Fukushima nuclear disaster facts for kids
The Fukushima nuclear disaster is a series of ongoing equipment failures, reactor meltdowns, and releases of radioactive materials at the Fukushima Daiichi Nuclear Power Plant, following the Tōhoku earthquake and tsunami on March 11, 2011. The plant has six separate Nuclear reactors maintained by the Tokyo Electric Power Company (TEPCO). The accident is the second biggest nuclear accident after the 1986 Chernobyl disaster, but more complex as all reactors are involved.
At the time of the quake, reactor 4 had been de-fueled while 5 and 6 were in cold shutdown for planned maintenance. The remaining reactors shut down automatically after the earthquake, but the entire plant was flooded, including low-lying generators and electrical switchgear in reactor basements and external pumps for supplying cooling seawater. The connection to the electrical grid was broken. All power for cooling was lost and reactors started to overheat. There was a partial core meltdown in reactors 1, 2, and 3; hydrogen explosions destroyed the upper part of the buildings housing reactors 1, 3, and 4; an explosion damaged the containment inside reactor 2; fires broke out at reactor 4. Despite being initially shutdown, reactors 5 and 6 began to overheat. Spent nuclear fuel rods stored in pools in each reactor building overheated as water levels in the pools dropped.
Fears of radiation leaks led to a 20 km (12 mi) radius evacuation around the plant while workers suffered radiation exposure and were temporarily moved out at various times. Grid power was restored to parts of the plant on 20 March, but machinery for reactors 1 through 4, damaged by floods, fires and explosions, was still not working. Flooding with radioactive water through the basements of units 1–4 continues to prevent access to carry out repairs. Measurements in areas of northern Japan 30–50 km from the plant showed radioactive caesium levels high enough to cause concern. Food grown in the area was banned from sale. It was suggested that worldwide measurements of iodine-131 and caesium-137 indicate that the releases from Fukushima are of the same order of magnitude as the releases of those isotopes from the Chernobyl disaster in 1986;
Tokyo officials said that tap water should not be used to prepare food for children. Plutonium contamination has been detected in the soil at two sites in the plant. Two workers hospitalized as a precaution on 25 March had been exposed to between 2000 and 6000 mSv of radiation at their ankles when standing in water in unit 3. Radiation levels varied widely over time and location.
The nuclear emergencies at Japan's Fukushima I and other nuclear facilities raised questions about the future of nuclear power. Platts, an energy news website, said that "the crisis at Japan's Fukushima nuclear plants has prompted leading energy-consuming countries to review the safety of their existing reactors and cast doubt on the speed and scale of planned expansions around the world". Following the Fukushima nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.
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Images for kids
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Cross-section of a typical BWR Mark I containment as used in units 1 to 5. RPV: reactor pressure vessel DW: drywell enclosing reactor pressure vessel. WW: wetwell – torus-shaped all around the base enclosing steam suppression pool. Excess steam from the drywell enters the wetwell water pool via downcomer pipes. SFP: spent fuel pool area SCSW: secondary concrete shield wall
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The height of the tsunami that struck the station approximately 50 minutes after the earthquake. A: Power station buildings B: Peak height of tsunami C: Ground level of site D: Average sea level E: Seawall to block waves
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Aerial view of the station in 1975, showing separation between units 5 and 6, and 1–4. Unit 6, not completed until 1979, is seen under construction.
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Unit 4 after the hydrogen explosion. The bright yellow object is the reactor's removed Primary Containment Vessel head or drywell lid. The removed large black Reactor Pressure Vessel head with its lifting frame attached is to the left. Both had been removed to allow refueling at the time. The green object is the crane for the spent fuel pool.
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The Fukushima No.1 reactor control room in 1999
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Map of contaminated areas around the plant (22 March – 3 April 2011)
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Radiation measurements from Fukushima Prefecture, March 2011
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Radiation hotspot in Kashiwa, February 2012
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Comparison of radiation levels for different nuclear events
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The town of Namie (population 21,000) was evacuated as a result of the disaster
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IAEA team examining Unit 3
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Protest against nuclear power in Berlin, Germany, March 2011
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The number of nuclear power plant constructions started each year worldwide, from 1954 to 2013. Following an increase in new constructions from 2007 to 2010, there was a decline after the Fukushima nuclear disaster.
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Part of the Seto Hill Windfarm in Japan, one of several windfarms that continued generating without interruption after the 2011 earthquake and tsunami and the Fukushima nuclear disaster
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Price of PV modules (yen/Wp) in Japan
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Anti-nuclear power plant rally on 19 September 2011 at the Meiji Shrine complex in Tokyo
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Japan towns, villages, and cities in and around the Daiichi nuclear plant exclusion zone. The 20 and 30 km (12 and 19 mi) areas had evacuation and shelter in place orders, and additional administrative districts that had an evacuation order are highlighted. However, the above map's factual accuracy is called into question as only the southern portion of Kawamata district had evacuation orders. More accurate maps are available.
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IAEA experts at Unit 4, 2013
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Evacuation flight departs Misawa
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Protest against nuclear power in Cologne, Germany on 26 March 2011
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See also
In Spanish: Accidente nuclear de Fukushima I para niños
