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Nuclear Safeguards Education Portal


Photo related to the term with caption below

Monazite, a rare-earth-and-thorium phosphate mineral, is the primary source of the world's thorium

(Source: United States Geological Survey)

A radioactive element with atomic number 90 and symbol Th. Naturally occurring thorium consists only of the fertile isotope 232Th, which through transmutation becomes the fissionable 233U.