Fukushima Daiichi nuclear disaster

Fukushima Daiichi nuclear disaster. The disaster occurred at the Fukushima Daiichi Nuclear Power Plant, operated by Tokyo Electric Power Company (TEPCO), and was triggered by the 2011 Tōhoku earthquake and tsunami, which affected several nuclear power plants in Japan, including the Fukushima Daini Nuclear Power Plant and the Onagawa Nuclear Power Plant. The incident was rated as a Level 7 event, the highest level on the scale, by the International Atomic Energy Agency (IAEA), and was the largest nuclear accident since the Chernobyl disaster, which was also rated as a Level 7 event. The disaster led to a significant increase in radiation protection measures, including the establishment of the Fukushima Daiichi Decontamination Project by the Japanese government and the United States Department of Energy.

Background

The Fukushima Daiichi Nuclear Power Plant was built in the 1960s and 1970s by General Electric (GE) and Toshiba, with a design based on the Mark I containment system, which was also used at the Three Mile Island Nuclear Power Plant. The plant was located in the Fukushima Prefecture, near the cities of Ōkuma and Futaba, and was operated by Tokyo Electric Power Company (TEPCO), which also operated the Kashiwazaki-Kariwa Nuclear Power Plant and the Fukushima Daini Nuclear Power Plant. The plant had six Boiling water reactor (BWR) units, with a total capacity of 4,696 megawatt (MW) of electric power, making it one of the largest nuclear power plants in Japan, along with the Kashiwazaki-Kariwa Nuclear Power Plant and the Ohi Nuclear Power Plant. The plant was designed to withstand earthquakes and tsunamis, but the 2011 Tōhoku earthquake and tsunami exceeded the plant's design specifications, causing a loss of coolant and a subsequent nuclear meltdown.

Causes and development

The 2011 Tōhoku earthquake and tsunami occurred on March 11, 2011, and was triggered by a megathrust earthquake with a magnitude of 9.0-9.1, which was the largest earthquake in Japanese history, surpassing the 1923 Great Kantō earthquake. The earthquake caused a tsunami with waves reaching up to 14 meters (46 feet) high, which inundated the Fukushima Daiichi Nuclear Power Plant and caused a loss of power to the plant's cooling systems. The plant's emergency core cooling system was activated, but it was unable to cool the reactors sufficiently, leading to a nuclear meltdown in units 1, 2, and 3. The International Atomic Energy Agency (IAEA), the World Health Organization (WHO), and the United States Nuclear Regulatory Commission (NRC) all provided assistance and guidance during the crisis, which was also monitored by the European Nuclear Safety Regulatory Group (ENSREG) and the World Association of Nuclear Operators (WANO).

Release of radioactive materials

The nuclear meltdown at the Fukushima Daiichi Nuclear Power Plant released large quantities of radioactive materials, including iodine-131, cesium-137, and strontium-90, into the environment. The releases were carried by the wind and ocean currents to other parts of Japan, including the Tokyo metropolitan area, and to other countries, including the United States, Canada, and South Korea. The radioactive materials were detected in food products, including milk, meat, and seafood, and in drinking water supplies, leading to concerns about the health effects of the disaster. The World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC), and the National Institute of Environmental Health Sciences (NIEHS) all provided guidance on the health risks associated with the disaster, which was also studied by the National Academy of Sciences (NAS) and the European Commission.

Human impact and evacuation

The Fukushima Daiichi nuclear disaster led to the evacuation of over 100,000 people from the surrounding area, including the cities of Ōkuma and Futaba, and the creation of a exclusion zone around the plant. The evacuation was carried out by the Japanese government, with assistance from the Japanese Self-Defense Forces and the United States military, including the United States Army and the United States Navy. The disaster also had significant economic and social impacts, including the loss of agriculture and fishing industries, and the disruption of education and healthcare services. The United Nations and the Red Cross provided humanitarian assistance to those affected by the disaster, which was also supported by the European Union and the G7.

Environmental impact

The Fukushima Daiichi nuclear disaster had significant environmental impacts, including the release of radioactive materials into the ocean and the atmosphere. The releases contaminated large areas of land and water, including the Pacific Ocean and the Sea of Japan, and affected marine ecosystems, including fish and shellfish populations. The disaster also led to the creation of a dead zone around the plant, where radiation levels were too high for human habitation. The International Atomic Energy Agency (IAEA), the United Nations Environment Programme (UNEP), and the World Wildlife Fund (WWF) all provided guidance on the environmental impacts of the disaster, which was also studied by the National Oceanic and Atmospheric Administration (NOAA) and the European Environment Agency (EEA).

Decontamination and decommissioning

The Fukushima Daiichi nuclear disaster led to a significant effort to decontaminate and decommission the plant, which is expected to take several decades to complete. The effort is being led by Tokyo Electric Power Company (TEPCO), with assistance from the Japanese government and international organizations, including the International Atomic Energy Agency (IAEA), the United States Department of Energy, and the European Commission. The decontamination effort includes the removal of radioactive materials from the plant and the surrounding area, and the decommissioning of the plant's reactors and other facilities. The decommissioning process is expected to involve the removal of nuclear fuel from the reactors, the dismantling of the reactors, and the disposal of radioactive waste. The Fukushima Daiichi Decontamination Project is being supported by the Japanese government, the United States government, and the European Union, and is being monitored by the International Atomic Energy Agency (IAEA) and the World Association of Nuclear Operators (WANO). Category:Nuclear accidents