An untrained but perceptive exclaims, “They say that nuclear energy can be released by sticking nuclei together and by breaking them apart. That doesn’t make sense” Straighten out your friend’s confusion.

Nuclear energy is not released by sticking nuclei together and breaking them apart

Nuclear energy,also called atomic energy,energythat is released in significant amounts in processes that affect atomic nuclei, thedensecores ofatoms

The binding energy per nucleon decreases, as the atomic number increase in heavy nuclei.

So, the intermediate-mass nuclei are at a lower energy per nucleon compared with the heavy-nuclei.

Thus, for heavynuclei to fissile to smaller nuclei, the total energy will decrease, and thus energy s released.

That is why we can break nuclei apart to gain nuclear energy.

For the small nuclei, as the atomic number increase, the binding energy per nucleon increases, thus, the heavier nuclei, like helium, is at a lower energy per nucleon compared to deuterium.

Thus, the fusion of two deuterons to helium$-3$could also produce energy.

That is why we can stick nuclei together to gain nuclear energy.

It is because the behavior of binding energy per nucleon is not monotonic as a function of the atomic number that we can either stick small nuclei together or break big nuclei apart to gain nuclear energy.