A radioactive isotope of hydrogen (one proton, two neutrons). Because it is chemically identical to natural hydrogen, tritium can easily be taken into the body by any ingestion path. It decays by beta emission. It has a radioactive half-life of about 12.5 years.
TRITIUM
Meaning of TRITIUM in English
NRC Nuclear Energy English Glossary. Английский глоссарий ядерной энергии NRC (Национальный научно исследовательский совет). 2012