Nuclear reactors use and produce very hazardous substances. Radioactive leaks and spillages are not uncommon, often leading to temporary closure of the plants. Accidents can lead to increased danger to people’s health and the environment.

Despite its assurances, the nuclear industry cannot predict every eventuality; accidents can be caused by human or mechanical errors. Each possible accident has the potential to cause global radiation contamination with severe consequences for human health. Below are some of the most well-known disasters.

Windscale (Sellafield), Cumbria, UK, 10th October 1957

One of the two reactors at Britain’s first nuclear plant, used to produce plutonium for Britain’s nuclear weapons programme, caught fire and burned for two days, dispersing poisonous radioactive smoke over Britain, Northern Ireland and northern Europe. Radioactive fallout was identified as far away as Norway, Belgium and Germany.

Demands on the reactor and its staff to produce material for Britain’s first thermonuclear bomb are likely to have contributed to the accident. The disaster was down-played by the British government and the UK Atomic Energy Agency, because of concerns that it would jeopardise plans to collaborate with the US on nuclear weapons research. The full inquiry into the accident was only published 30 years after the event. A re-analysis of the radioactive fallout from the accident was published in 2007 and concluded that twice as much radiation had been emitted than was previously thought. Final decommissioning of the site is still several decades away.

Three Mile Island, Pennsylvania, US, 28th March 1979

A loss of coolant water to a reactor core at the nuclear power plant caused it to partially melt down, releasing radioactive gases into the atmosphere. The reactor had already suffered several breakdowns even though it had only been in operation for three months. After two days, authorities evacuated 3,500 children and pregnant women living within a five mile area. Around 200,000 people fled their homes. How much radiation was dispersed is disputed; the official line is that insignificant amounts were released. However, records were lost, radiation detection equipment may not have worked, and monitors on the vents stacks were said to have been rendered useless by excess moisture. According to the Institute for Energy and Environmental Research, ‘People were exposed to higher doses than were acknowledged’.

A US House of Representatives committee report, published two years later, declared that ‘misleading statements’ about the accident were presented by the managers giving ‘the impression the accident was substantially less severe and the accident more under control than what the managers themselves believed and what was in fact the case.’ The operators of the plant were indicted in 1983 by the US Department of Justice for destruction of safety data and criminal falsification. A distinct lack of research into cancer rates and infant mortality after the disaster has been criticised.

Chernobyl, Ukraine, 26th April 1986

This disaster occurred when a reactor exploded and burned for over a week. Radioactive fallout from this accident was detected over large parts of the world and all over western Europe, especially in Cumbria, Wales and Scotland. Tens of thousands of people had to be evacuated from the surrounding area and hundreds of thousands of deaths and illnesses are likely to have been caused by the radioactive fallout.

Fukushima, Japan, 11th March 2011

An earthquake caused the reactors at the plant to shut down, automatically activating the emergency generators. But the tsunami which followed the earthquake flooded the rooms in which the emergency generator was housed, cutting power to the pumps which circulate cooling water to stop the reactors from over-heating. The explosions which followed released radioactive materials into the atmosphere. At the time, a 12-mile compulsory evacuation zone was designated around the plant with those living closest evacuated and others instructed to stay indoors. About 160,000 people were ordered to move out of their homes. It has still not been deemed safe enough for tens of thousands of people to return to their homes.