Answer: It is nuclear binding energy that holds an atomic nucleus together. Nuclear binding energy is this nuclear force that overcomes the repulsive electrostatic force of the protons, which is acting to try to push the nucleus apart. The nuclear binding energy is created from what is called mass deficit. When an atomic nucleus is fused, all the protons and neutrons in that nucleus give up a small amount of their mass, and this mass is converted into the binding energy that holds the nucleus together. .
