Measurement of actinide, fission and daughter product contamination in prairie soil

Summary

In 1951, 6.7 liter of an aqueous solution of actinides, fission and daughter products leaked from an underground storage tank into prairie soil. In 2001, soil samples were collected from the site to determine the degree and extent of the contamination. This paper reports on the continuation of complementary analytical techniques used to determine the concentrations of the contaminants in the soil samples, including gamma-ray spectroscopy, neutron activation analysis (NAA) and liquid scintillation counting (LSC). Gamma-ray spectroscopy was able to identify and quantify the presence of ¹³⁷Cs, while the activities of the actinides and remaining fission and daughter products were too low to be measured. Concentrations of ¹³⁷Cs as low as 0.15 Bq/g and as high as 341 Bq/g were measured. NAA was successful in detecting ²³⁸U. Only preliminary LSC analysis has been conducted, resulting in gross beta-counts for the soil samples. Finally, correlations were developed between borehole gamma logging values and corresponding concentrations of ¹³⁷Cs determined by gamma-spectroscopy and gross beta-counts from LSC analysis.