have brought about changes. The document includes analysis of a magnitude 8.3 earthquake that is known khổng lồ have struck the region more than 1140 years ago, triggering enormous tsunamis that flooded vast areas of Miyagi & Fukushima prefectures. The report concludes that the region should be alerted of the risk of a similar disaster striking again. The 11 March earthquake measured magnitude 9.0 and involved substantial shifting of multiple sections of seabed over a source area of 200 x 400 km. Tsunami waves devastated wide areas of Miyagi, Iwate & Fukushima prefectures.

(See also background on Earthquakes and Seismic Protection for Nuclear nguồn Plants in Japan)

Events at Fukushima Daiichi 1-3 và 4

It appears that no serious damage was done khổng lồ the reactors by the earthquake, và the operating units 1-3 were automatically shut down in response lớn it, as designed. At the same time all six external nguồn supply sources were lost due khổng lồ earthquake damage, so the emergency diesel generators located in the basements of the turbine buildings started up. Initially cooling would have been maintained through the main steam circuit bypassing the turbine và going through the condensers.

Then 41 minutes later, at 3:42 pm, the first tsunami wave hit, followed by a second 8 minutes later. These submerged & damaged the seawater pumps for both the main condenser circuits và the auxiliary cooling circuits, notably the residual heat removal (RHR) cooling system. They also drowned the diesel generators & inundated the electrical switchgear & batteries, all located in the basements of the turbine buildings (the one surviving air-cooled generator was serving units 5&6). So there was a station blackout, và the reactors were isolated from their ultimate heat sink. The tsunamis also damaged và obstructed roads, making outside access difficult.

All this put reactors 1-3 in a dire situation and led the authorities to order, và subsequently extend, an evacuation while engineers worked to lớn restore power và cooling. The 125-volt DC back-up batteries for units 1&2 were flooded và failed, leaving them without instrumentation, control or lighting. Unit 3 had battery power nguồn for about 30 hours.

At 7:03 pm Friday 11 March a nuclear emergency was declared, and at 8:50pm the Fukushima prefecture issued an evacuation order for people within 2 km of the plant. At 9:23 pm the prime minister extended this khổng lồ 3 km, & at 5:44 am on 12 March he extended it to 10 km. He visited the plant soon after. Later on Saturday 12 March he extended the evacuation zone to đôi mươi km.

Inside the Fukushima Daiichi reactors

The Fukushima Daiichi reactors were GE boiling water reactors (BWRs) of an early (1960s) kiến thiết supplied by GE, Toshiba & Hitachi, with what is known as a Mark I containment. Reactors 1-3 came into commercial operation 1971-75. Reactor capacity was 460 MWe for unit 1, 784 MWe for units 2-5, & 1100 MWe for unit 6.

Xem thêm: Câu 14: để giảm thiểu ảnh hưởng tiêu cực của đô thị hóa nước ta cần

When the nguồn failed at 3:42 pm, about one hour after shutdown of the fission reactions, the reactor cores would still have been producing about 1.5% of their nominal thermal power, from fission hàng hóa decay – about 22 MW in unit 1 & 33 MW in units 2&3. Without heat removal by circulation to an outside heat exchanger, this produced a lot of steam in the reactor pressure vessels (RPVs) housing the cores, & this was released into the dry primary containment (PCV) through safety valves. Later this was accompanied by hydrogen, produced by the interaction of the fuel's very hot zirconium cladding with steam after the water cấp độ dropped.

As pressure started lớn rise here, the steam was directed into the suppression chamber/wetwell under the reactor, within the containment, but the internal temperature và pressure nevertheless rose quite rapidly. Water injection commenced, using the various systems provide for this and finally the emergency bộ vi xử lý core cooling system (ECCS). These systems progressively failed over three days, so from early Saturday water injection khổng lồ the RPV was with fire pumps, but this required the internal pressures lớn be relieved initially by venting into the suppression chamber/wetwell.Seawater injection into unit 1 began at 7:00 pm on Saturday 12, into unit 3 on Sunday 13 & unit 2 on Monday 14. Tepco management ignored an instruction from the prime minister khổng lồ cease the seawater injection into unit 1, and this instruction was withdrawn shortly afterwards.

Inside unit 1, it is understood that the water màn chơi dropped to the đứng top of the fuel about three hours after the scram (about 6:00 pm) & the bottom of the fuel 1.5 hours later (7:30 pm). The temperature of the exposed fuel rose to lớn some 2800°C so that the central part started lớn melt after a few hours & by 16 hours after the scram (7:00 am Saturday) most of it had fallen into the water at the bottom of the RPV. After that, RPV temperatures decreased steadily.

