Nuclear proliferation Alliance of Nuclear Weapons and Nuclear Power", tritium is not classified as a "special nuclear material" but rather as a by-product. It is seen as an important litmus test on the seriousness of the United States' intention to nuclear disarm. This radioactive super-heavy hydrogen isotope is used to boost the efficiency of fissile materials in nuclear weapons. The United States resumed tritium production in 2003 for the first time in 15 years. This could indicate that there is a potential nuclear arm stockpile replacement since the isotope naturally decays. In May 1995, NPT parties reaffirmed their commitment to a Fissile
Hydrogen isotope biogeochemistry constants would allow extrapolation to original isotopic compositions. While this solution holds promise, there is too much disagreement in the literature for robust calibrations. Vapor isotope effects occur for protium, deuterium, and tritium, because each isotope has different thermodynamic properties in the liquid and gaseous phases. For water molecules, the condensed phase is more enriched while the vapor is more depleted. For example, rain condensing from a cloud will be heavier than the vapor starting point. Generally, the large variations in deuterium concentrations of water are from the fractionations between liquid, vapor, and solid reservoirs. In contrast to the fractionation