Hydrogen3

Hydrogen-3, commonly called tritium, is a radioactive isotope of hydrogen with mass number 3. It consists of one proton and two neutrons in the nucleus. Tritium decays by beta-minus emission to helium-3, with a half-life of 12.32 years. The emitted beta particle has a maximum energy of 18.6 keV. External exposure from tritium is largely minimal due to its low-energy emission, but internal exposure from inhalation, ingestion, or incorporation into organic compounds can pose radiological hazards.

Tritium occurs naturally in the atmosphere as a product of cosmic ray interactions and is found in trace amounts in water and biological systems. For practical use, it is produced in nuclear reactors and particle accelerators, primarily through neutron activation of lithium-6 (Li-6(n, alpha)T). It can also be generated by spallation in high-energy facilities and is collected in various chemical forms for handling.

In chemistry, tritium behaves similarly to the other hydrogen isotopes, forming molecular species such as HT, T2, and incorporating into compounds to give tritiated water (HTO or T2O). Its physical properties are close to those of protium, with differences arising from the increased mass. Because of its radioactivity, tritium is primarily used as a tracer in research and industry.

Major applications include hydrological and biomedical tracing, groundwater dating, and as a fuel component in controlled fusion reactions (often in mixtures with deuterium for D–T fusion). Tritium is also used in self-luminous devices, where sealed glass tubes containing tritium gas illuminate phosphor coatings without external power.

Safety and regulation: Handling and release are tightly regulated to limit internal exposure and environmental contamination. Standards are enforced by national and international agencies, with monitoring and strict containment for research, energy, and industrial uses.