As pressure rose, attempts were made to vent the containment, & when external power & compressed air sources were harnessed this was successful, by about 2:30 pm Saturday, though some manual venting was apparently achieved at about 10:17 am. The venting was designed to be through an external stack, but in the absence of power nguồn much of it apparently backflowed to lớn the service floor at the top of the reactor building, representing a serious failure of this system (though another possibility is leakage from the drywell). The vented steam, noble gases và aerosols were accompanied by hydrogen. At 3:36 pm on Saturday 12, there was a hydrogen explosion on the service floor of the building above unit 1 reactor containment, blowing off the roof và cladding on the đứng đầu part of the building, after the hydrogen mixed with air và ignited. (Oxidation of the zirconium cladding at high temperatures in the presence of steam produces hydrogen exothermically, with this exacerbating the fuel decay heat problem.)

In unit 1 most of the core – as corium, composed of melted fuel & control rods – was assumed to lớn be in the bottom of the RPV, but later it appeared that it had mostly gone through the bottom of the RPV và eroded about 65 centimet into the drywell concrete below (which is 2.6 m thick). This reduced the intensity of the heat & enabled the mass to lớn solidify.

Much of the fuel in units 2&3 also apparently melted lớn some degree, but to lớn a lesser extent than in unit 1, & a day or two later. In mid-May 2011 the unit 1 bộ vi xử lý core would still have been producing 1.8 MW of heat, & units 2&3 about 3.0 MW each.

In mid-2013 the Nuclear Regulation Authority (NRA) confirmed that the earthquake itself had caused no damage lớn unit 1.

In unit 2, water injection using the steam-driven back-up water injection system failed on Monday 14, & it was about six hours before a fire pump started injecting seawater into the RPV. Before the fire pump could be used RPV pressure had khổng lồ be relieved via the wetwell, which required power and nitrogen, hence the delay. Meanwhile the reactor water cấp độ dropped rapidly after backup cooling was lost, so that core damage started about 8 pm, & it is now understood that much of the fuel then melted và probably fell into the water at the bottom of the RPV about 100 hours after the scram. Pressure was vented on Sunday 13 & again on Tuesday 15, and meanwhile the blowout panel near the top of the building was opened to lớn avoid a repetition of the hydrogen explosion at unit 1. Early on Tuesday 15, the pressure suppression chamber under the actual reactor seemed to rupture, possibly due to lớn a hydrogen explosion there, & the drywell containment pressure inside dropped. However, subsequent inspection of the suppression chamber did not tư vấn the rupture interpretation. Later analysis suggested that a leak of the primary containment developed on Tuesday 15.Most of the radioactive releases from the site appeared to lớn come from unit 2.

In unit 3, the main backup water injection system failed at about 11:00 am on Saturday 12, và early on Sunday 13 water injection using the high pressure system failed also and water levels dropped dramatically. RPV pressure was reduced by venting steam into the wetwell, allowing injection of seawater using a fire pump from just before noon. Early on Sunday venting the suppression chamber & containment was successfully undertaken. It is now understood that bộ vi xử lý core damage started about 5:30 am and much or all of the fuel melted on the morning of Sunday 13 and fell into the bottom of the RPV, with some probably going through the bottom of the reactor pressure vessel & onto the concrete below.

Early on Monday 14 PCV venting was repeated, và this evidently backflowed lớn the service floor of the building, so that at 11:00 am a very large hydrogen explosion here above unit 3 reactor containment blew off much of the roof & walls and demolished the đứng top part of the building. This explosion created a lot of debris, & some of that on the ground near unit 3 was very radioactive.

In defuelled unit 4, at about 6:00 am on Tuesday 15 March, there was an explosion which destroyed the đứng top of the building và damaged unit 3's superstructure further. This was apparently from hydrogen arising in unit 3 và reaching unit 4 by backflow in shared ducts when vented from unit 3.

Units 1-3: Water had been injected into each of the three reactor units more or less continuously, & in the absence of normal heat removal via external heat exchanger this water was boiling off for some months. In the government report to lớn the IAEA in June it was estimated that lớn the kết thúc of May about 40% of the injected water boiled off, & 60% leaked out the bottom. In June 2011 this was adding to lớn the contaminated water onsite by about 500 m3 per day. In January 2013 4.5 lớn 5.5 m3/h was being added to lớn each RPV via bộ vi xử lý core spray & feedwater systems, hence 370 m3 per day, & temperatures at the bottom of RPVs were 19°C in unit 1 & 32°C in units 2&3, at little above atmospheric pressure.

