Isotopes of hydrogen used for deuterium and tritium. The IUPAC accepts the D and T symbols, but recommends instead using standard isotopic symbols (H and H) to avoid confusion in the alphabetic sorting of chemical formulas. The ordinary isotope of hydrogen, with no neutrons, is sometimes called "protium". (During the early study of radioactivity, some other heavy radioactive isotopes were given names, H (atomic mass u) is the most common hydrogen isotope with an abundance of more than 99.98%. Because the nucleus of this isotope consists of only a single proton, it is given the formal name "protium". The proton has never been
Tritium penetration of bomb tritium can be separated into 3 distinct layers. Layer 1 is the shallowest layer and includes the deepest, ventilated layer in winter; it has received tritium via radioactive fallout and lost some due to advection and/or vertical diffusion and contains approximately 28% of the total amount of tritium. Layer 2 is below the first layer but above the 26.81 isopycnal and is no longer part of the mixed layer. Its 2 sources are diffusion downward from the mixed layer and lateral expansions outcropping strata (poleward); it contains about 58% of the total tritium. Layer 3 is representative