Experimental studies of power distribution in LEU-fuel of the IVG.1M reactor

Abstract

For the past ten years, the IVG.1M research reactor has been converted from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Currently, the final stages of the IVG.M reactor conversion, including physical and energy start-ups, are underway. As part of the physical start-up, one of the objectives was to conduct physical studies on the power distribution across the radius and height of the fuel assemblies in 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 or activation products. The ENREDI program was used to determine the detailed relative power distribution over radial cross section of fuel assembly. During these experimental studies, relative power distribution along the height and radial cross section of the IVG.1M fuel assembly, as well as power peaking factors were obtained. These studies will make it possible to evaluate the changes in the IVG.1M reactor fuel power profile after the fuel enrichment reduction, and to verify the accuracy of neutronic simulations.