There was a peak of radioactive release on Tuesday 15, apparently mostly from unit 2, but the precise source remains uncertain. Due khổng lồ volatile và easily-airborne fission products being carried with the hydrogen and steam, the venting & hydrogen explosions discharged a lot of radioactive material into the atmosphere, notably iodine & caesium. NISA said in June that it estimated that 800-1000kg of hydrogen had been produced in each of the units.

Nitrogen was being injected into the PCVs of all three reactors khổng lồ remove concerns about further hydrogen explosions, và in December this was started also for the pressure vessels. Gas control systems which extract & clean the gas from the PCV lớn avoid leakage of caesium were commissioned for all three units.

Throughout 2011 injection into the RPVs of water circulated through the new water treatment plant achieved relatively effective cooling, & temperatures at the bottom of the RPVs were stable in the range 60-76°C at the over of October, và 27-54°C in mid-January 2012. RPV pressures ranged from atmospheric to slightly above (102-109k
Pa) in January, due lớn water and nitrogen injection. However, since they were leaking, the normal definition of 'cold shutdown' did not apply, & Tepco waited to lớn bring radioactive releases under control before declaring 'cold shutdown condition' in mid-December, with NISA's approval. This, with the prime minister's announcement of it, formally brought to lớn a close the 'accident' phase of events.

The AC electricity supply from external source was connected khổng lồ all units by 22 March. Power was restored to instrumentation in all units except unit 3 by 25 March. However, radiation levels inside the plant were so high that normal access was impossible until June.

Event sequence following earthquake (timing from it: 14:46, 11 March)

Unit 1Unit 2Unit 3

Loss of AC power	+ 51 min	+ 54 min	+ 52 min
Loss of cooling	+ 1 hour	+ 70 hours	+ 36 hours
Water level down to đứng top of fuel*	+ 3 hours	+ 74 hours	+ 42 hours
Core damage starts*	+ 4 hours	+ 77 hours	+ 44 hours
Reactor pressure vessel damage*	+11 hours	uncertain	uncertain
Fire pumps with fresh water	+ 15 hours		+ 43 hours
Hydrogen explosion (not confirmed for unit 2)	+ 25 hoursservice floor	+ 87 hourssuppression chamber	+ 68 hoursservice floor
Fire pumps with seawater	+ 28 hours	+ 77 hours	+ 46 hours
Offsite electrical supply	+ 11-15 days
Fresh water cooling	+ 14-15 days

* according khổng lồ 2012 MAAP (Modular Accident Analysis Program) analysis

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.

Results of muon measurements in unit 2 in 2016 indicate that most of the fuel debris in unit 2 is in the bottom of the reactor vessel.

Tepco has written off the four reactors damaged by the accident, and is decommissioning them.

Summary: Major fuel melting occurred early on in all three units, though the fuel remained essentially contained except for some volatile fission products vented early on, or released from unit 2 in mid-March, và some soluble ones which were leaking with the water, especially from unit 2, where the containment is evidently breached. Cooling is provided from external sources, using treated recycled water, with a stable heat removal path from the actual reactors to lớn external heat sinks. Access has been gained to all three reactor buildings, but dose rates remain high inside. Tepco declared 'cold shutdown condition' in mid-December 2011 when radioactive releases had reduced to minimal levels.

(See also background on nuclear reactors at Fukushima Daiichi.)

Fuel ponds: developing problems

Used fuel needs lớn be cooled & shielded. This is initially by water, in ponds. After about three years underwater, used fuel can be transferred lớn dry storage, with air ventilation simply by convection. Used fuel generates heat, so the water in ponds is circulated by electric pumps through external heat exchangers, so that the heat is dumped & a low temperature maintained. There are fuel ponds near the đứng top of all six reactor buildings at the Daiichi plant, adjacent to lớn the top of each reactor so that the fuel can be unloaded underwater when the đứng top is off the reactor pressure vessel và it is flooded. The ponds hold some fresh fuel và some used fuel, the latter pending its transfer khổng lồ the onsite central used/spent fuel storage. (There is some dry storage onsite to lớn extend the plant's capacity.)

At the time of the accident, in addition to a large number of used fuel assemblies, unit 4's pond also held a full bộ vi xử lý core load of 548 fuel assemblies while the reactor was undergoing maintenance, these having been removed at the end of November, và were lớn be replaced in the core.

