Timeline of the Fukushima I nuclear accidents

Jump to: navigation, search
During the 2011 Fukushima nuclear emergency in Japan, four nuclear reactors were damaged by explosions.

Fukushima Dai-ichi (dai-ichi means "number one"), is a disabled nuclear power plant. The Fukushima I nuclear accidents occurred after the 9.0 magnitude 2011 Tohoku earthquake and tsunami on 11 March. This offshore earthquake near the island of Honshu[1] produced a large tsunami in Japan, and a tsunami warning for over 20 countries. The earthquake triggered the shut down of the three active reactors at the Fukushima I Nuclear Power Plant (Fukushima Dai-Ichi). The subsequent tsunami stopped Fukushima I station's backup diesel generators, causing a station blackout. The subsequent lack of cooling led to explosions and partial meltdowns at the Fukushima I facility, with problems at all six reactor units and the central spent fuel pool.

[edit] Timeline

Times are given in Japan Standard Time (JST), unless noted, which is UTC plus nine hours.

[edit] March event tree

The nuclear accident event tree[2] developed quickly in the early weeks after the earthquake and tsunami caused a number of accident sequences to begin.

[edit] First week

[edit] 11 March

14:46: A 9.0 magnitude earthquake strikes off the coast of Honshu Island at a depth of about 24 kilometres (15 mi). The Fukushima I power plant's nuclear reactors 1, 2, and 3 are automatically shut down by the shake. Nuclear reactors 4, 5, and 6 were undergoing routine maintenance and were not operating, (reactor 4 was defueled in November 2010). The tremor has the additional effect of causing the power plant to be cut off from the Japanese electricity grid, however, backup diesel generators kick in to continue cooling. Tokyo Electric Power Company (TEPCO), the plant's operator, finds that units 1 and 2 are not operating correctly and notifies the proper officials.[3]

15:01 (approximate): A 14-metre (46 ft) tsunami unleashed by the earthquake overtops the seawall designed to protect the plant from a tsunami of 5.7 metres (19 ft), inundating the Fukushima facility and disabling the backup generators whose electricity was then required to operate controls and cool the reactors.[4]

According to a report in the New York Times, "[A]t the start of the crisis Friday, immediately after the shattering earthquake, Fukushima plant officials focused their attention on a damaged storage pool for spent nuclear fuel at the No. 2 reactor at Fukushima I, said a nuclear executive who requested anonymity.... The damage prompted the plant’s management to divert much of the attention and pumping capacity to that pool, the executive added. The shutdown of the other reactors then proceeded badly, and problems began to cascade."[5]

16:00: The Nuclear and Industrial Safety Agency of Japan (NISA) initiates an emergency headquarters in an attempt to gather information on the 55 nuclear reactors in Japan.[6] There is no report that radiation was detected outside plant borders.[7]

19:03: Prime Minister Naoto Kan declares a nuclear emergency status.[8] This is announced by Yukio Edano, Chief Cabinet officer in Japan. Japanese government officials try to comfort the people of Japan by telling them that the proper procedures are being undertaken. They also announce that no radioactive leaks have been detected.[6]

21:00: An evacuation order is issued by the government to persons within a 3 kilometres (1.9 mi) radius of the Fukushima I station. Those within a 10 kilometres (6.2 mi) radius are told that they can remain in their homes and carry on with regular activities until told otherwise.[6]

At Fukushima I, the ongoing lack of electricity is causing the cooling system to fail, and the pressure within the nuclear units build up. This pressure buildup is the result of residual decay heat causing the coolant, which is not being circulated, to evaporate.[9] There is no confirmation of radiation leaking from the reactor.[10] TEPCO announces that pressure inside reactor unit 1 of Fukushima I is more than twice normal levels.[6]

[edit] 12 March
Overview map showing evacuation and other zone progression and selected radiation levels.

02:44: Emergency battery power for the High Pressure Core Flooder System for Reactor 3 runs out.

04:15: Fuel rods in Reactor 3 are exposed.

05:30: Despite the high risk of the hydrogen igniting after combining with oxygen from water or in the atmosphere, in order to release some of the pressure inside the reactor at Fukushima I unit 1, the decision is taken to vent some of the steam (which contained a small amount of radioactive material) into the air in the metal container building surrounding the unit.

10:09: TEPCO confirms that a small amount of vapor has been released into the air to release pressure in reactor unit 1 at Fukushima I.[11]

10:58: Pressure still remains too high inside reactor unit 2 at Fukushima I. In order to alleviate some of this pressure, a consensus is once more reached to vent radioactive vapor into the air.[11]

15:30: Evacuation of residents within 3 km of Fukushima II and within 10 km of Fukushima I are underway.[12]

15:36: At reactor unit 1 at Fukushima I cameras document a massive hydrogen explosion on the outer structure of one of four buildings at the plant. It also documents the outer structure collapsing.

18:36 (approximately): TEPCO announces that four people who are employed at the power plant have been injured in the unit 1 explosion.

20:00: Uncertainty surrounds the actual cause of the blast at Fukushima I (later identified as a hydrogen explosion) and the damage caused.

Yukio Edano announces that the concrete building surrounding the steel reactor vessel at unit 1 in Fukushima I has collapsed as a result of the explosion; however no damage is believed to have been sustained by the reactor itself.

21:40: The evacuation zone around Fukushima I is extended to 20 km, while the evacuation zone around Fukushima II is extended to 10 km.[12]

To release pressure within reactor unit 1 at Fukushima I, steam is released out of the unit into the air. This steam contains water vapor, hydrogen, oxygen and some radioactive material, mostly tritium and nitrogen-16.

TEPCO engineers decided to directly inject sea water inside the pressure vessel of the reactors by means of the mobile trucks of the firemen, a brilliant ideas which avoided the situation to worsen. The pressure relief was also necessary to allow the firemen to inject seawater into the reactors vessels.

