Neutron Transport Theory is a mathematical framework used to describe the behavior of neutrons as they move through a medium, such as a nuclear reactor or a shielding material. It focuses on how neutrons interact with matter, including scattering, absorption, and fission processes. This theory helps predict neutron distribution and energy levels, which are crucial for reactor design and safety. The theory is based on the Boltzmann transport equation, which accounts for the changes in neutron density over time and space. By solving this equation, scientists can understand how neutrons propagate and interact, aiding in applications like nuclear engineering and radiation protection.