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Nuclear Accidents by Country 2024

Nuclear energy is highly regarded as a clean and efficient source of power. However, this type of energy generation does come with its own set of risks, as does every type of energy generation, but those risks tend to reap the largest of consequences. A nuclear accident can have truly devastating consequences in terms of both human safety and environmental impact, with some previous accidents continuing to have lasting environmental impacts for decades following the incident. The good news is that nuclear accidents are becoming less and less frequent, with no nuclear accidents occurring in all of 2023.

Major & Notable Nuclear Accidents by Country

The most recent major nuclear accident occurred in Japan in 2011. Known as the Fukushima Daiichi Disaster, this nuclear accident was triggered by a massive earthquake and tsunami which led to a loss of power and cooling systems at the Japanese nuclear power plant in Fukushima Prefecture. This resulted in a reactor melting down and hydrogen explosions damaging several buildings and releasing radioactive material into the environment. The region is still dealing with lasting effects from the fallout.

Other significant nuclear accidents in Japan include a 2007 earthquake that caused a fire, radioactive water leak, and minor radiation release at the Kashiwazaki-Kariwa Nuclear Power Plant in 2007; a fire in the electrical transformer at that same power plant in 2002; and the 1999 Tokai-Mura Criticality Accident in which the mixture of excess uranium in a precipitation tank led to the deaths of two workers with a third seriously injured.

The most notable nuclear accident in any country was the Chernobyl Fallout disaster that occurred in the Ukraine SSR in 1986. This nuclear accident killed about 30 people directly and is estimated will lead to an additional 4,000 cancer-related deaths due to radiation exposure. There was also over $7 billion in property damages. This singular nuclear disaster has had a lasting impact on the use and development of nuclear power plants across the world. The United States in particular increased the monitoring of radiation and instituted a stronger focus on nuclear safety and regulations overnight in reaction to the disaster.

That said, the United States has had its share of nuclear accidents, including chronic radioactive leaks across power plants in the country. For example, Illinois continued to have radioactive waste mishaps at its Exelon nuclear power plants long after the implantation of a 1987 ban on new nuclear power plants.

  • It is likely that additional unlisted, but minor nuclear events have occurred in many locations.
  • Accidents occurring after December 2023 may not be listed.
  • Fatality estimates may skew low, as they often include only deaths from immediate causes, such as explosions or acute radiation exposure, and fail to account for slower-acting health detriments that are nonfatal on their own, but impact quality of life and decrease overall longevity.
  • INES level stands for International Nuclear Event Scale, which measures the severity of nuclear accidents on a scale of 0 (lowest) to 7 (major accident). However, INES ratings are not available for every listed incident.
  • Nuclear incidents vary widely in severity. For example, the 1979 Three Mile Island event saw a reactor reach a partial meltdown state, triggering the evacuation of 150,000 people. By comparison, the 1981 Sequoyah event occurred when mildly radioactive coolant fluid spilled onto 8-14 workers with no ill effects (an event so mild it is left off of many lists of nuclear accidents).

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What country has the most nuclear accidents?

The United States is responsible for the most nuclear accidents in the world.

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