This lecture covers the fundamentals of nuclear engineering, including reactor technology, nuclear physics, fuel cycle, reactor physics, kinetics, thermal hydraulics, safety principles, accidents, safety systems, waste treatment, radiation protection, and Generation-IV reactors. It emphasizes the importance of safety barriers, redundancy, diversity, and defense-in-depth concepts to prevent and mitigate accidents. The instructor discusses the challenges of decay heat, reactivity control, fuel cooling, and radioactivity confinement. Various safety systems, such as emergency core cooling, containment, and reactor scram, are explained in detail. The lecture also addresses the risks associated with fission reactions, radioactive materials, and the importance of maintaining radiological safety goals.