page_title: Japanese reaction to Fukushima Daiichi nuclear disaster
section_title: Meltdowns and radiation
hierarchical_section_title: Japanese reaction to Fukushima Daiichi nuclear disaster / Meltdowns and radiation
caption_attribution_description: English: The Fukushima I Nuclear Power Plant after the 2011 Tōhoku earthquake and tsunami. Reactor 1 to 4 from right to left.한국어: 2011년 토호쿠 대지진 및 쓰나미 뒤에 후쿠시마 원자력발전소(오른쪽에서 왼쪽으로 1호기에서 4호기) Polski: Zniszczenia na terenie elektrowni wywołane trzęsieniem ziemi u wybrzeży Honsiu, tsunami i awarią – zdjęcie satelitarne reaktorów nr 1, 2, 3 i 4 z 16 marca 2011
context_page_description: The Japanese reaction occurred after the Fukushima Daiichi nuclear disaster, following the 2011 Tōhoku earthquake and tsunami. A nuclear emergency was declared by the government of Japan on 11 March. Later Prime Minister Naoto Kan issued instructions that people within a 20 km zone around the Fukushima Daiichi nuclear plant must leave, and urged that those living between 20 km and 30 km from the site to stay indoors. The latter groups were also urged to evacuate on 25 March.
  Japanese authorities admitted that lax standards and poor oversight contributed to the nuclear disaster. The government came under fire for their handling of the emergency, including the slow release of data on areas which were likely to be exposed to the radioactive plume from the reactor, as well as the severity of the disaster. The accident is the second biggest nuclear accident after the Chernobyl disaster, but is more complicated as three reactors suffered at least partial meltdowns.
  Once a proponent of building more reactors, Prime Minister Naoto Kan took an increasingly anti-nuclear stance in the months following the Fukushima disaster.
context_section_description: Nuclear meltdowns at three of Fukushima Daiichi's six reactors went officially unacknowledged for months:
  In one of the most damning admissions, nuclear regulators said in early June that inspectors had found tellurium 132, which experts call telltale evidence of reactor meltdowns, a day after the tsunami — but did not tell the public for nearly three months. For months after the disaster, the government flip-flopped on the level of radiation permissible on school grounds, causing continuing confusion and anguish about the safety of schoolchildren here in Fukushima.
  At 12:33 JST on 13 March the Chief Cabinet Secretary, Yukio Edano, was reported to have confirmed that there was a "significant chance" that radioactive fuel rods had partially melted in Unit 3 and Unit 1, or that "it was 'highly possible' a partial meltdown was underway". "I am trying to be careful with words... This is not a situation where the whole core suffers a meltdown". Soon after, Edano denied that a meltdown was in progress. He claimed that the radioactive fuel rods had not partially melted and he emphasized that there was no danger to the health of the population. Edano later said that there were signs that the fuel rods were melting in all three reactors. "Although we cannot directly check it, it's highly likely happening".
  In April 2011 the United States Nuclear Regulatory Commission said that some of the core of a stricken Japanese reactor had probably leaked from its steel pressure vessel into the bottom of the containment structure, implying that the reactor damage was worse than previously thought. If molten fuel has "left the reactor’s pressure vessel and reached the drywell in substantial quantities, it raises the possibility that the fuel could escape the larger containment structure, leading to a large-scale radioactive release".
  According to the Federation of Electric Power Companies of Japan, "by April 27 approximately 55 percent of the fuel in reactor unit 1 had melted, along with 35 percent of the fuel in unit 2, and 30 percent of the fuel in unit 3; and overheated spent fuels in the storage pools of units 3 and 4 probably were also damaged". The accident has surpassed the 1979 Three Mile Island accident in seriousness, and is comparable to the 1986 Chernobyl disaster. The Economist reports that the Fukushima disaster is "a bit like three Three Mile Islands in a row, with added damage in the spent-fuel stores", and that there will be ongoing impacts:
  Years of clean-up will drag into decades. A permanent exclusion zone could end up stretching beyond the plant’s perimeter. Seriously exposed workers may be at increased risk of cancers for the rest of their lives...
  On March 24, 2011, Japanese officials announced that "radioactive iodine-131 exceeding safety limits for infants had been detected at 18 water-purification plants in Tokyo and five other prefectures". Officials said also that the fallout from the Dai-ichi plant is "hindering search efforts for victims from the March 11 earthquake and tsunami".
  A report from the Japanese Government to the IAEA says the "nuclear fuel in three reactors probably melted through the inner containment vessels, not just the core". The report says the "inadequate" basic reactor design — the Mark-1 model developed by General Electric — included "the venting system for the containment vessels and the location of spent fuel cooling pools high in the buildings, which resulted in leaks of radioactive water that hampered repair work".
  As of July 2011, the Japanese government has been unable to control the spread of radioactive material into the nation's food, and "Japanese agricultural officials say meat from more than 500 cattle that were likely to have been contaminated with radioactive cesium has made its way to supermarkets and restaurants across Japan". Radioactive material has also been detected in a range of other produce, including spinach, tea leaves, milk, and fish, up to 200 miles from the nuclear plant. Inside the 12-mile evacuation zone around the plant, all farming has been abandoned.
  As of Aug
caption: Three of the reactors at Fukushima Daiichi overheated, causing meltdowns that eventually led to hydrogen explosions, which released large amounts of radioactive gases into the air.[61]
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