NUCLEAR CLEANUP — A µSXRF map showing the heterogeneous uranium distribution occurring at the micrometer scale. This and related research is helping learn more about how to clean up contaminated soil at nuclear weapons production sites.

A µSXRF map showing the heterogeneous uranium distribution occurring at the micrometer scale

Accidental releases of liquid waste from U.S. nuclear weapons production facilities have included large quantities of radionuclides, such as cesium, cobalt, europium, strontium, technetium, and uranium. These subsurface leaks at several underground waste storage tanks, first built in the 1940s, have caused complex subsurface contaminant plumes. As a result, many scientific studies have been performed to assess the future of such potentially harmful underground contaminants. One such study, conducted by collaborators from Stanford University, Stanford Synchrotron Radiation Laboratory, Argonne National Laboratory, and Pacific Northwest National Laboratory used a number of techniques coupled to the high-brilliance x-ray beams from XOR beamline 20-ID at the APS and beamline 11-2 at the Stanford Synchrotron Radiation Laboratory to determine the key speciation parameters of uranium in the sediment samples. The researchers concluded that remediation of the contamination at the site they studied would likely be a difficult task because of the speciation and distribution of uranium within the sediments. But they also concluded that future release of uranium from these sediments would be minimal. See: J.G. Catalano, S.M. Heald, J.M. Zachara, and G.E. Brown, Jr., “Spectroscopic and Diffraction Study of Uranium Speciation in Contaminated Vadose Zone Sediments from the Hanford Site, Washington State,” Environ. Sci. Technol. 38 (10), 2822 (2004).

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