Radionuclides in Irradiated Graphite of Uranium-Graphite Reactors: Decontamination of Sleeves Using Liquid Reagents

摘要

To examine the possibility of disposal of irradiated graphite in ground near-surface repositories, the concentration and spatial distribution of radionuclides in the volume of irradiated graphite sleeves of industrial uranium-graphite reactors was studied, and the efficiency of decontamination using liquid reagent treatment methods was evaluated. The radionuclide distribution in the graphite volume is extremely heterogeneous on the 10-100 μm scale. The degree of decontamination using solutions with high acid concentrations and fluoride ions added does not exceed 16-25% for ~(14)C and 15-19% for ~(36)Cl. Under these treatment conditions, no structural changes occur in graphite, and ~(14)C bound with the graphite surface via sorption is removed. Significant differences in the efficiency of the reagent decontamination of irradiated graphite from various producers were revealed.