The development of a device intended for non-destructive testing of steam generator tubes in a CANDU nuclear power plant is presented in the thesis. In the introductory part, is generally said about nuclear plants. Next, the operating mode of the BWR and PWR nuclear facilities and the CANDU design facility is presented. After that, briefly about steam generators. At the end of the introductory section, the eddy-current method is presented, one of the nondestructive testing methods used in this test. Further, an analysis of the geometry of the calotte of the reference steam generator was made, which also represents the workspace of the manipulator. After analyzing the market and existing products, and developing a functional structure and morphological matrix, two concepts were generated. The first concept was conceived as a stacker manipulator whose ground would be at the bottom of the calotte. Its construction is designed as a two-piece: stand and main part with a manipulator's arm. The second concept is conceived as a manipulator consisting of a main housing with essential parts and a manipulator's arm. The grip would be made on the tube sheet with four pneumatic grippers. After evaluating the concepts according to the set criteria, the second concept was chosen. It has been elaborated and designed in a CAD system. A detailed description of the developed manipulator, its design, as well as the modes of operation of individual systems as well as the manipulator as a whole is made. Furthermore, the calculations used during the manipulator design is presented. At the end of the paper, a schematic of the manipulator operation in the steam generator is shown.