1 Jul 2020

PUBLICATION NOTICE: Laboratory Simulation of Uranium Metal Corrosion in Different Soil Moisture Regimes

Abstract: A novel laboratory simulation system has been developed for the study of the corrosion of uranium metal in soils. Corrosion and transportation of depleted uranium (DU) as the metal undergoes weathering as a buried material within the soil environment. The corrosion of uranium metal in soil was not well understood due to the gas-liquid-solid phase of the soil. This study presents a novel method to investigate the change of uranium species during the process of process of oxidation of metallic uranium in these environments. Compared with other techniques used for the study of environmental corrosion of metals in soils, this method has the ad-vantage of low secondary uranium pollution, no energy consumption, and ease of operation. The simulation system has been used for the following studies: • Simultaneously simulate the corrosion of uranium metal in different soil moisture regimes • Study the influence of biogeochemical factors on the corrosion of uranium metal • Investigate the change of uranium species during oxidation.

25 Jun 2020

PUBLICATION NOTICE: Rapid Screening for Uranium in Soils Using Field Portable X-Ray Fluorescence Spectrometer : A Comparative Study

Abstract: Depleted uranium armor penetrating munitions are used on testing and training ranges leading to elevated concentrations of U in range soils. To prevent exposure on secure areas contaminated with depleted uranium (DU) hotspots, easy and rapid screening methods are needed. This study explores the feasibility of field portable X-ray fluorescence (FPXRF) spectrometry as a fast screening tool for locating hotspots of DU in the field. Direct comparisons of results were made for U concentrations in soil obtained using a FPXRF spectrometry and measurement of U using ICP-MS after acid digestion. The environmental samples included both field range contaminated soils collected at a munition testing facility and soils spiked with uranium dioxide, uranium trioxide and uranyl nitrate. Using U concentrations measured with ICP-MS from split samples, FPXRF operating procedures and conditions such as analysis time, soil moisture content, sample amount, and sample packing factors were optimized. Results showed that the FPXRF technique yielded similar U concentrations as ICPMS measurements after acid digestion in both standard soil (NIST) samples and DU contaminated range soils. In field contaminated soils, U values with FPXRF were 88.8% of the measurements with ICPMS with a significant correlation (R2: 0.98, n=8). Sample preparation affected the uranium concentration measurements made with FPXRF in the laboratory and in the field. A loose packing of the samples in the sample containers, higher sample occupancy as well as low soil moisture yielded significantly high U concentrations by 4-5%, 15-50% and 43%, respectively. The measured soil U concentrations were not affected by the variation of the sample analysis time. This study suggests that FPXRF is a promising fast screening tool for field DU hotspots as well as detection/location of penetrators in the fields that can increase the ability to rapidly and inexpensively manage DU on ranges and help ensure sustainable use of DU munitions on testing and training ranges.