scission point

In physics, the scission point is the moment when a nucleus breaks into two or more fragments during the process of nuclear fission. This separation is driven by the repulsive Coulomb force between protons within the nucleus, overcoming the attractive nuclear force that holds nucleons together.1

The fission process can be visualized using a liquid-drop model, where the nucleus is treated like a charged liquid drop. As the nucleus deforms, surface tension increases, but the Coulomb repulsion decreases. A barrier in the potential energy exists, and beyond a certain point (the saddle point), the Coulomb force dominates, leading to elongation until the nucleus splits at the scission point. Models suggest that fragment shell structure plays a significant role in determining the outcome of fission.21