Title: The Behavior of Actinide Elements in Contaminated Environments: Applications to Nuclear Forensics

Speaker: Sue B. Clark（Washington State University）

Host: Academician CHAI Zhifang

Time: 10:00, May 9 (Thursday)

Place: Room C305, IHEP Main Building

Abstract:

During the Cold War, the Department of Energy produced large quantities of radioactive materials for defense purposes. These activities resulted in contamination of the natural environment with fission products and actinides. At many locations, low-level radioactive effluents were discharged to unlined seepage ponds for extended time periods, resulting in contaminant migration away from the disposal area. Remediation of these area is needed; however, remedial action requires a thorough understanding of the contaminant behavior in this environment.

In this study, the distribution of contaminants in soils collected downgradient from a seepage basin has been investigated. U, Pu, Am, and Cm have been quantified using radioanalytical and mass spectrometric techniques. The results suggest that there are two sources of U and three sources of Pu in this area. In addition, using published groundwater data, Pu and Cm behavior in the groundwater is proposed. Also, the partitioning of actinides to these soils was studied using sequential extraction. The results indicate a source dependency for actinide partitioning in the soils. This information can be used by remediation engineers to design appropriate cleanup alternatives for the area.

About the speaker:

Sue B. Clark was appointed to the U. S. Nuclear Waste Technical Review Board by President Barack Obama on July 28, 2011.

Dr. Clark is Regents Professor of Chemistry at Washington State University in Pullman, Washington, where she has taught and conducted research in actinide environmental chemistry and radioanalytical chemistry since 1996.

Dr. Clark has served on numerous national advisory committees. From 2009 - 2011, she was a member of the Board of Directors of the U.S. Council for Chemical Research. From 2005 to 2009, she served on the Nuclear and Radiation Studies Board of the National Research Council. From 2004 to 2005, she served on the Board on Radioactive Waste Management of the National Research Council and various study committees for that Board. From 2003 - 2011, she was a member of the Basic Energy Sciences Advisory Committee of the Office of Science, U.S. Department of Energy.

Dr. Clark's awards and achievements include being a fellow of the American Chemical Society, selected in 2010. In 2008, she was Fink Distinguished Lecturer, Georgia Institute of Technology, Department of Chemistry. From 2002 to 2008, she was Westinghouse Distinguished Professor of Materials Science and Engineering at Washington State University.

Professor Clark has published over 100 peer-reviewed papers in environmental chemistry of plutonium and other actinides, chemistry of high-level radioactive waste systems, and actinide radioanalytical chemistry. She is currently serving as an Editor for the journal Radiochimica Acta. Dr. Clark earned a Ph.D. and an M. S. in inorganic/radiochemistry from The Florida State University. She earned a B. S. in chemistry from Lander College in Greenwood, South Carolina.