secular equilibrium
noun1
- The situation of the quantity of a radioisotope remaining constant because it is produced (by decay of a parent isotope) at the same rate that it decays.
- In decay schemes of this type, the following three conditions may predominate: (1) secular equilibrium, (2) transient equilibrium, and (3) the state of no equilibrium. — 1998
forms
secular equilibria · secular equilibriums