[edit] 13–17 March

[edit] Second week

[edit] 18–24 March

[edit] Third week

[edit] 25–31 March
  • 25 March: NISA announced a possible breach in the containment vessel of the unit 3 reactor, though radioactive water in the basement might alternatively have come the fuel storage pool.[60][61] Highly radioactive water was also found in the turbine buildings of units 1 and 2.[62] The US Navy sent a barge with 1,890 cubic metres (500,000 USgal) of fresh water, expected to arrive in two days.[63] Japan announced transportation would be provided in a voluntary evacuation zone of 30 kilometres (19 mi). Tap water was reported to be safe for infants in Tokyo and Chiba by Japanese authorities, but still exceeded limits in Hitachi and Tokaimura.[64] Iodine-131 in the ocean nearby measured 50 Bq/ml, a "relatively high" 1,250 times normal.[65]
    • White vapour, possibly steam, emanating from the buildings of reactors 2, 3, and 4.
    • The roof of the reactor 2 building has been badly damaged but is still intact.
    • The reactor 3 building is largely uncovered, its roof blown off in a hydrogen explosion over two weeks prior.
    • The walls of the reactor 4 building have also collapsed.

    [edit] April event tree

    The nuclear accident event tree continued to evolve in the second month after the earthquake and tsunami caused the accident sequence to begin.

    [edit] Fourth week

    [edit] Saturday, 2 April

    TEPCO observed for the first time that contaminated water from the unit 2 was flowing into the sea.[88] Workers discovered a crack about 20 cm (8 inches) wide in the maintenance pit, which lies between the reactor 2 and the sea and holds cables used to power seawater pumps.

    [edit] Sunday, 3 April

    The radioactive water leaked into the sea by unit 2 continued despite concrete pumped Saturday evening. Workers injected a mixture of a water-absorbing polymer, sawdust and shredded paper.[89] Radiation levels in the water were estimated at 1 Sv/h.

    TEPCO announced that the bodies of two workers killed by the tsunami were discovered on 30 March.[90]

    On Sunday, April 3, Japanese government officials said the Daiichi plant may continue to release dangerous radiation into the air for several months.[91]

    [edit] Monday, 4 April

    TEPCO began dumping water tainted with low levels of radioactivity into the Pacific Ocean on Monday night, 4 April, so that a central waste facility could be used to store more dangerously radioactive water, officials said. The company said it could release up to 11,500 tons of radioactive water into the sea. A spokeswoman for Japan’s Nuclear and Industrial Safety Agency said the less-contaminated water must be disposed of so that workers can secure a place to store more highly contaminated water on the site.[92]

    Engineers consider plans to inject inert nitrogen gas into the containment buildings of units 1, 2 and 3 to expel atmospheric oxygen and to dilute accumulated hydrogen, which combine explosively.[93]

    [edit] Tuesday, 5 April

    It was determined that the leak in the cable storage pit by unit 2 was likely due to a faulty joint where the pit meets a duct, leading to a gravel layer beneath, resulting in highly radioactive water pouring directly into the sea.[94][95]

    [edit] Wednesday, 6 April

    TEPCO announced that an injection of 6,000 litres (1,600 USgal) of polymer coagulant into the pit mitigated the leaking;[96] however, the IAEA and others credit additional factors.[97] Sodium silicate, also known as "water glass", and additives were injected into the ground in order to stop the leakage of radioactive water.[98] The residual heat carried by the water used for cooling the damaged reactors accelerated the setting of the injected mixture.

    Despite protests from the South Korean government, Russian scientists, and Japanese fishermen, Japan authorized the release of the 11,500 tonnes (12,700 tons) of less radioactive water into the ocean to make room to store more highly contaminated water.[95][99]

    Iodine-131 levels reached 7.5 million times the legal limit in a seawater sample taken near the facility.[95]

    [edit] Thursday, 7 April

    Nitrogen injection into the pressure containment vessel of unit 1 was commenced at 01:31.[100]

    A large aftershock, later downgraded from a 7.4 to a 7.1 by USGS, occurred. A tsunami warning was also issued but lifted after 90 minutes. Most of the workers at the nuclear plant were evacuated. TEPCO reported that no further damage to the nuclear plant was detected after this earthquake.[citation needed]

    Official measures at Fukushima I reactor unit 1, however, showed a rise in temperature consecutive to the aftershock and a spiking amount of radiation in the Dry Well which exceeded the instrument maximum of 100 Sv/h.[101] Gauge B, in the meantime, has recorded a steady increase of the pressure for the previous ten days, in the same reactor.[102] Reporting the rise to 100 Sv/h up from the earlier 30 Sv/h TEPCO declared that the "validity of the measurement is questioned" both for radiation levels and pressure.

    [edit] Summary

    [edit] Fifth week

    [edit] Friday, 8 April
    [edit] Saturday, 9 April

    Japan is still struggling to keep water on the reactors to cool them and prevent further meltdown. Russian Antonov An-124 cargo planes flew out of Atlanta and Los Angeles, each carrying a huge concrete boom pump. The two 95-ton boom pumps which TEPCO purchased for $2million each, can be operated from two miles away by remote control. Each boom pump can direct focused streams of water into the damaged reactors.[154]

    Currently TEPCO does not plan to take a Chernobyl approach to resolving nuclear power plant crisis by entombing the radioactive material in concrete.[155] If this decision were to change, the boom pumps could be retrofitted to deliver concrete for that purpose.[154]

    [edit] Monday, 11 April

    Coolant injection into reactors 1 and 3 was interrupted for 50 minutes due to a loss of power after a strong earthquake.[156]

    [edit] Tuesday, 12 April

    Japan officially raises Fukushima to INES Level 7, the same as Chernobyl.[157][158] This new rating considers the accidents as a single event and uses estimated total release to the atmosphere as a justification.[159] At Chernobyl, approximately 10 times the amount of radiation was released into the atmosphere as was released from Fukushima I through April 12, 2011.[160]

    After cooling efforts at spent fuel pool 4 were halted due to an erroneous warning about the pool filling up[161], the temperature of the pool rose to 90 °C and the dose rate 6 meters above the pool spiked at 84 mSv/h.[162]

