Relevance of the research consists in implementation of comparator method k0-standardization of instrumental neutron activation analysis (k0-INAA) when studying at the reactor IVG.1M that will expand the scope of its application. The k0-INAA method is characterized by durability and technological effectiveness at all stages of analysis. When carrying out the investigations the unique experience to adapt the application techniques will be acquired. The main aim of the study is to adapt the k0-INAA to elemental analysis of various materials based on the IVG.1M reactor taking into account the conditions of exposure, physical and technical features of the reactor. The methods used in the study: comparator method of k0-INAA; characterization of irradiation site in experimental channel of IVG.1M reactor; determination of the parameters  and f; selection of optimal irradiation regimes of standard rock samples; preparation and irradiation of rock samples in the experimental channel of IVG.1M reactor; processing and analysis of the experimental data. Scientific novelty. The authors have implemented the comparator method and determined the features of neutron field in the experimental channel of IVG.1M reactor for calculating the concentration of elements by k0-INAA method. The results. The authors determined the concentration of analyte-elements in standard rock sample by k0-INAA method and investigated the fields of thermal and resonance neutrons in IVG.1M reactor. The values of a and f parameters were determined for calculation of concentration by k0-INAA method. The authors defined the content of analyte-elements standard rock samples. The paper introduces the ratios between the calculated and the certified values of element concentrations. The accuracy of analysis is expressed as Z-criterion and evaluated for analyte-elements. For the majority of analytical results Z-criterion values range from 0 to 2. Thus, the results of elemental analysis showed good agreement between the analytical and the certified values of concentration of analyte-elements.