Irradiation test facilities and loops play a pivotal role in advancing the field of nuclear energy. These systems are engineered to emulate the conditions within nuclear reactors, enabling precise assessment of the performance of nuclear materials and components. They are instrumental in ensuring the safety and reliability of nuclear energy technologies and are crucial for the innovation of new nuclear materials and fuels. Moreover, they are significant in addressing key technical challenges, including material aging and irradiation damage. However, current research on these irradiation test facilities and loops is insufficient. This study aims to conduct an in-depth analysis and comparison of the design characteristics, as well as the advantages and disadvantages, of various irradiation test facilities and loops, including CARR (China Advanced Research Reactor), HFETR (High Flux Engineering Test Reactor), and CMRR (China Mianyang Research Reactor). Additionally, this research includes a thermohydraulic analysis of specific irradiation test loops, deriving thermohydraulic characteristic parameters that are essential for evaluating and ensuring the safety of the test loops under various operating conditions. This further confirms the safety of the test fuel elements, providing a solid foundation for the reliability of the irradiation testing process and the accuracy of nuclear material testing. The results of this study provide a comparative analysis of the design of irradiation test facilities and circuits and provide an important reference for improving their performance and safety.