History

Historic Nuclear Accidents

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Accident
Location
Year
INES Level
Cause
Notes
Chernobyl disaster
Pripyat, Ukraine (USSR)19867Reactor test gone wrong, design flawsRBMK reactor 4 exploded, released massive radioactive plume across Europe, 30 direct deaths and thousands of later cancers
Fukushima Daiichi disaster
Okuma, Japan20117Tsunami knocked out coolingTohoku earthquake tsunami flooded backup generators, three reactor cores melted, 150,000 evacuated
Kyshtym disaster
Mayak, USSR19576Cooling failure in waste tankLiquid waste tank exploded at plutonium plant, contaminated 20,000 square km, Soviet cover-up for decades
Windscale fire
Cumbria, UK19575Graphite core fireBritain's worst nuclear accident, released iodine-131 over the UK, milk from nearby farms destroyed
Three Mile Island accident
Pennsylvania, USA19795Partial meltdown, operator errorReactor 2 core partial meltdown, no direct deaths but devastated US nuclear industry and public confidence
Goiania accident
Goiania, Brazil19875Abandoned radiotherapy sourceScavengers broke open cesium-137 capsule from abandoned clinic, 4 deaths, 249 contaminated
SL-1 accident
Idaho, USA19614Prompt critical excursionExperimental US Army reactor exploded during maintenance, killed all 3 operators, only fatal US reactor accident
Tokaimura criticality
Tokaimura, Japan19994Workers mixed too much uraniumFuel plant workers caused criticality accident by bypassing safety procedures, 2 deaths from radiation
Saint-Laurent A1 meltdown
Saint-Laurent, France19694Fuel loading errorFrance's most serious civil nuclear incident, 50 kg of uranium melted inside reactor
Chalk River NRX accident
Ontario, Canada19525Operator errors and valve failuresFirst major reactor accident in history, partial core meltdown, Jimmy Carter helped with cleanup
Lucens reactor accident
Lucens, Switzerland19694Loss of coolant, partial meltdownExperimental underground reactor suffered partial meltdown, cavern sealed for decades
Church Rock uranium spill
New Mexico, USA19790Tailings dam breachLargest radioactive spill in US history, 1,000 tons of waste into Puerco River, largely ignored at the time
Mayak 1967 Lake Karachay
Mayak, USSR19675Dust storm of dried wasteWind picked up radioactive dust from drought-exposed Lake Karachay and contaminated 2,700 sq km
Vinca criticality accident
Vinca, Yugoslavia19584Unintended criticality in research reactor6 researchers irradiated, one died, first bone marrow transplant to treat radiation victims
Buenos Aires RA-2 accident
Buenos Aires, Argentina19834Operator restructured coreOperator caused criticality excursion while reconfiguring fuel, died two days later

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