A separate set of problems arose as the fuel ponds, holding fresh and used fuel in the upper part of the reactor structures, were found lớn be depleted in water. The primary cause of the low water levels was loss of cooling circulation lớn external heat exchangers, leading to elevated temperatures và probably boiling, especially in the heavily-loaded unit 4 fuel pond. Here the fuel would have been uncovered in about 7 days due to water boiling off. However, the fact that unit 4 was unloaded meant that there was a large inventory of water at the đứng đầu of the structure, and enough of this replenished the fuel pond to prevent the fuel becoming uncovered – the minimum level reached was about 1.2 m above the fuel on about 22 April.

After the hydrogen explosion in unit 4 early on Tuesday 15 March, Tepco was told to implement injection of water to unit 4 pond which had a particularly high heat load (3 MW) from 1331 used fuel assemblies in it, so it was the main focus of concern. It needed the addition of about 100 m3/day to lớn replenish it after circulation ceased.

From Tuesday 15 March attention was given lớn replenishing the water in the ponds of units 1, 2&3 as well. 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. There was some use of built-in plumbing for unit 2. Analysis of radionuclides in water from the used fuel ponds suggested that some of the fuel assemblies might have been damaged, but the majority were intact.

There was concern about the structural strength of unit 4 building, so support for the pond was reinforced by the kết thúc of July.

New cooling circuits with heat exchangers adjacent to lớn the reactor buildings for all four ponds were commissioned after a few months, và each reduced the pool temperature from 70 °C to lớn normal in a few days. Each has a primary circuit within the reactor & waste treatment buildings & a secondary circuit dumping heat through a small dry cooling tower outside the building.

The next task was khổng lồ remove the salt from those ponds which had seawater added, to lớn reduce the potential for corrosion.

In July 2012 two of the 204 fresh fuel assemblies were removed from the unit 4 pool and transferred khổng lồ the central spent fuel pool for detailed inspection to kiểm tra damage, particularly corrosion. They were found to have no deformation or corrosion. Unloading the 1331 spent fuel assemblies in pond 4 và transferring them lớn the central spent fuel pool commenced in mid-November 2013 & was completed 13 months later. These comprised 783 spent fuel plus the full fuel load of 548.

The next focus of attention was the unit 3 pool. In năm ngoái the damaged fuel handling equipment & other wreckage was removed from the destroyed upper cấp độ of the reactor building. Toshiba built a 74-tonne fuel handling machine for transferring the 566 fuel assemblies into casks và to remove debris in the pool, and a crane for lifting the fuel transfer casks. Installation of a cover over the fuel handling machine was completed in February 2018. Removal & transferral of the fuel khổng lồ the central spent fuel pool began in mid-April 2019 & was completed at the kết thúc of February 2021.

The onsite central spent fuel pool in 2011 held about 60% of the Daiichi used fuel, and is immediately west (inland) of unit 4. It lost circulation with the power outage, & temperature increased khổng lồ 73°C by the time mains power và cooling were restored after two weeks.In late 2013 this pond, with capacity for 6840*, held 6375 fuel assemblies, the same as at the time of the accident. In June 2018, Tepco announced it would transfer some of the fuel assemblies stored in the central spent fuel pool lớn an onsite temporary dry storage facility to lớn clear sufficient space for the fuel assemblies from unit 3's pool. The dry storage facility has a capacity of at least 2930 assemblies in 65 casks – each dry cask holds 50 fuel assemblies. Eventually these will be shipped khổng lồ JNFL’s Rokkasho reprocessing plant or lớn Recyclable Fuel Storage Company’s Mutsu facility.

* effectively 6750, due to one rack of 90 having some damaged fuel.

Summary: The spent fuel storage pools survived the earthquake, tsunami & hydrogen explosions without significant damage lớn the fuel, significant radiological release, or threat to lớn public safety. The new cooling circuits with external heat exchangers for the four ponds are working well và temperatures are normal. Analysis of water has confirmed that most fuel rods are intact. All fuel assemblies have been removed from the unit 3&4 pools.

(See also background on Fukushima Fuel Pondsand Decommissioning section below.)

