Characterization of thorium and uranium contaminated soil from a nuclear fuel facility

This paper describes the utility of soil characterization using electron microscopy to support decontamination efforts of contaminated soil. Soil contaminated with thorium and uranium from the grounds of a nuclear fuel manufacturing facility was subjected to remediation efforts. A light acid leach was able to remove only 30% of the thorium suggesting that the thorium was present in two or more forms. Analytical electron microscopy determined that all of the thorium was present as ThO2, but in a bimodal size distribution and occasionally closely associated with other minerals. Electron microscopy was useful in understanding the remediation data and demonstrates the need for characterization of contaminated soils