sentences:  By convention, such heavier elements produced in normal elemental abundance, are "not" referred to as "nucleogenic".Instead, this term is reserved for nuclides (isotopes) made on Earth from natural nuclear reactions.Also, the term "nucleogenic" by convention excludes artificially produced radionuclides, for example tritium, many of which are produced in large amounts by a similar artificial processes, but using the copious neutron flux produced by conventional nuclear reactors.