[en] For the past ten years, the IVG.1M research reactor has been converted from HEU fuel to LEU fuel. Currently, the final stages of conversion (physical and energy start-ups of reactor) are being carried out. One of the tasks of physical start-up was to conduct physical studies of power distribution by radius and height of water-cooled technological channels. Studies were carried out using the activation gamma spectrometric method based on correspondence between energy release and measured gamma-radiation activity of fission-products or activation products. Study object was activation of indicators from copper wire and fuel element fragments placed in physical mock-up of technological channels with LEU fuel. ENREDI program, based on polynomial interpolation and approximation methods, was used to determine the detailed (in each fuel elements) relative power distribution by radial cross section of fuel assembly. During these experimental studies, relative power distribution over the height and radial cross section of technological channels of each rows, power peaking factors and value of absolute power were obtained. These studies will make it possible to evaluate changes in power profile in the IVG.1M reactor fuel after reducing of the enrichment, and also to check the accuracy of neutronic simulation. (author)