Evaluation of Cement Waste Form for Final Disposal of Uranium Contained Wastes

The operation and decommissioning of nuclear facilities generates uranium-containing waste. It is important to note that significant quantities of uranium-contaminated soil may be generated from uranium-contaminated ground surfaces. Furthermore, uranium deposits may also be generated from the decontamination of uranium-contaminated soil. These particulate radioactive waste can be disposed of through a non-dispersive immobilization process, such as cementation. In this study, cement-solids were prepared under different mixing ratios for uranium-contaminated soil and uranium deposits. The cement solids were evaluated for workability, free water, and stability. The cement solidification of uranium-contaminated soil achieved a maximum waste loading of 30wt% with a compressive strength of 16.607 MPa. Uranium precipitates containing about 40wt% diatomite were immobilized in a cement matrix at a maximum loading of 20wt%, achieving a compressive strength of 3.83 MPa. Cement solidification of uranium precipitates, mainly composed of U and Fe, achieved a maximum waste loading of 30wt% with a compressive strength of 7.12 MPa. The results of this study are expected to support the selection of conditions for the solidification of uranium waste.