In addition to this instantaneous energy release during the actual fission reaction, there is additional energy released when the fission fragments decay by emission. This additional energy is called decay energy, . The decay chains for rubidium-93 and cesium-140 are shown below.

The energy released during the decay for each chain will be equivalent to the mass difference between the original fission product and the sum of the final stable nuclide and the beta particles emitted.

The energy released in the decay chain of rubidium-93 is calculated below.

The energy released in the decay chain of cesium-140 is calculated below.

The total decay energy is the sum of the energies of the two chains, or 9.73 MeV.