Nuclear Reactor Security represents one of the highest levels of strategic protection worldwide due to the sensitivity of these facilities and the potentially catastrophic consequences of any failure or breach, which may extend beyond national borders. A nuclear reactor is not merely an energy facility; it is a convergence point of national security, radiological safety, and environmental stability. Security systems involve multiple layers, including physical protection of the site, surveillance and early detection systems, and cybersecurity measures for control and operational systems. This framework also requires highly trained personnel capable of making precise decisions under extreme pressure and managing complex scenarios involving technical failures or deliberate attacks. The essence of effective security lies in preventing threats before they materialize, not merely responding to them.