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Dilapidated building near Chernobyl with a nuclear warning sign

5 worst nuclear disasters from around the world

Nuclear disasters can be caused by a variety of factors, but they all have the potential to have widespread impacts that can linger for generations.


Harnessing the biblical power of nuclear fission was never going to be a risk-free proposition and the world has been shaken by several shocking accidents since the atomic age began. Here are five of the worst.

1. Kyshtym

Decades before the Chernobyl power plant was even built, the Soviet Union experienced a radioactive eruption which irradiated thousands of square miles of the Ural Mountains region. The source of the calamity was the Mayak plutonium-processing plant near the town of Kyshtym – a facility which had been quickly erected to produce essential materials for the Soviet Union’s nuclear weapons programme.

The breakneck pace of development meant safety fell by the wayside, to the point where staff failed to fix a malfunctioning cooling system designed to keep tanks of nuclear waste at safe temperature levels. On 29th September 1957, one of these steel tanks finally exploded, blowing off a metre-thick concrete lid and sending out a cloud of nuclear fallout.

The local population was kept in the dark about the explosion and a whole week went by before they were evacuated. It wasn’t until 1976 that the details of the disaster were leaked to the Western press by an exiled Russian scientist. The true health impact is impossible to know for sure, although increased rates of cancer and other medical issues have been associated with the disaster.

2. Windscale

The name ‘Windscale’ isn’t known to many people these days, because this British nuclear site was renamed 'Sellafield' in 1981. Windscale was then notorious as the site of one of the world’s worst nuclear accidents and the resulting bad PR was a reason why the authorities decided to rebrand.

Back in 1957, Windscale’s towering reactors were producing weapons-grade plutonium for Britain’s nuclear arsenal, but disaster struck in the form of a fire in one of the reactors on 10th October. Workers had to bravely battle to extinguish the inferno, despite the real risk of being irradiated by the burning uranium.

The British government censored the details of what happened and nobody was evacuated from the surrounding area. Research carried out since the fire indicates that the radioactive spillage may have caused up to 240 cancer deaths.

3. Chernobyl

Ironically, the disaster whose name is a byword for nuclear calamity only occurred because of a safety test.

In the early hours of 26th April 1986, workers at the Chernobyl nuclear plant initiated an experiment to assess how the reactor cooling mechanisms would function in the event of a power outage. A combination of design flaws and human error caused the test to go catastrophically wrong, leading to a power surge and a steam explosion which tore the 1,000-ton cover off reactor number four.

Another explosion followed and the reactor was now a terrifying crater expelling radioactive contaminants into the atmosphere. One worker staring directly at the core recounted how the blue, ionised air was ‘flooding up into infinity’ – a spectacle both beautiful and terrifying.

The nearby city of Pripyat was evacuated 36 hours later, abruptly going from a bustling urban centre to an eerie ghost town. Chernobyl workers and firefighters killed by the initial explosions and ensuing radiation poisoning numbered at least 30.

Contrary to popular belief, the three so-called Chernobyl divers who were sent in on a ‘suicide mission’ to drain water from the plant, actually survived their excursion. But the consequences of Chernobyl were immense, with a vast Exclusion Zone being enforced, and the disaster thought to be linked with thousands of cancer deaths.

4. Three Mile Island

Prior to Chernobyl, three words were synonymous with nuclear disaster: Three Mile Island. The incident at this power plant in Pennsylvania on 28th March 1979 was made all the more notorious because it took place less than two weeks after the release of The China Syndrome, a star-studded disaster movie about the imminent threat of a nuclear meltdown.

Although Three Mile Island was fortunately ‘only’ a partial meltdown caused by a cooling malfunction, it was enough to release radioactive materials into the environment. The state’s governor advised that pregnant women and young children should evacuate the area. Before long, around 140,000 people had fled.

Though most experts believe the health effects to have been minimal, Three Mile Island galvanised anti-nuclear activists in the US, with Jane Fonda – star of The China Syndrome – giving a speech at an anti-nuclear protest held in the wake of the accident.

5. Fukushima

The disaster at the Fukushima power plant on 11th March 2011 had the most dramatic origin of all nuclear accidents. Namely, a gigantic tsunami which had been in turn triggered by an undersea earthquake off the coast of Japan.

It was the most powerful earthquake in Japan’s history, and the tsunami waves easily crashed over the plant’s seawall, flooding the reactor buildings and knocking out the emergency diesel generators providing backup power for the coolant systems.

The untamed residual heat within the reactors caused three partial meltdowns and subsequent gas explosions, leading to at least 160,000 people evacuating the area after the accident.

Despite widespread fears about Chernobyl-like consequences, it was later established that the public was not exposed to dangerous levels of radiation. Tragically, it’s widely thought that the vast majority of deaths relating to Fukushima resulted not from the accident itself, but from the frenetic mass evacuations and the impact of this displacement on the elderly and infirm.