While Modelica has become a standard for multi-domain modeling in various complex engineering fields, professional and systematic model libraries specifically tailored for the nuclear power sector remain scarce. To bridge this gap, this paper presents the development of a specialized Modelica fluid component library for Small Modular Reactor (SMR) systems. Serving as a critical module within the broader CGN_NHR library, this framework bridges the gap between fundamental fluid mechanisms, equipment-level modeling, and system-level assembly. We detail the library’s architecture, design philosophy, and the mathematical formulation of its core components. To verify its validity and reliability, a systemlevel model was constructed and benchmarked against the industry-standard RELAP5 model. Comparative results confirm that the proposed library offers high efficiency and accuracy, establishing a robust technical foundation for the rapid design, simulation, and verification of nuclear power systems.