Radioactive releases to lớn air

Regarding releases to lớn air & also water leakage from Fukushima Daiichi, the main radionuclide from among the many kinds of fission products in the fuel was volatile iodine-131, which has a half-life of 8 days. The other main radionuclide is caesium-137, which has a 30-year half-life, is easily carried in a plume, & when it lands it may contaminate land for some time. It is a strong gamma-emitter in its decay. Cs-134 is also produced & dispersed; it has a two-year half-life. Caesium is soluble and can be taken into the body, but does not concentrate in any particular organs, & has a biological half-life of about 70 days. In assessing the significance of atmospheric releases, the Cs-137 figure is multiplied by 40 & added to lớn the I-131 number khổng lồ give an 'iodine-131 equivalent' figure.

As cooling failed on the first day, evacuations were progressively ordered, due khổng lồ uncertainty about what was happening inside the reactors và the possible effects. By the evening of Saturday 12 March the evacuation zone had been extended to đôi mươi km from the plant. From đôi mươi to 30km from the plant, the criterion of đôi mươi m
Sv/yr dose rate was applied lớn determine evacuation, and is now the criterion for return being allowed. 20 m
Sv/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 m
Sv/yr from April 2012 residency is restricted, with remediation kích hoạt taken. See later section on Public health and return of evacuees.

A significant problem in tracking radioactive release was that 23 out of the 24 radiation monitoring stations on the plant site were disabled by the tsunami.

There is some uncertainty about the amount and exact sources of radioactive releases khổng lồ air (see also background on Radiation Exposure).

Japan’s regulator, the Nuclear & Industrial Safety Agency (NISA), estimated in June 2011 that 770 PBq (iodine-131 equivalent) of radioactivity had been released, but the Nuclear Safety Commission (NSC, a policy body) in August lowered this estimate lớn 570 PBq. The 770 PBq figure is about 15% of the Chernobyl release of 5200 PBq iodine-131 equivalent. Most of the release was by the kết thúc of March 2011.

Tepco sprayed a dust-suppressing polymer resin around the plant to lớn ensure that fallout from mid-March was not mobilized by wind or rain. In addition it removed a lot of rubble with remote control front-end loaders, & this further reduced ambient radiation levels, halving them near unit 1. The highest radiation levels onsite came from debris left on the ground after the explosions at units 3&4.

Reactor covers

In mid-May 2011 work started towards constructing a cover over unit 1 to reduce airborne radioactive releases from the site, khổng lồ keep out the rain, & to enable measurement of radioactive releases within the structure through its ventilation system. The frame was assembled over the reactor, enclosing an area 42x 47m, và 54m high. The sections of the steel frame fitted together remotely without the use of screws and bolts. All the wall panels had a flameproof coating, và the structure had a filtered ventilation system capable of handling 40,000 cubic metres of air per hour through six lines, including two backup lines. The cover structure was fitted with internal monitoring cameras, radiation và hydrogen detectors, thermometers and a pipe for water injection. The cover was completed with ventilation systems working by the end of October 2011. It was expected khổng lồ be needed for two years. In May 2013 Tepco announced its more permanent replacement, to lớn be built over four years. It started demolishing the 2011 cover in năm trước and finished in 2016. In December 2019 it decided to install the replacement cover before removing debris from the đứng đầu floor of the building. A crane and other equipment for fuel removal will be installed under the cover, similar to lớn that over unit 4.

More substantial covers were designed to lớn fit around units 3&4 reactor buildings after the vị trí cao nhất floors were cleared up in 2012.

A cantilevered structure was built over unit 4 from April 2012 khổng lồ July 2013 khổng lồ enable recovery of the contents of the spent fuel pond.This is a 69 x 31 m cover (53 m high) and it was fully equipped by the over of 2013 lớn enable unloading of used fuel from the storage pond into casks, each holding 22 fuel assemblies, và removal of the casks.This operation was accomplished under water, using the new fuel handling machine (replacing the one destroyed by the hydrogen explosion) so that the used fuel could be transferred to the central storage onsite. Transfer was completed in December 2014. A clip of the process is available on Tepco's website.

A different kiến thiết of cover was built overunit 3, & foundation work began in 2012.Large rubble removal took place from 2013 to lớn 2015, including the damaged fuel handling machine. An arched cover was prefabricated, 57 m long và 19 m wide, and supported by the turbine building on one side and the ground on the other. Acrane removed the 566 fuel assemblies from the pool and some remaining rubble. Spent fuel removal from unit 3 pool began in April 2019 and was completed in February 2021. Spent fuel removal from units 1&2 pools was scheduled in 2018, but is now scheduled to begin in 2023.