    [edit] Summary

    Before the crisis evaluation was elevated by Japanese authorities to level 7, the highest level, experts already recognized that Fukushima is the most complicated nuclear accident ever.[163]

    [edit] Sixth week

    Plans were announced for a large-scale study on the environmental and health effects of radioactive contamination from the nuclear plant. Academics and researchers from across Japan will work with the Fukushima Prefectural Government starting in May.[167]

    Nuclear fuel was reported to have melted and fallen to the lower containment sections of three reactors, including reactor three. The melted material was not expected to breach a container (which might cause a massive radiation release). Instead, the melted fuel was thought to have dispersed fairly uniformly across the lower portions of the containers of reactors No. 1, No. 2 and No. 3, which would make the resumption of the fission process, to the extent of a recriticality accident, most unlikely.[168] However, it is only during future dismantling of the three damaged reactors that it would be possible to verify this hypothesis and to know what really occurred inside the reactor cores.

    [edit] Monday, 18 April

    The Associated Press is reporting that two PackBot ground robots from iRobot have entered Unit 1 and Unit 3 of the crippled Fukushima nuclear power plant and performed temperature, pressure, and radioactivity measurements. The remote-controlled robots entered the two reactors over the weekend. The devices opened closed doors and explored the insides of the reactor buildings, coming back with radioactivity readings of up to 49 millisieverts per hour inside Unit 1 and up to 57 millisieverts per hour inside Unit 3. TEPCO officials said that the radiation data from the robots don't change their plans for shutting down the plant by the end of this year. And though more robots will be used, a TEPCO official, Takeshi Makigami, said that robots are limited in what they can do and eventually "people must enter the buildings." [169]

    Test spraying of an "anti-scattering agent" on the ground to prevent further spread of radioactive materials from the site is carried out over an area of about 1200 m2.[170]

    [edit] Tuesday, 19 April

    TEPCO began transferring excess, radioactive cooling water from the reactor No. 2's basement and maintenance tunnels to a waste processing facility.[171]

