Abstract: In recent years, with the vigorous development of emerging technologies such as unmanned aerial vehicles (UAVs) and small autonomous underwater vehicles (AUVs), their application scope has become increasingly extensive, and there is a risk of their improper use as a means of illegal intrusion. As important and sensitive facilities, nuclear power plants may currently face multi-dimensional and three-dimensional intrusion risks from the low-altitude, maritime and underwater domains. This paper analyzes the potential risks of new types of threats, identifies the relevant typical scenarios and key performance indicators for prevention, and conducts a comparative evaluation of various detection and countermeasure methods. Based on this analysis, a "Three-Layer and Three-Domain" three-dimensional security system architecture and a phased deployment path are proposed, aiming to provide a reference with quantitative indicators and engineering paths for nuclear power plants to construct a composite and three-dimensional defense system.

Key words: nuclear power plant, low-altitude security, maritime security, three-dimensional defense, technical evaluation