X-ray structural and physical and mechanical studies of uranium-graphite fuel (IGR reactor)

Abstract

The pulsed graphite reactor (IGR) is one of the oldest research reactors in the world. Since 1968, graphite with impregnated uranium with an enrichment of 90% in 235 uranium has been used as a fuel for the IGR reactor. Current conditions require the end of the use of highly enriched uranium (HEU) as fuel in research reactors, as this contradicts the concept of technologies resistant to the proliferation of nuclear weapons. For this reason, for more than two decades, international measures have been taken to phase out the use of HEU in research reactors by converting these plants to low enriched uranium fuel (LEU). This determines the relevance of research.Material science studies were conducted to determine the properties of non-irradiated fuel of high enrichment, which are important for the transportation of fuel and its subsequent dilution. Research LEU fuel was conducted in order to obtain information about the properties for comparison with the properties of HEU fuel. One of the tasks is to compare the X-ray structural and physicomechanical characteristics of HEU and LEU fuel in order to make a decision on replacing fuel cells while maintaining the energy release, power and stability of the IGR reactor.The paper presents the main results of material science research, the emphasis is on the analysis of x-ray structural and strength characteristics of uranium-graphite fuel. X-ray structural characteristics were determined by x-ray diffraction. Strength characteristics were established by determining the compressive strength.Significant results were obtained on the X-ray structural and physicomechanical characteristics of the high-enrichment IGR fuel material.X-ray structural characteristics (interlayer distance, degree of graphitization, x-ray density, texturing coefficient) and physicomechanical properties (ultimate compressive and deformation strength at maximum load) HEU of the IGR reactor fuel were determined for the first time. Research is important and can be applied in the design of fuel cells of uranium-graphite reactors.