The Fukushima Daiichi Nuclear Disaster: A Decade Later
On March 11, 2011, Japan was hit by a devastating earthquake and tsunami that killed more than 18,000 people and caused widespread damage to homes, infrastructure, and the environment. Among the most severe consequences of the disaster was the meltdown of three reactors at the Fukushima Daiichi Nuclear Power Plant, which released large amounts of radioactive material into the atmosphere and the ocean. It was the worst nuclear accident since the Chernobyl disaster in 1986, and it triggered a global debate on the safety and future of nuclear energy.
What happened at the plant?
The Fukushima Daiichi Nuclear Power Plant, located on the east coast of Japan, had six boiling-water reactors that were built between 1971 and 1979. At the time of the earthquake, only reactors 1 to 3 were operating, while reactor 4 was used for temporary storage of spent fuel rods. The earthquake triggered an automatic shutdown of the reactors, but also damaged the power supply lines to the plant. Without electricity, the cooling systems that were supposed to keep the reactor cores from overheating failed.
About 50 minutes after the earthquake, a massive tsunami wave over 14 meters high breached the sea wall and flooded the plant, knocking out the backup generators and batteries that were supposed to provide emergency power. The plant workers tried to restore power and cool down the reactors using fire trucks and seawater, but they faced multiple challenges such as high radiation levels, explosions, fires, leaks, and debris.
Within days, the fuel rods in reactors 1, 2, and 3 melted partially or completely, creating holes in the bottom of the containment vessels and releasing radioactive gases and water into the environment. Reactor 4 also suffered a hydrogen explosion that damaged its building and exposed its spent fuel pool to the air. The plant operator, Tokyo Electric Power Company (TEPCO), declared a nuclear emergency and evacuated most of its staff from the site.
What were the impacts of the accident?
The Fukushima Daiichi nuclear accident had serious impacts on human health, society, economy, and environment. The Japanese government ordered a mandatory evacuation of about 150,000 people who lived within a 20-kilometer radius of the plant, and advised voluntary evacuation for those who lived between 20 and 30 kilometers away. Many people also left their homes due to fear of radiation exposure or lack of basic services. Some of them have not returned yet.
The radiation released from the plant contaminated large areas of land, water, and air. According to a report by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), about 80% of the radioactive material was deposited in the ocean or dispersed over other countries, while about 20% fell on Japanese territory. The most affected prefectures were Fukushima, Ibaraki, Tochigi, Gunma, Saitama, Chiba, Tokyo, and Kanagawa.
The radiation exposure caused various health problems for the plant workers and the general public. According to a report by the World Health Organization (WHO), about 600 workers received high doses of radiation that increased their risk of developing cancer in the future. About 160 workers received doses that exceeded the annual limit for nuclear workers. The public exposure was lower than that of the workers, but still posed some health risks. The WHO estimated that people in the most affected areas had a slightly higher risk of developing thyroid cancer, leukemia, breast cancer, and other cancers than those in other parts of Japan.
The economic losses caused by the accident were also enormous. According to a report by Japan’s Ministry of Economy, Trade and Industry (METI), the total cost of decommissioning the plant, compensating the victims, decontaminating the affected areas, and disposing of radioactive waste could reach up to 35.5 trillion yen (about $320 billion) by 2051. The accident also affected various sectors such as agriculture, fisheries, tourism, manufacturing, and energy. Many farmers and fishermen lost their livelihoods due to contamination or market restrictions. Many tourists avoided visiting Japan due to fear of radiation or travel disruptions. Many factories had to suspend or relocate their operations due to power shortages or supply chain disruptions. Many consumers had to pay higher electricity bills due to increased reliance on fossil fuels or renewable energy sources.
The environmental impacts of the accident were also significant. The radioactive material released from the plant affected various ecosystems and wildlife, both on land and in the ocean. Some studies have reported changes in
the morphology, physiology, behavior, and genetics of various organisms. For example, some birds showed reduced brain size, lower fertility, higher mutation rates, and increased susceptibility to diseases and predators1 Some insects showed reduced abundance and diversity, especially butterflies that exhibited abnormal wing patterns and coloration. Some plants showed increased rates of growth and reproduction, possibly as a response to stress.
The radioactive material also affected the marine ecosystems and wildlife. According to a report by the Bundesamt für Strahlenschutz (BfS), about 80% of the radioactive fallout was deposited in the ocean or dispersed over other countries. The seawater near the plant was contaminated with high levels of Cs-137, Sr-90, I-131, and other radionuclides that were released from the damaged reactors. These radionuclides were taken up by plankton, algae, fish, and other marine organisms, and accumulated in the food chain. Some studies have reported elevated levels of Cs-137 in fish and shellfish caught near Fukushima and along the coast of Japan. The long-term effects of this exposure on the marine life are still unknown.
What are the current challenges and prospects?
Ten years after the accident, the Fukushima Daiichi Nuclear Power Plant is still undergoing a complex and costly process of decommissioning and cleanup. The main challenges include removing the melted fuel debris from the reactors, managing the large amount of contaminated water stored on site, and disposing of the radioactive waste safely. The Japanese government and TEPCO have estimated that it will take up to 40 years to complete the work, which has already cost Japan trillions of yen.
The recovery of the affected areas and communities is also a long-term endeavor that requires social, economic, and environmental efforts. The Japanese government has lifted the evacuation orders for most of the areas around Fukushima, except for those with high radiation levels. However, many people are reluctant to return to their homes due to health concerns, lack of infrastructure and services, and loss of social ties. The government has also implemented various measures to support the reconstruction of the local industries, especially agriculture and fisheries, which have suffered from contamination and market loss. The government has also promoted renewable energy sources as an alternative to nuclear power, which has faced public opposition and safety issues since the accident.
The Fukushima Daiichi nuclear disaster has been a tragic event that has caused immense suffering and damage to Japan and beyond. However, it has also been an opportunity to learn from the mistakes and challenges, and to improve the scientific knowledge and policy making on nuclear safety and emergency preparedness. The lessons learned from Fukushima can help prevent or mitigate future nuclear accidents, and protect human health and environment from radioactive hazards.
Reference
1: Bundesamt für Strahlenschutz (BfS), “Environmental impact of the Fukushima accident: Radiological situation in Japan”, https://www.bfs.de/EN/topics/ion/accident-management/emergency/fukushima/environmental-consequences.html
2: C. Dong , “The Environmental Impact of the Fukushima Nuclear Power Plant Disaster”, PH241 , Stanford University , Winter 2016.
3: K.O. Buesseler et al., “Fukushima Daiichi–Derived Radionuclides in the Ocean: Transport, Fate, and Impacts”, Annual Review of Marine Science , vol. 9 , pp. 173-203 , 2017.
4: World Health Organization (WHO), “Health risk assessment from the nuclear accident after the 2011 Great East Japan Earthquake and Tsunami based on a preliminary dose estimation”, https://www.who.int/publications/i/item/health-risk-assessment-from-the-nuclear-accident-after-the-2011-great-east-japan-earthquake-and-tsunami-based-on-a-preliminary-dose-estimation
5: Ministry of Economy, Trade and Industry (METI), “Estimation of Total Amounts of Costs Related to Decommissioning, Damage Compensation and Decontamination Work”, https://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20201225_01.pdf