    [edit] See also

    [edit] Notes

    1. ^ "Magnitude 9.0 – near the East coast of Honshu, Japan". Earthquake.usgs.gov. http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/. Retrieved 17 March 2011. 
    2. ^ IAEA, "Accident Sequence Modelling," p. 3; Wang, John et al. (2000). What Every Engineer Should Know About Risk Engineering and Management, p. 69. at Google Books; excerpt, "... event tree analysis is a major component of nuclear reactor safety engineering".
    3. ^ Josef Oehmen (15 March 2011). "Fukushima Nuclear Accident – a simple and accurate explanation". theenergycollective.com. http://theenergycollective.com/barrybrook/53461/fukushima-nuclear-accident-simple-and-accurate-explanation. Retrieved 15 March 2011. 
    4. ^ "Fukushima faced 14-metre tsunami". World Nuclear News. 23 March 2011. http://www.world-nuclear-news.org/RS_Fukushima_faced_14-metre_tsunami_2303113.html. Retrieved march 24, 2011. 
    5. ^ "In Stricken Fuel-Cooling Pools, a Danger for the Longer Term". New York Times. http://www.nytimes.com/2011/03/15/world/asia/15fuel.html?ref=asia. Retrieved 14 March 2011. 
    6. ^ a b c d "Timeline: Japan power plant crisis". 13 March 2011. http://www.bbc.co.uk/news/science-environment-12722719. Retrieved 15 March 2011. 
    7. ^ "Earthquake Report 2". JAIF. 11 March 2011. http://www.jaif.or.jp/english/aij/member/2011/2011-03-11earthquake2.pdf. 
    8. ^ "Declaration of Nuclear Emergency". Cabinet Secretariat, Cabinet Public Relations Office. http://www.kantei.go.jp/foreign/topics/2011/20110311Nuclear_Emergency.pdf. Retrieved 14 March 2011. 
    9. ^ Gary Anderson (13 March 2011). "Japan earthquake and tsunami: Sea water bid to halt meltdown at Fukushima nuclear plant". mirror.co.uk. http://www.mirror.co.uk/news/top-stories/2011/03/13/sea-water-bid-to-halt-meltdown-at-fukushima-nuclear-plant-115875-22985881/. Retrieved 15 March 2011. 
    10. ^ "Quake Triggers Evacuation of Residents Surrounding Fukushima-1 NPS". JAIF. 11 March 2011. http://www.jaif.or.jp/english/aij/member/2011/2011-03-11earthquake4.pdf. 
    11. ^ a b "Timeline: Japan power plant crisis". BBC News. http://www.bbc.co.uk/news/science-environment-12722719. Retrieved 15 March 2011. 
    12. ^ a b "IAEA Update on Japan Earthquake". IAEA. March 2011. http://www.iaea.org/newscenter/news/tsunamiupdate01.html. 
    13. ^ "Partial Meltdown Possible at Japan Nuclear Plant as Death Toll Estimates Rise to 10,000". Fox News. 7 April 2010. http://www.foxnews.com/world/2011/03/13/partial-meltdown-possible-japan-nuclear-plant-death-toll-estimates-soar/. Retrieved 29 March 2011. 
    14. ^ a b "press release 8". TEPCO. 13 March 2011. http://www.tepco.co.jp/en/press/corp-com/release/11031308-e.html. Retrieved 13 March 2011. 
    15. ^ a b c d e "IAEA Update on Japan Earthquake". http://www.iaea.org/newscenter/news/tsunamiupdate01.html. Retrieved 16 March 2011. "As reported earlier, a 400 millisieverts (mSv) per hour radiation dose observed at Fukushima Daiichi occurred between 1s 3 and 4. This is a high dose-level value, but it is a local value at a single location and at a certain point in time. The IAEA continues to confirm the evolution and value of this dose rate. It should be noted that because of this detected value, non-indispensible staff was evacuated from the plant, in line with the Emergency Response Plan, and that the population around the plant is already evacuated." 
    16. ^ Maeda, Risa (12 March 2011). "Japan rates quake less serious than Three Mile Island, Chernobyl". Reuters. http://www.reuters.com/article/2011/03/12/us-japan-quake-rating-idUSTRE72B2FR20110312. Retrieved 12 March 2011. 
    17. ^ Justin McCurry (14 March 2011). "Explosion at Japanese nuclear plant". The Guardian (London). http://www.guardian.co.uk/world/2011/mar/14/japan-nuclear-explosion-second-reactor-fukushima. 
    18. ^ Tokyo Electric Power Company (14 March 2011). "White smoke around the Fukushima Daiichi Nuclear Power Station Unit 3 (2nd release)". Press release. http://www.tepco.co.jp/en/press/corp-com/release/11031402-e.html. 
    19. ^ [1] Reuters UK 15 March 2011
    20. ^ a b Hiroko Tabuchi, Keith Bradsher, Matt Wald (14 March 2011). "Japan Faces Prospect of Nuclear Catastrophe as Workers Leave Plant". The New York Times. http://www.nytimes.com/2011/03/15/world/asia/15nuclear.html. 
    21. ^ Radiation shoots up at Fukushima nuke plant after blast heard Kyodo News 15 March 2010
    22. ^ "Container damaged, radiation leak feared at Fukushima No.2 reactor". Kyodo News. 15 March 2011. http://english.kyodonews.jp/news/2011/03/78063.html. 
    23. ^ "?????????400???????=?????????????-????" (in Japanese). jiji.com. 15 March 2011. http://www.jiji.com/jc/c?g=soc_30&k=2011031500479. Retrieved 15 March 2011. 
    24. ^ "Radiation levels spike at Japanese nuclear plant". CNN. 15 March 2011. http://edition.cnn.com/2011/WORLD/asiapcf/03/14/japan.nuclear.reactors/index.html?hpt=T1. Retrieved 15 March 2011. 
    25. ^ Black, Richard (16 March 2011). "Japanese emperor 'deeply worried' BBC News". BBC News. http://www.bbc.co.uk/news/science-environment-12762608. Retrieved 23 March 2011. 
    26. ^ Mackey, Robert (14 March 2011). "Latest Updates on Japan's Nuclear Crisis and Earthquake Aftermath - NYTimes.com". Japan: Thelede.blogs.nytimes.com. http://thelede.blogs.nytimes.com/2011/03/15/latest-updates-on-japans-nuclear-crisis-and-earthquake-aftermath-2/?src=twt&twt=thelede#core-group-of-workers-remain-at-plant. Retrieved 18 March 2011. 
    27. ^ CBS/AP (15 March 2011). "Radiation spike hinders work at Japan nuke plant". CBS News. http://www.cbsnews.com/stories/2011/03/15/501364/main20043621.shtml. Retrieved 18 March 2011. 
    28. ^ "Japan suspends work at stricken nuclear plant – Yahoo! News". News.yahoo.com. http://news.yahoo.com/s/ap/as_japan_earthquake. Retrieved 18 March 2011. 
