Big data is a term used for a wide variety of large data that require high processing speed. Big data handling includes not only the data, but also data collection, transmission, storage, processing (conversion, calculation, analysis), visualization and use of information in various areas of human activities. The emergence of Big data is one of the steps to digitizing all information used in different spheres. In recent years, Big data are used in foreign countries in a number of industries, including nuclear energy. It can be assumed that the Big data use in the coming years may become the next revolutionary introduction of digital technologies for NPPs. The paper provides examples of using the Big data in various countries to create new units and improve operating units. The areas of Big data use in the operation of Ukrainian NPPs are as follows: -   in intended creation of an industrial system for technical diagnostics of systems, structures and components of NPPs; -   for improving activities on long-term operation of power units; -   for improving safety becouse of using of information based on Big data: structured information on equipment failures and incidents at different NPPs stored in international and national databases; information obtained from drones, in particular in post-accident monitoring, etc.

The Kharkiv Subsidiary of the State Enterprise “Scientific and Technical Center for Nuclear and Radiation Safety” (SSTC NRS) started its history on 12 April 1993 with the establishment of the NPP I&C Reliability Analysis Department in Kharkiv within the back then Scientific and Technical Center for Nuclear and Radiation Safety (STC NRS). The author of the paper tells about the history of the Kharkiv Subsidiary, areas of activities, obtained results and prospects for the development.