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.