    29. ^ Richard Black (16 March 2011). [–
      { "BBC News – Fukushima workers withdraw after radiation spikes"]. BBC News. –
      {. Retrieved 18 March 2011. 
    30. ^ "Press Release | Transfer of Fukushima Dai-ichi Power Station Workers". TEPCO. http://www.tepco.co.jp/en/press/corp-com/release/11031604-e.html. Retrieved 18 March 2011. 
    31. ^ "Fukushima operator: pouring water into No.5, 6 reactors". Reuters. 16 March 2011. http://www.reuters.com/article/2011/03/16/japan-nuclear-plant-water-idUSTFD00670220110316. Retrieved 18 March 2011. 
    32. ^ "????????????????4????". Yomiuri Shimbun. Japan. http://www.yomiuri.co.jp/feature/20110316-866921/news/20110317-OYT1T00422.htm. Retrieved 23 March 2011. 
    33. ^ "4???????????????????" (in Japanese). Yomiuri Shimbun. 17 March 2011. http://www.yomiuri.co.jp/science/news/20110317-OYT1T00480.htm. 
    34. ^ "??????????????????????" (in Japanese). Yomiuri Shimbun. 16 March 2011. http://www.yomiuri.co.jp/feature/20110316-866921/news/20110317-OYT1T00487.htm. 
    35. ^ Takahara, Kanako, and Alex Martin, "Copters, trucks try to cool fuel rod pool", Japan Times, 18 March 2011, p. 1.
    36. ^ "NHK WORLD English". .nhk.or.jp. http://www3.nhk.or.jp/nhkworld/. Retrieved 18 March 2011. 
    37. ^ "NHK WORLD English". nhk.co.jp. http://www3.nhk.or.jp/daily/english/18_25.html. Retrieved 18 March 2011. 
    38. ^ Takahara, Kanako, and Kazuaki Nagata, "Workers battle against time", Japan Times, 19 March 2011, p. 1.
    39. ^ "More Tokyo firefighters join the battle". NHK. 19 March 2011. http://www3.nhk.or.jp/daily/english/19_11.html. 
    40. ^ ?????????????, Sankei newspaper 19 March 2011
    41. ^ NHK (Evening news broadcast), 19 March 2011, 19:00.
    42. ^ a b c "Stabilisation at Fukushima Daiichi, update 2". World Nuclear News. 20 March 2011. http://www.world-nuclear-news.org/RS_Stabilisation_at_Fukushima_Daiichi_2003111.html. 
    43. ^ "Earthquake Report 15 (Chief Cabinet Secretary's Press Briefing on March 20)". JAIF. 20 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300579753P.pdf. 
    44. ^ "Japan Makes Progress at Nuclear Reactors, but Contamination Spreads". The New York Times. 20 March 2011. http://www.nytimes.com/2011/03/21/world/asia/21japan.html?_r=1. 
    45. ^ http://www.nisa.meti.go.jp/english/files/en20110322-1-1.pdf
    46. ^ "Work to restore power delayed as smoke seen at Fukushima reactors | Kyodo News". English.kyodonews.jp. http://english.kyodonews.jp/news/2011/03/80015.html. Retrieved 23 March 2011. 
    47. ^ http://www.nisa.meti.go.jp/english/files/en20110322-3-1.pdf
    48. ^ Hogg, Chris Stop-start work at Japan reactors BBC News Asia-Pacific, 22 March 2011, 15:44 GMT, retrieved 22 March 2011
    49. ^ Marin, Alex, "All reactors linked to outside power", Japan Times, 23 March 2011, p. 1.
    50. ^ "Press Release | Plant Status of Fukushima Daiichi Nuclear Power Station (as of 11:00 pm Mar 22nd)". TEPCO. http://www.tepco.co.jp/en/press/corp-com/release/11032303-e.html. Retrieved 26 March 2011. 
    51. ^ Coren, Anna "Bottled water scarce after Japan's tap water shown unsafe for infants", CNN, 24 March 1248 HKT, retrieved 24 March 2011.
    52. ^ "Press Release". TEPCO. 24 March 2011. http://www.tepco.co.jp/en/press/corp-com/release/11032412-e.html. 
    53. ^ "press release". TEPCO. 24 March 2011. http://www.tepco.co.jp/en/nu/monitoring/11032413a.pdf. 
    54. ^ Martin, Alex (25 March 2011). "No. 3 cooling pump test-run readied". Japan Times. Japan. p. 1. http://search.japantimes.co.jp/cgi-bin/nn20110325a2.html. 
    55. ^ "3 Japan nuclear workers exposed to radiation". CBS News. 24 March 2011. http://www.cbsnews.com/stories/2011/03/24/501364/main20046609.shtml. 
    56. ^ Maugh II, Thomas H. (24 March 2011). "2 Japanese nuclear workers hospitalized for radiation exposure". LA Times. http://www.latimes.com/news/science/la-sci-japan-workers-exposed-20110324,0,5425809.story. 
    57. ^ a b "2 of 3 radiation-exposed workers suffer internal exposure". Japan. http://english.kyodonews.jp/news/2011/03/81122.html. Retrieved 25 March 2011. 
    58. ^ Tabuchi, Hiroko; Bradsher, Keith; Jolly, David (25 March 2011). "Japan Raises Possibility of Breach in Reactor Vessel". The New York Times. http://www.nytimes.com/2011/03/26/world/asia/26japan.html. Retrieved 25 March 2011. "The injured workers’ dosimeters suggested exposure to 170 millisieverts of radiation. But the institute said that the actual amount of radiation the workers are thought to have been exposed to in the water is 2 to 6 sievert. Even 2 sievert is eight times the 250 millisievert annual exposure limit set for workers at Daiichi." 
    59. ^ "Surface Temps Of Reactors Continue To Fall". NHK. 24 March 2011. http://www3.nhk.or.jp/daily/english/24_53.html. "Reactor temperatures as of 24 March 2011: No 1- 13, No 2- 13, No 3- 11, and No 4- 17 degrees" 
    60. ^ "Reactor Core May Be Breached at Damaged Fukushima Plant". Bloomberg. 25 March 2011. http://www.bloomberg.com/news/print/2011-03-22/nuclear-plant-s-fuel-rods-damaged-leaking-into-sea-tokyo-electric-says.html. Retrieved 25 March 2011. 
    61. ^ "High radiation leak suggests damage to No. 3 reactor vessel". Kyodo. http://english.kyodonews.jp/news/2011/03/80947.html. Retrieved 25 March 2011. 
    62. ^ "Japan reactor core may be leaking radioactive material, official says". Kyodo News Network. Tokyo. 25 March 2011. http://english.kyodonews.jp/news/2011/03/81116.html. Retrieved 25 March 2011. 
    63. ^ "U.S. Navy to Provide 500,000 Gallons of Fresh Water to Fukushima Power Plant". NAVY.mil. 25 March 2011. http://www.navy.mil/search/display.asp?story_id=59318. 
    64. ^ "Japan encourages voluntary evacuations near stricken nuclear plant". CNN. 25 March 2011. http://www.cnn.com/2011/WORLD/asiapcf/03/25/japan.nuclear.disaster/index.html. 
