[en] Since foundation of Nuclear Power Plant Research Institute (NPPRI) in 1977, the department of diagnostics has been dealt with problems related to the theoretical, practical and organizatory questions of operational diagnostics connected with PWR type nuclear components. This department acts directly in locality of NPP Jaslovske Bohunice, but there are performances for all NPP in Slovak or Czech Republic (Dukovany, Mochovce, and Temelin). Besides direct services and achievements for NPP there exist advisory, experts and research activities for the government and supervising authorities, too. In 1985, NPPRI began systematically construct and verify technical means for operational diagnostics of main circulating pumps (MCP) with good results, based on own rich practical experiences and contacts with organisations abroad. In recent years NPPRI as one of recognised qualified and authorised institutions in Slovak Republic has begun to develop a new generation of diagnostic systems for NPP on high technical level but with lower procuring costs in comparison with western countries products. This contribution deals with four following types of diagnostic systems which were not only developed but also delivered and installed on Slovak and Czech nuclear units: - Loose part monitoring system (LPMS), - Humidity monitoring system (HUMON), - Reactor coolant pumps monitoring system (RCPMS), - Primary circuit vibration monitoring system (VMS). Main features of new generation from middle of 1990's of these systems are described in this paper and operational experiences with them too. (author)