Secular equilibrium (source code)

= Secular equilibrium
{wiki=Secular_equilibrium}

Secular equilibrium is a concept in nuclear physics and radiochemistry that describes a situation in a system with multiple radioactive isotopes, where the activity (rate of decay) of a parent isotope is equal to the activity of its daughter isotopes over a long period of time. This occurs when the half-life of the parent isotope is much longer than that of its daughter isotopes.