Thorium is a naturally occurring radioactive element found in rocks and soil. It is used as a fuel in some types of nuclear reactors to generate electricity. Full definition
Testing of thorium fuel in the Halden Reactor should be encouraged, taking benefit of the well recognized nuclear fuel competence in Halden. (forskningsradet.no)
Some of them run on thorium fuel rather than uranium. (zdnet.com)
Why aren't we using thorium in nuclear reactors, given the possibility of a meltdown is nearly zero and the waste can not be used to make bombs? (discovermagazine.com)