    65. ^ "Radioactive seawater in Japan raises new fears of reactor crack". CSMonitor.com. http://www.csmonitor.com/USA/2011/0326/Radioactive-seawater-in-Japan-raises-new-fears-of-reactor-crack. Retrieved 27 March 2011. 
    66. ^ a b c d "Press Release (Mar 26, 2011) Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:30 am 26 Mar) (TEPCO Press Release)". Tepco.co.jp. http://www.tepco.co.jp/en/press/corp-com/release/11032602-e.html. Retrieved 26 March 2011. 
    67. ^ "Water-laden U.S. barge heading for Fukushima," Yomiuri Shimbun (Japan). 27 March 2011.
    68. ^ "Monitoring data by a monitoring car at Fukushima Daiichi Nuclear Power Station, Measurement Date: 03/26/2011 (TEPCO)" (PDF). http://www.tepco.co.jp/en/nu/monitoring/11032606a.pdf. Retrieved 26 March 2011. 
    69. ^ "Contaminated pools to be drained". World Nuclear News. 27 March 2011. http://www.world-nuclear-news.org/RS_Contaminated_pools_to_the_drained_2703111.html. 
    70. ^ Makinen, Julie; Hall, Kenji (27 March 2011). "Officials retract reports of extremely high radiation at Fukushima plant". Los Angeles Times. http://www.latimes.com/news/la-fgw-japan-radiation-20110327,0,7935538.story. 
    71. ^ "Results of contamination check of water in the Basement at the turbine buildingof each Unit 2 of Fukushima Daiichi Power Station". TEPCO. 29 March 2011. http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110327e15.pdf. 
    72. ^ "Officials: Big spike at Japan nuke plant an error". AP, Yahoo! News. 27 March 2011. http://news.yahoo.com/s/ap/20110327/ap_on_bi_ge/as_japan_earthquake. Retrieved 27 March 2011. 
    73. ^ NAGATA, KAZUAKI. "Radioactive pools block reactor repairs: 1 sievert readings in No. 2 signal fission under way". Japan Times. http://search.japantimes.co.jp/cgi-bin/nn20110327x1.html. Retrieved 27 March 2011. 
    74. ^ Nagata, Kazuaki, "Wild radiation spike in No. 2 proves false", Japan Times, 28 March 2011, retrieved 28 March 2011.
    75. ^ This story was written by Staff Sgt. J.G. Buzanowski. "Yokota AB Airmen play vital role in cooling Fukushima power plant". Af.mil. http://www.af.mil/news/story_print.asp?id=123248837. Retrieved 29 March 2011. 
    76. ^ "Latest Fukushima plant video released". NHK (Japan Broadcasting Company). 27 March 2011. http://www3.nhk.or.jp/daily/english/27_26.html. Retrieved 27 March 2011. 
    77. ^ Nagata, Kazuaki, and Kanako Takahara, "Radioactive water keeps workers out", Japan Times, 29 March 2011, p. 1.
    78. ^ By the CNN Wire Staff. "TEPCO says plutonium found on quake-damaged plant grounds". CNN. http://edition.cnn.com/2011/WORLD/asiapcf/03/28/japan.nuclear.plutonium/?hpt=T2. Retrieved 7 April 2011. 
    79. ^ "Press Release (Mar 28, 2011) Detection of radioactive material in the soil in Fukushima Daiichi Nuclear Power Station". Tepco.co.jp. 28 March 2011. http://www.tepco.co.jp/en/press/corp-com/release/11032812-e.html. Retrieved 7 April 2011. 
    80. ^ Matsutani, Minoru, "Plutonium traces point to core leak", Japan Times, 30 March 2011, p. 1.
    81. ^ "TEPCO chief shows no road map to end nuke accident". NHK WORLD English. 30 March 2011. http://www3.nhk.or.jp/daily/english/30_39.html. Retrieved 7 April 2011. 
    82. ^ "Traces of radioactive iodine found in Washington state milk". http://www.latimes.com/news/nationworld/world/la-fgw-japan-radiation-milk-20110331,0,7944812.story. Retrieved 9 April 2011. 
    83. ^ Takahara, Kanako, and Kazuaki Nagata, "High radiation found outside no-go zone", Japan Times, 1 April 2011, p. 1.
    84. ^ Asahi Shimbun, "TEPCO testing new ways to stop radioactive pollution from Fukushima", 1 April 2011.
    85. ^ a b Pavey, Rob. "SRS pump will head to Japan". Chronicle.augusta.com. http://chronicle.augusta.com/latest-news/2011-03-31/srs-concrete-pump-heading-japan-nuclear-site. Retrieved 7 April 2011. 
    86. ^ a b "Concrete pumps to Fukushima". World-nuclear-news.org. 1 April 2011. http://www.world-nuclear-news.org/RS_Concrete_pumps_to_Fukushima_0104111.html. Retrieved 7 April 2011. 
    87. ^ ????. "?????? : ??62??????? 2011?3?21?". Hk.news.yahoo.com. http://hk.news.yahoo.com/article/110320/3/ncmx.html. Retrieved 7 April 2011. 
    88. ^ http://www.nytimes.com/2011/04/03/world/asia/03japan.html
    89. ^ "Chemical, sawdust, newspaper mix used to plug leak at nuclear plant," Baltimore Sun (US). April 3, 2011, citing CNN, retrieved 2011-04-11.
    90. ^ Two workers' bodies recovered at Fukushima nuclear plant, Los Angeles Times.
    91. ^ [2]
    92. ^ [3]
    93. ^ Japanese nuclear plant continues its radioactive spill into ocean, Los Angeles Times.
    94. ^ http://www.iaea.org/press/?p=1960
    95. ^ a b c Japan nuclear plant operator reports some success on leak, Los Angeles Times.
    96. ^ "Out flow of fluid containing radioactive materials to the ocean from areas near intake channel of Fukushima Daiichi Nuclear Power Station Unit 2," TEPCO Press Release. 6 April 2011, retrieved 2011-04-08.
    97. ^ "IAEA Update (6 April 2011, 8:15 UTC)," retrieved 2011-04-08; "Fukushima leak plugged; nitrogen approved," World Nuclear News (UK). 6 April 2011, retrieved 2011-04-08.
    98. ^ Daily Mail Reporter. "Liquid glass successfully plugs radioactive leak at crippled Fukushima nuclear plant", Daily Mail (UK). April 6, 2011, retrieved 2011-04-08.
    99. ^ Japan defends radical decision to dump toxic water in Pacific
    100. ^ "Plant Status of Fukushima Daiichi Nuclear Power Station (as of 7:00 pm, April 7)". TEPCO. http://www.tepco.co.jp/en/press/corp-com/release/11040709-e.html. Retrieved 7 April 2011. 
    101. ^ "Unit 1 nuclear power plant Fukushima Radiation". TEPCO. http://atmc.jp/plant/rad/?n=1. Retrieved 8 April 2011. 
    102. ^ "Unit 1 nuclear power plant Fukushima Pressure". TEPCO. http://atmc.jp/plant/vessel/?n=1. Retrieved 8 April 2011. 