Maps from the Ministry of Education, Culture, Sports, Science and Tehcnology (MEXT) aerial surveys carried out approximately one year apart show the reduction in contamination from late 2011 lớn late 2012. Areas with colour changes in 2012 showed approximately half the contamination as surveyed in 2011, the difference coming from decay of caesium-134 (two-year half-life) và natural processes lượt thích wind và rain. In blue areas, ambient radiation is very similar lớn global background levels at

Sequence of evacuation orders based on the report by The National Diet of japan Fukushima Nuclear Accident Independent Investigation Commission:

11 March14:46 JST The earthquake occurred.15:42 TEPCO made the first emergency report to the government.19:03 The government announced nuclear emergency.20:50 The Fukushima Prefecture Office ordered 2km radius evacuation.21:23 The government ordered 3km evacuation & to keep staying inside buildings in the area of 3-10km radius.

12 March05:44 The government ordered 10km radius evacuation.18:25 The government ordered 20km evacuation.

15 March11:01 The government ordered khổng lồ keep staying inside buildings in the area of 20-30km from the plant.

25 March The government requested voluntary evacuation in the area of 20-30km.

21 April The government mix the 20km radius no-go area.

Radiation exposure on the plant site

By the over of 2011, Tepco had checked the radiation exposure of 19,594 people who had worked on the site since 11 March. For many of these both external dose và internal doses (measured with whole-body counters) were considered. It reported that 167 workers had received doses over 100 m
Sv. Of these 135 had received 100 lớn 150 m
Sv, twenty-three 150-200 m
Sv, three more 200-250 m
Sv, và six had received over 250 m
Sv (309 khổng lồ 678 m
Sv) apparently due khổng lồ inhaling iodine-131 fumes early on. The latter included the units 3&4 control room operators in the first two days who had not been wearing breathing apparatus. There were up to 200 workers onsite each day. Recovery workers wear personal monitors, with breathing apparatus and protective clothing which protect against alpha and beta radiation. The level of 250 m
Sv was the allowable maximum short-term dose for Fukushima Daiichi accident clean-up workers through to December 2011, 500 m
Sv is the international allowable short-term dose "for emergency workers taking life-saving actions". In January 2012 the allowable maximum reverted to 50 m
Sv/yr.

No radiation casualties (acute radiation syndrome) occurred, & few other injuries, though higher than normal doses, were being accumulated by several hundred workers onsite. High radiation levels in the three reactor buildings hindered access there.

Monitoring of seawater, soil và atmosphere is at 25 locations on the plant site, 12 locations on the boundary, and others further afield. Government and IAEA monitoring of air and seawater is ongoing. Some high but not health-threatening levels of iodine-131 were found in March, but with an eight-day half-life, most I-131 had gone by the kết thúc of April 2011.

A radiation survey bản đồ of the site made in March 2013 revealed substantial progress: the highest dose rate anywhere on the site was 0.15 m
Sv/h near units 3 & 4. (Soon after the accident a similar survey put the highest dose rate at 300 m
Sv/h near rubble lying alongside unit 3.) The majority of the power plant area was at less than 0.01 m
Sv/h. These reduced levels are reflected in worker doses: during January 2013, the 5702 workers at the site received an average of 0.86 m
Sv, with 75% of workers recorded as receiving less than 1 m
Sv. In total, only about 2% of workers received over 5 m
Sv and the highest dose in January was 12.65 m
Sv for one worker.

Media reports have referred to 'nuclear gypsies' – casual workers employed by subcontractors on a short-term basis, & allegedly prone to lớn receiving higher and unsupervised radiation doses. This transient workforce has been part of the nuclear scene for at least four decades, & at Fukushima their doses are very rigorously monitored. If they reach certain levels, e.g. 30 m
Sv but varying according to lớn circumstance, they are reassigned lớn lower-exposure areas.

Tepco figures submitted lớn the NRA for the period to kết thúc January 2014 showed 173 workers had received more than 100 m
Sv (six more than two years earlier) and 1578 had received 50 to lớn 100 m
Sv.This was among a total of 32,024, 64% more than had worked there two years earlier. Since April 2013 none of the 13,154 who had worked onsite had received more than 50 m
Sv, & 96% of these had less than a trăng tròn m
Sv dose. Early in 2014 there were about 4000 onsite each weekday.

Summary: Six workers received radiation doses apparently over the 250 m
Sv cấp độ set by NISA, but at levels below those which would cause radiation sickness.

