An approach to molecular characterization of Hanford Site waste tanks

Radioactive wastes from defense operations have been stored at the US Department of Energy's Hanford Site in Washington State since the early 1940s. Over the past 5 decades, much of the waste that has accumulated in these tanks has undergone chemical breakdown because of interaction of chemical constituents with high radiation fields and caustic environments. The radiation fields in the tanks can reach 700 rad/h. In these fields, radiolysis is expected to occur with most organic and aqueous solution in the tanks. Radiolysis can best be compared to a fragmentation of chemicals that produces highly reactive species. These species often can form new molecular species. Radiolysis, coupled with the highly caustic environment of the waste tanks, produces even more mechanisms for formation of various degradation products. Typical degradation products are fragmented organics, hydrogen gas, and various nitrogen oxide gases. This report describes the use of molecular spectroscopy to determine the species present in the tanks