How a cheap drone punctured Chernobyl's 40K tonne shield

Eric Schmieman worked for 15 years on the modern engineering equivalent of the Great Pyramid — building a giant protective shield for a damaged reactor at Chernobyl that would protect the world from further fallout from the worst ever nuclear disaster.

- KIM BARKER

The steel shell, slid into place over reactor no. 4 on railroad tracks in 2016, is the world's largest movable structure. It is as tall as a football field and weighs almost 40,000 tonnes. More than 45 countries and organisations spent almost $1.7 billion building it.

"We did a lot of safety analysis, considering a lot of bad things that could happen," said Schmieman, 78, a retired civil engineer from Washington state who was a senior technical adviser on the project.