This lecture covers the physics of nuclear reactors, including basic principles, reactor modeling, neutron diffusion, moderation, lattice physics, and advanced technologies. It delves into specific reactor types like RBMK and CANDU, discussing their advantages, disadvantages, and historical accidents like Chernobyl. The instructor also explores liquid-fuel reactors, molten salt reactors, and the thorium fuel cycle, highlighting their design, fuel options, and operational characteristics.