The Nuclear Shell Model is a theoretical framework used to describe the structure of atomic nuclei. It suggests that protons and neutrons, the building blocks of nuclei, occupy specific energy levels or "shells," similar to how electrons fill energy levels in atoms. This model helps explain the stability of certain isotopes and the behavior of nuclear reactions. In the Nuclear Shell Model, each shell can hold a limited number of nucleons (protons and neutrons), and when these shells are filled, the nucleus becomes more stable. The model also accounts for the effects of spin and angular momentum, providing insights into nuclear properties and phenomena.