(N/A) The energy released during a nuclear process is called nuclear energy.
The binding energy per nucleon is almost constant $(8.0 \text{ MeV})$ in the region between $A=30$ to $A=170$ in the figure.
For nuclei in the regions $A<30$ and $A>170$,the binding energy per nucleon is less than $8.0 \text{ MeV}$.
The greater the binding energy,the less is the total mass of a nucleus.
$[\text{Binding energy per nucleon} = \frac{E_{bn}}{A}]$
$\therefore$ Total binding energy of nucleus = (binding energy per nucleon) $\times A$.
If nuclei with less total binding energy transform into nuclei with greater binding energy,there will be a net energy release. As such,there are two types of nuclear processes for obtaining energy:
$1$. Nuclear Fission: When a heavy nucleus decays into two or more intermediate-mass fragments,energy is released. This is the principle of the atom bomb.
$2$. Nuclear Fusion: When two or more light nuclei fuse into a heavier nucleus,energy is also emitted. This is the principle of the hydrogen bomb.
Exothermic chemical reactions lie under conventional energy sources such as coal or petroleum. The energy associated with them is in the range of $\text{eV}$.
In a nuclear reaction,the energy release is of the order of $\text{MeV}$.
Thus,for the same quantity of matter,nuclear sources produce a million $(10^6)$ times more energy than a chemical source.
For example: $1 \text{ kg}$ of uranium generates $10^{14} \text{ J}$ of energy,compared to the burning of $1 \text{ kg}$ of coal,which gives $10^7 \text{ J}$.