[en] The materials with specific properties and their ability to withstand extreme conditions are widely studied in science and engineering. This can be explained by the recent trend towards the increased burn-out of nuclear fuel, longer operation times, and also the increased power and energy intensity of each single unit of nuclear power plants. To this purpose, it is necessary to develop innovative structural materials, because the successful performance of high fuel burnup is limited by the radiation resistance of the cladding and casing materials of fuel assemblies, and also the operational life of thermal reactors is limited by the contents of the vessels and internal materials. Moreover, it is necessary to test the previously-developed materials for their radiation resistance in order to find out not only the limits of their applicability, but also the possibility of using radiation as a technological factor to improve material properties. The materials under intense irradiation may undergo structural transformations, which primarily affect their mechanical properties and corrosion resistance. In this study, the influence of different gamma-irradiation levels on dielectric and mechanical characteristics of fluoro plastic-4MBK was investigated by evaluation of relative dielectric constant, tangent of dielectric loss angle, stress and deformation of the exposed material. (author)