    103. ^ "Iodine 131 found in groundwater". Japan Times. 1 April 2011. http://search.japantimes.co.jp/cgi-bin/nn20110401x1.html. Retrieved 7 April 2011. 
    104. ^ "Status report: Reactor-by-reactor at the Fukushima Daiichi plant". CNN. 2 April 2011. http://www.cnn.com/2011/WORLD/asiapcf/04/02/japan.nuclear.status/. 
    105. ^ "Gov't eyes injecting nitrogen into reactor vessels to prevent blasts". English.kyodonews.jp. http://english.kyodonews.jp/news/2011/04/82625.html. Retrieved 7 April 2011. 
    106. ^ a b "Absorbent used to soak up radioactive water, 2 found dead at nuke plant". English.kyodonews.jp. http://english.kyodonews.jp/news/2011/04/82827.html. Retrieved 7 April 2011. 
    107. ^ "Radioactive water from Japan nuclear plant leaks in sea". BBC News. 2 April 2011. http://www.bbc.co.uk/news/world-asia-pacific-12945525. Retrieved 7 April 2011. 
    108. ^ "IAEA Briefing on Fukushima Nuclear Accident (2 April 2011, 12:00 UTC)". http://www.iaea.org/press/?p=1908. Retrieved 3 April 2011. 
    109. ^ Makinen, Julie (3 April 2011). "Concrete fails to plug leak at Fukushima nuclear plant". Los Angeles Times. http://www.latimes.com/news/nationworld/world/la-fg-japan-quake-20110403,0,2146668.story. Retrieved 7 April 2011. 
    110. ^ Takahara, Kanako, "Two missing Tepco workers found dead", Japan Times, 4 April 2011, p. 1.
    111. ^ NHK, "Radiation levels gradually decreasing", 3 April 2011.
    112. ^ NHK, "Radiation levels drop or remain flat", 4 April 2011.
    113. ^ Takahara, Kanako, "Tepco dumps toxic water into sea", Japan Times, 5 April 2011, p. 1.
    114. ^ NHK, "Discharge of radioactive water into sea continues", 5 April 2011.
    115. ^ a b Hall, Kenji and Makinen, Julie, "[4]", "Los Angeles Times", 5 April 2011.
    116. ^ a b NHK, "Radioactive water leak at Fukushima plant stops", 6 April 2011.
    117. ^ Rampton, Roberta and Rascoe, Ayesha."[5]" "Reuters", "Japan No 2 core melted through reactor vessel: Rep. Markey", 6 April 2011.
    118. ^ Rampton, Roberta. "NRC says not clear that Japan reactor has melted vessel – Yahoo! News". Ca.news.yahoo.com. http://ca.news.yahoo.com/japan-no-2-core-melted-reactor-vessel-rep-20110406-074109-708.html. Retrieved 7 April 2011. 
    119. ^ Japan nuclear crisis: Workers focus on preventing more hydrogen explosions., Mari Yamaguchi, Huffington Post from AP, April 6, 2011.
    120. ^ http://edition.cnn.com/2011/WORLD/asiapcf/04/07/japan.quake/index.html?hpt=T2
    121. ^ http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0002ksa.php
    122. ^ "IAEA Briefing on Fukushima Nuclear Accident (7 April 2011, 18:00 UTC)". http://www.iaea.org/press/?p=1988. Retrieved 9 April 2011. 
    123. ^ a b c d e "Status of Fukushima Daiichi Nuclear Power Station". http://www.gengikyo.jp/english/shokai/Tohoku_Jishin/status1F.pdf. Retrieved 8 April 2011. 
    124. ^ a b c d "IAEA Briefing on Fukushima Nuclear Accident (7 April 2011, 18:00 UTC)". http://www.iaea.org/press/?p=1988. Retrieved 8 April 2011. 
    125. ^ Makinen, Julie (25 March 2011). "Japan steps up nuclear plant precautions; Kan apologizes". L.A. Times. http://www.latimes.com/news/nationworld/world/la-fgw-japan-nuclear-plant-20110326,0,5763742.story. 
    126. ^ a b c "FAQ 21", L'Institut de radioprotection et de sûreté nucléaire (IRSN, the French "Radioprotection and Nuclear Safety Institute"); retrieved 2011-04-11.
    127. ^ a b c "Seismic Damage Information (the 75th Release) (As of 16:00 April 5th, 2011)". Ministry of Economy, Trade and Industry. 5 April 2011. http://www.nisa.meti.go.jp/english/files/en20110408-1-1.pdf. Retrieved 8 April 2011. 
    128. ^ "Status of nuclear power plants in Fukushima as of 19:00 JST on 16 March". JAIF. 16 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300273535P.pdf. Retrieved 16 March 2011. 
    129. ^ "Status of nuclear power plants in Fukushima as of 09:00 JST on 17 March". JAIF. 17 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300322727P.pdf. Retrieved 17 March 2011. 
    130. ^ "Status of nuclear power plants in Fukushima as of 16:00 JST on 17 March". JAIF. 17 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300322727P.pdf. Retrieved 17 March 2011. 
    131. ^ "Status of nuclear power plants in Fukushima as of 22:00 JST on 17 March". JAIF. 17 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300368041P.pdf. Retrieved 17 March 2011. 
    132. ^ "Status of nuclear power plants in Fukushima as of 10:00 JST on 18 March". JAIF. 18 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300411879P.pdf. Retrieved 18 March 2011. 
    133. ^ "Status of nuclear power plants in Fukushima as of 22:00 JST on 18 March". JAIF. 18 March 2011. http://www.jaif.or.jp/english/aij/110318FukushimaEventStatus-14. Retrieved 18 March 2011. 
    134. ^ "Status of nuclear power plants in Fukushima as of 10:00 JST on 19 March". JAIF. 19 March 2011. http://www.jaif.or.jp/english/aij/110319FukushimaEventStatus-14e.pdf. Retrieved 19 March 2011. 
    135. ^ "Status of nuclear power plants in Fukushima as of 10:00 JST on 20 March". JAIF. 20 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300584349P.pdf. Retrieved 20 March 2011. 
    136. ^ "Status of nuclear power plants in Fukushima as of 22:00 JST on 21 March". JAIF. 21 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300712524P.pdf. Retrieved 21 March 2011. 
    137. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 22 March". JAIF. 22 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300796691P.pdf. Retrieved 22 March 2011. 
    138. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 23 March". JAIF. 23 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300882515P.pdf. Retrieved 23 March 2011. 
    139. ^ "Status of nuclear power plants in Fukushima as of 16:00 JST on 25 March". JAIF. 25 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301041730P.pdf. Retrieved 25 March 2011. 
