Ukraine to build Chernobyl 'cap' to stop radiation leak
26 April 2012 Last updated at 12:14 BST
Twenty-six years after the Chernobyl nuclear disaster, Ukraine is launching the construction of a new protective layer to cover the section of the reactor that exploded.
The disaster, caused by an explosion and fire in the nuclear power station's main reactor, spread clouds of radiation across Europe and forced hundreds of thousands of people to be evacuated.
The BBC's David Stern says the current protective covering is leaking radiation.