Radiation exposure and fallout beyond the plant site

On 4 April 2011, radiation levels of 0.06 m
Sv/day were recorded in Fukushima city, 65 km northwest of the plant, about 60 times higher than normal but posing no health risk according khổng lồ authorities. Monitoring beyond the đôi mươi km evacuation radius lớn 13 April showed one location – around Iitate – with up to 0.266 m
Sv/day dose rate, but elsewhere no more than one-tenth of this. At the over of July the highest level measured within 30km radius was 0.84 m
Sv/day in Namie town, 24 km away. The safety limit mix by the central government in mid-April for public recreation areas was 3.8 microsieverts per hour (0.09 m
Sv/day).

In June 2013, analysis from Japan's Nuclear Regulation Authority (NRA) showed that the most contaminated areas in the Fukushima evacuation zone had reduced in kích cỡ by three-quarters over the previous two years. The area subject to lớn high dose rates (over 166 m
Sv/yr) diminished from 27% of the 1117 km2 zone to 6% over 15 months lớn March 2013, và in the ‘no residence’ portion (originally 83-166 m
Sv/yr) no areas remained at this level và 70% was below 33 m
Sv/yr. The least-contaminated area is now entirely below 33 m
Sv/yr.

In August 2011 The Act on Special Measures Concerning the Handling of Radioactive Pollution was enacted & it took full effect from January 2012 as the main legal instrument to giảm giá 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 trăng tròn km radius from the Fukushima Daiichi plant, and 'deliberate evacuation areas' where the annual cumulative dose for individuals was anticipated lớn exceed 20 m
Sv. The national government promotes decontamination in these areas. These areas are subdivided into three: dose 1-20 m
Sv/yr (green); dose 20-50 m
Sv/yr (yellow); và dose over 50 m
Sv/yr & over 20 m
Sv/yr averaged over 5 years (red).Intensive Contamination Survey Areas including the so-called Decontamination Implementation Areas, where an additional annual cumulative dose between 1 m
Sv and 20 m
Sv was estimated for individuals. Municipalities implement decontamination activities in these areas.

Following a detailed study by 80 international experts, the UN Scientific Committee on the Effects of Atomic Radiation's (UNSCEAR's) May 2013 Report to the General Assembly concluded: "No radiation-related deaths or acute diseases have been observed among the workers và general public exposed lớn radiation from the accident. The doses to lớn the general public, both those incurred during the first year & 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 160 additional workers received effective doses currently estimated to be over 100 m
Sv, 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 lớn 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. UNSCEAR’s follow-up trắng paper in October 2015 said that none of the new information appraised after the 2013 report “materially affected the main findings or challenged the major assumptions of the 2013 Fukushima report."

By contrast, the public was exposed khổng lồ 10-50 times less radiation. Most Japanese people were exposed to lớn additional radiation amounting lớn less than the typical natural background level of 2.1 m
Sv per year.

In 2018 UNSCEAR decided khổng lồ update the 2013 report to reflect the latest findings. In March 2021, UNSCEAR published its 2020 Report, which broadly confirms the major findings và conclusions of the 2013 report. The 2020 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. The Committee’s revised estimates of dose are such that future radiation-associated health effects are unlikely to lớn be discernible."

People living in Fukushima prefecture are expected to be exposed to lớn around 10 m
Sv over their entire lifetimes, while for those living further away the dose would be 0.2 m
Sv per year. 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 lớn the most exposed people possible: a postulated girl under one year of age living in Iitate or Namie that did not evacuate & 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 lớn the WHO's analysis.

Despite the conclusions of reports from UNSCEAR & the WHO, the Japanese government in 2018 acknowledged a connection between the death of a former plant worker & radiation exposure. The man had been diagnosed with lung cancer in February 2016.

Eleven municipalities in the former restricted zone or planned evacuation area, within đôi mươi km of the plant or where annual cumulative radiation dose is greater than trăng tròn m
Sv, are designated 'special decontamination areas', where decontamination work is being implemented by the government. A further 100 municipalities in eight prefectures, where dose rates are equivalent to over 1 m
Sv per year are classed as 'intensive decontamination survey areas', where decontamination is being implemented by each municipality with funding và technical tư vấn from the national government. Decontamination of all 11 special decontamination areas has been completed.

In October 2013 a 16-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. If annual radiation dose was below trăng tròn m
Sv, such as generally in intensive decontamination survey areas, this cấp độ was “acceptable and in line with the international standards and with the recommendations from the relevant international organizations, e.g. ICRP, IAEA, UNSCEAR and WHO.” The clear implication was that people in such areas should be allowed to lớn return home. Furthermore the government should increase efforts to communicate this to lớn the public, và should explain that its long-term goal of achieving an additional individual dose of 1 m
Sv/yr is unrealistic và unnecessary in the short term. Also, there is potential khổng lồ produce more food safely in contaminated areas.

