Mercury Phase II Study - Mercury Behavior across the High-Level Waste Evaporator System

Analysis of Ionic Mercury Species in SRR Samples Measured by SRNL and Eurofins FGS

“…2 The use of mercuric ions continues today in the nuclear material processing facilities for the dissolution of various aluminum-based materials. 3 Fourth quarter CY2014 samples from Tank 50 showed relatively high levels of total and organomercury, at approximately 76 and 25 mg/L, respectively, relative to the formation mechanisms predicted by models and leachate testing. 1…”

Evaluation of the Current State of Knowledge for Thermolysis of Organics within SRS Waste Forming Volatile Organic Compounds (VOCs)

“…Organo-mercury compounds have been identified in SRS Tank Farm samples in recent studies. 40,41,42,43,44 Methyl mercury is confirmed present in Tank 50 supernate at concentrations up to 60 mg/L. 42 Both dimethyl mercury and ethyl mercury are typically below 1 mg/L; for instance, the 3 rd quarter 2017 Tank 50 supernate showed < 0.17 mg/L Hg as ethyl mercury and 0.062 mg/L Hg as dimethyl mercury.…”

“…40 Methyl mercury has been measured in the range of 2.5 to 200 mg/L in samples from the SRS 2H Evaporator tanks with detectable dimethyl mercury values in the range of 8.9E-04 to 0.6 mg/L. 42,44 Formation of dimethyl mercury in simulated SRS waste tank solutions has been studied in the temperature range of 40 °C to 80 °C. 45 One of the findings of that work indicates that alkaline waste solutions containing organics such as acetate and antifoam agent polydimethylsiloxane can rapidly methylate all of the Hg(II) present in solution to methyl mercury, and then, more slowly over time generate dimethyl mercury.…”

Methylmercury and Ethylmercury Analytical Performance in SRR Samples Measured by SRNL and Eurofins Frontier Global Sciences

“…However, a variety of work over the past four years has demonstrated that there is a much greater variety of mercury species in the SRS liquid waste system. [1][2][3][4][5][6] Quarterly analyses of Tank 50 samples were the first to show that mercury is present as organomercurial species. Methylmercury has been shown to leach from the saltstone waste form at concentrations that may present challenges to its remediation and disposition.…”

“…4. Each of the green diamonds on these plots provides a 95% confidence interval for the mean of the corresponding grouping of these measurements.…”