Radioactivity Revision Notes

Understanding Nuclear Fusion

Nuclear fusion involves the joining of two smaller, positively charged atomic nuclei to create a single, larger, heavier nucleus. This process releases a significant amount of energy, as seen in stars like our Sun. For fusion to happen, the nuclei must approach each other very closely.

The Challenge: Electrostatic Repulsion

Atomic nuclei contain positively charged protons. When these nuclei try to get close enough to fuse, they experience a strong electrostatic repulsive force because like charges repel. This force acts as a barrier, preventing the nuclei from combining unless they have enough energy to overcome it.

Why High Temperatures are Essential

High temperatures mean that the nuclei have very high kinetic energy. This energy allows them to move at extremely high speeds, providing the momentum needed to overcome the electrostatic repulsion and get close enough for the strong nuclear force (which is attractive over very short distances) to take effect and bind them together.

Why High Pressures are Essential

High pressures lead to a greater density of nuclei. With more nuclei packed into a smaller volume, the frequency of collisions between them increases. This increases the probability that nuclei will collide with sufficient energy and at the correct alignment to overcome the electrostatic repulsion and fuse, even given the challenging conditions.