<p>The development of nuclear power engineering and the search for improved technical and technological solutions aimed at enhancing its safety necessitate the development and implementation of validated and certified materials (including structural and functional materials). In this context, research reactors play a key role, serving as centers for materials testing and qualification, thereby contributing to the advancement and support of nuclear power engineering. In Kazakhstan, the WWR-K reactor operates as a multipurpose facility, and one of its important applications is the in-pile testing of fuel and materials for advanced nuclear energy systems. For this purpose, the reactor is equipped with additional experimental facilities that enable a wide range of studies to be conducted. The existing experimental infrastructure of the WWR-K reactor has ensured its integration into the international scientific network, making it possible to carry out significant and valuable tests of new structural materials and fuel elements for nuclear energy systems in cooperation with leading international research centers. The present paper describes the experimental infrastructure of the WWR-K reactor that ensures the testing of structural materials under various conditions (temperature, environment, dose, and pressure). Examples of completed reactor irradiation experiments, including those conducted within the framework of international cooperation, are presented, highlighting the uniqueness of the results obtained at both the national and international levels.</p>