But what actually happened on that devastating day in 1986 and, crucially, in the aftermath?
- The cause of the accident, which occurred at reactor 4, was a combination of poor design and human error during a safety test. Operators ran the plant at low power without taking the correct precautions. The reactors were highly unstable at low power.
- There were two explosions. A power surge caused a sudden increase in heat, which ruptured tubes containing fuel. Hot fuel particles then reacted with the cooling water, causing a steam explosion that lifted the 1,000-ton cover off the top of the reactor. A second explosion exposed the reactor core to the environment and a fire that burned for 10 days released radiation into the atmosphere.
- The disaster took place in the Ukraine, then part of the Soviet Union, and affected Belarus, Ukraine, and Russia. Today the Exclusion Zone covers an area of approximately 2,600km² and has become a tourist attraction.
- The nearest human settlement to the power plant was the newly-built city of Pripyat, which had a population of about 50,000 people. Soviet authorities started evacuating around Chernobyl within 36 hours of the accident. They evacuated 115,000 people following the incident in 1986 and a further 220,000 after that.
- After the accident, authorities enclosed reactor 4 in a concrete structure that broke down over time. It’s now encased in an enormous steel “sarcophagus” that should last 100 years.
And if you happen to be on holiday in Kiev, Ukraine, you can take a day trip to the Chernobyl Exclusion Zone.
We’re not sure you’ll want to after seeing these images ...