On April 26, 1986 at 1.23 am technicians at the Chernobyl Nuclear Power Station in Ukraine allowed the power in reactor number 4 to fall as part of a routine test. To carry out their tests, they de-activated several major safety systems that should have shut down the reactor in an emergency.

A sudden surge of power caused an emergency shutdown to be performed leading to a more extreme spike and a series of explosions. The events exposed the graphite moderator to air causing it to ignite. The explosions blew the 200 tonne roof off the reactor building and a fire started in the core which burned for several days. A cloud of deadly radio active particles dispersed into the surrounding environment. This silent killer continued to pour from the damaged reactor for ten days. Over 60% of it fell on Belarusian territory. Some of these highly carcinogenic radioactive particles have an half life of 24,000 years.

Even now, over 30 years later, official warnings against eating wild foods contaminated by Chernobyl’s fallout still exist in these countries. But the worst consequences of this tragedy are the thousands of thyroid cancers and leukemia in Ukraine and Belarus, and the tens of thousands more predicted cancers of all types over the next 50 or 60 years. These, together with the vast areas of radioactively contaminated and uninhabitable land, and the humanitarian crises which afflicted Ukraine and Belarus shows that a worst-case nuclear disaster really can (and did) happen.