    140. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 25 March". JAIF. 25 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301056350P.pdf. Retrieved 25 March 2011. 
    141. ^ "Status of nuclear power plants in Fukushima as of 20:00 JST on 26 March". JAIF. 26 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301137974P.pdf. Retrieved 26 March 2011. 
    142. ^ "Status of nuclear power plants in Fukushima as of 10:00 JST on 27 March". JAIF. 27 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301190694P.pdf. Retrieved 27 March 2011. 
    143. ^ "Status of nuclear power plants in Fukushima as of 20:00 JST on 28 March". JAIF. 28 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301311278P.pdf. Retrieved 28 March 2011. 
    144. ^ "Status of nuclear power plants in Fukushima as of 20:00 JST on 29 March". JAIF. 29 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301399277P.pdf. Retrieved 29 March 2011. 
    145. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 30 March". JAIF. 30 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301489625P.pdf. Retrieved 30 March 2011. 
    146. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 31 March". JAIF. 31 March 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301575495P.pdf. Retrieved 31 March 2011. 
    147. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 1 April". JAIF. 1 April 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301659895P.pdf. Retrieved 1 April 2011. 
    148. ^ "Status of nuclear power plants in Fukushima as of 18:00 JST on 2 April". JAIF. 2 April 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301737920P.pdf. Retrieved 2 April 2011. 
    149. ^ "Status of nuclear power plants in Fukushima as of 18:00 JST on 3 April". JAIF. 3 April 2011. http://www.jaif.or.jp/english/aij/member/2011/110403fukushimastatus-59e.pdf. Retrieved 3 April 2011. 
    150. ^ "Status of nuclear power plants in Fukushima as of 21:00 JST on 4 April". JAIF. 4 April 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301918121P-1.pdf. Retrieved 4 April 2011. 
    151. ^ "Status of nuclear power plants in Fukushima as of 20:00 JST on 5 April". JAIF. 5 April 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1302003224P.pdf. Retrieved 5 April 2011. 
    152. ^ "Status of nuclear power plants in Fukushima as of 20:00 JST on 7 April". JAIF. 7 April 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1302175357P.pdf. Retrieved 7 April 2011. 
    153. ^ "Status of nuclear power plants in Fukushima as of 20:00 JST on 8 April". JAIF. 8 April 2011. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1302260293P.pdf. Retrieved 8 April 2011. 
    154. ^ a b Longbottom, Wil. "Massive cargo plane transports £2m remote-controlled concrete pump to stricken Japanese nuclear plant," Daily Mail (UK). 9 April 2011, retrieved 2011-04-11; "World's Largest Concrete Boom Pumps En Route To Japan To Help Cool Nuclear Reactors", The Street (US). April 9, 2011, retrieved 2011-04-11.
    155. ^ "TEPCO won't take Chernobyl approach to resolving nuclear power plant crisis," Mainichi Shimbun (Japan). 8 April 2011, retrieved 2011-04-11.
    156. ^ "Restoration work at Fukushima plant suffers setback in Monday quake". Kyodo News. http://english.kyodonews.jp/news/2011/04/84640.html. Retrieved 11 April 2011. 
    157. ^ "Nuclear accident level raised to maximum". NHK World. 12 April 2011. http://www3.nhk.or.jp/daily/english/12_19.html. Retrieved 2011-04-12. 
    158. ^ "Fukushima Accident Upgraded to Severity Level 7". IEEE Spectrum. April 12, 2011. http://spectrum.ieee.org/tech-talk/energy/nuclear/fukushima-accident-upgraded-to-severity-level-7/?utm_source=techalert&utm_medium=email&utm_campaign=041411. 
    159. ^ "Fukushima Nuclear Accident Update Log". IAEA. 12 April 2011. http://www.iaea.org/newscenter/news/tsunamiupdate01.html. Retrieved 2011-04-13. 
    160. ^ Tran, Mark (12 April 2011). "Nuclear crises: How do Fukushima and Chernobyl compare?". UK: The Guardian. http://www.guardian.co.uk/world/2011/apr/12/japan-fukushima-chernobyl-crisis-comparison. Retrieved 2011-04-13. 
    161. ^ "Japan Plant Emits More Radiation After Cooling Lapse". NTI. http://www.globalsecuritynewswire.org/gsn/nw_20110414_5466.php. Retrieved April 17, 2011. 
    162. ^ "Radiation surges above 4's fuel pool". The Japan Times. http://search.japantimes.co.jp/cgi-bin/nn20110413x1.html. Retrieved April 17, 2011. 
    163. ^ DiSavino, Scott. "Analysis: A month on, Japan nuclear crisis still scarring," Reuters (UK). 8 April 2011, retrieved 2011-04-12.
    164. ^ "Analysis: A month on, Japan nuclear crisis still scarring," International Business Times (Australia). 9 April 2011, retrieved 2011-04-12.
    165. ^ http://www.neimagazine.com/story.asp?sectionCode=72&storyCode=2059373
    166. ^ http://www.neimagazine.com/story.asp?sectionCode=72&storyCode=2059373
    167. ^ "Scholars eye extensive study on nuclear crisis," Tokyo Times (Japan). April 16, 2011, retrieved 2011-04-16.
    168. ^ Japan plant fuel melted partway through reactors: Report, Friday, April 15, 2011.
    169. ^ http://spectrum.ieee.org/automaton/robotics/industrial-robots/robots-enter-fukushima-reactors-detect-high-radiation
    170. ^ "Seismic Damage Information (the 100th Release) (As of 15:00 April 18th, 2011)". TEPCO. http://www.nisa.meti.go.jp/english/files/en20110418-2-1.pdf. Retrieved 18 April, 2011. 
    171. ^ NHK, "Transfer of highly contaminated water begins", 19 April 2011.

    [edit] References

    [edit] External links

    Coordinates: 37°25'17?N 141°1'57?E? / ?37.42139°N 141.0325°E? / 37.42139; 141.0325

    Retrieved from "http://en.wikipedia.org/wiki/Timeline_of_the_Fukushima_I_nuclear_accidents"
    Personal tools
    Namespaces
    Variants
    Actions
    Navigation
    Interaction
    Toolbox
    Print/export
    Languages