Development of Spectroelectrochemical Technetium Sensor for Groundwater Monitoring

The remediation of underground nuclear waste storage tanks and associated disposal cribs and trenches at the U.S. Department of Energy (DOE) nuclear waste storage facilities, together with the associated needs to characterize and monitor the chemical compositions of the contaminants, presents a major scientific challenge. Several of these storage tanks are leaking, and significant quantities of wastes have leaked into the surrounding soil that extends to the vadose zone, which is the unsaturated region above the water table. The major isotopes of concern are 99Tc, 90Sr, 3H (tritium), 137Cs, 60Co, U, Pu, and Am. The danger posed by these radioisotopes entering the water system makes contamination of subsurface water below the vadose zone an urgent problem. Subsurface contamination by technetium is of particular concern for two reasons: the extremely long lifetime of its most common isotope 99Tc and the fast migration in soils of pertechnetate (TcO4), its most chemical forms. A novel spectroelectrochemical sensor will be develop for technetium, in particular pertechnetate, that can be used for in situ ground water monitoring in the vadose zone at the DOE nuclear waste storage tank farms. The sensor that will be developed will employ a preconcentrating polymer for pertechnetate in which a ligand for Tc will be incorporated and where upon reduction of the ligand-Tc complex will produce a luminescent analyte. Commercial Applications and OtherBenefits: The primary market opportunity is for monitoring leakage and migration of Tc into groundwater surrounding nuclear waste storage sites and nuclear fuel reprocessing facilities. Monitoring groundwater at nuclear power plants or where there has been an accident is another potential market for this technology.