What is meant by fertile material?
There are certain nuclides of elements with a high atomic weight that react with neutrons by capturing them and subsequently emitting beta particles, resulting in an end nuclide that is fissionable. These initial non-fissionable nuclides are of enormous practical interest, because if they are used in a nuclear reactor, they serve as raw material for obtaining nuclear fuel. They are called fertile nuclides and the material containing them is called fertile material. Thorium 232 and U-238 are the two major fertile isotopes. Therefore, natural depleted thorium and uranium are the two most important fertile materials from a technical point of view.