Radioactivity, primarily from caesium-137, in the evacuation zone and other areas beyond it has been reported in terms of k
Bq/kg (compared with k
Bq/m2around Chernobyl. A total of 3000 km2was contaminated above 180 k
Bq/m2, compared with 29,400 km2from Chernobyl). However the main measure has been presumed doses in m
Sv/yr. The government has adopted trăng tròn m
Sv/yr as its goal for the evacuation zone & more contaminated areas outside it, and supports municipal government work khổng lồ reduce levels below that. The total area under consideration for attention is 13,000 km2.In năm 2016 the Ministry of Environmentannounced that material with less than 8 k
Bq/kg caesium would no longer be specified as waste, và subject to restrictions on disposal. It allowed use of contaminated soil for embankments, where the activity was less then 8 k
Bq/kg, và unrestricted use if less than 100 Bq/kg. Most of the stored wastes have decayed to below the 8 k
Bq/kg level.

Summary: There have been no harmful effects from radiation on local people, nor any doses approaching harmful levels. However, some 160,000 people were evacuated from their homes và only from 2012 were allowed limited return.As of July 2020 over 41,000 remained displaced due lớn government concern about radiological effects from the accident.

Public health and return of evacuees

Permanent return remains a high priority, & the evacuation zone is being decontaminated where required and possible, so that evacuees can return. There are many cases of evacuation bít tất tay including transfer trauma among evacuees, và once the situation had stabilized at the plant these outweighed the radiological hazards of returning, with 2313 deaths reported (see below).

In December 2011 the government said that where annual radiation dose would be below 20 m
Sv/yr, the government would help residents return trang chủ as soon as possible và assist local municipalities with decontamination and repair of infrastructure. In areas where radiation levels are over trăng tròn m
Sv/yr evacuees will be asked lớn continue living elsewhere for “a few years” until the government completes decontamination và recovery work. The government said it would consider purchasing land và houses from residents of these areas if the evacuees wish to sell them.

In November 2013 the NRA decided khổng lồ 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. The same criteria would be used, as above, with đôi mươi m
Sv/yr being the threshold of concern lớn authorities.

In February năm trước the results of a study were published showing that 458 residents of two study areas 20 to 30 km from the plant và a third one 50 km northwest received radiation doses from the contaminated ground similar lớn the country’s natural background levels. Measurement was by personal dosimeters over August-September 2012.

By September 2020, 2313 disaster-related deaths among evacuees from Fukushima prefecture*, that were not due to lớn radiation-induced damage or to the earthquake or lớn the tsunami, had been identified by the Japanese authorities. About 90% of deaths were for persons above 66 years of age. Of these, about 30% occurred within the first three months of the evacuations, và about 80% within two years.

* An additional 1454 disaster-related deaths have been reported among evacuees from other tsunami- & earthquake-related prefectures. Disaster-related deaths are in addition khổng lồ the over 19,500 that died in the actual earthquake & tsunami.

The premature disaster-related deaths were mainly related lớn (i) physical & mental illness brought about by having to lớn reside in shelters và the trauma of being forced khổng lồ move from care settings và homes; và (ii) delays in obtaining needed medical support because of the enormous destruction caused by the earthquake & 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.

Evacuees over a period of six years received ¥100,000 (about $1000) per month in psychological suffering compensation. The money was tax-exempt và paid unconditionally. In October 2013, about 84,000 evacuees received the payments. Statistics indicate that an average family of four has received about ¥90 million ($900,000) in compensation from Tepco.As of January 2021 the Fukushima accident evacuees had received ¥9.7 trillion in personal và property compensation.

In April 2019, the first residents of Okuma, the closest town to lớn the plant, were allowed to lớn return home.In August 2022 the last remaining evacuation order – for Futaba, the town that hosts the Fukushima plant – was lifted.

According to a survey released by the prefectural government in April 2017, the majority of people who voluntarily evacuated their homes after the accident và who are now living outside of Fukushima prefecture bởi vì not intend lớn return. AMainichireport said that 78.2% of respondents lớn the survey preferred to lớn continue living in the area to lớn which they had moved, while only 18.3% intended lớn move back to lớn the prefecture. Of the voluntary evacuees still living in Fukushima prefecture, 23.6% planned khổng lồ stay where they were, while 66.6% hoped to return to lớn their origina