[en] The most important achievements are summed up of the Nuclear Research Institute in Rez in 1984. They are as follows: mobile cementation lines for the disposal of liquid radioactive wastes, completion of the basic line for the reprocessing of spent fuel, reconstruction of the semi-hot cell for the production of thalium ²¹⁰Tl, the dummy experiment on the LR-0 reactor which made it possible to define the effect of neutron dose on the service life of a reactor pressure vessel; research was also carried out related to the nuclear safety of PWR reactors, to reactor physics, technology and materials, the fuel cycle, neutron activation analysis and neutron radiography. In the field of production and services there are research results in the manufacture of radiopharmaceuticals and semiconductor detectors, in standardization and in irradiation, computation and information services. Also mentioned is the fulfilment of the Institute's social programme. (M.D.)