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Inside a mine rich in thorium

31 October 2013 Last updated at 12:59 GMT

Experiments in a Norwegian underground plant could lead to the rare earth radioactive element thorium being developed as a safer alternative in the production of nuclear power.

The BBC's Roger Harrabin went to visit a disused iron mine near Ulefloss, Norway, which is rich in thorium. Environmentalist and guide Bard Bergfald gave him a tour.