Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86

Valenta, Michelle M. ; Geiszler, Keith N. ; Bjornstad, Bruce N. ; Schaef, Herbert T. ; Brown, Christopher F.

Pacific Northwest National Laboratory (U.S.)

关键词: Leaching;    Waste Retrieval;    Sediments;    Sulfates;    Chlorides;   

DOI  :  10.2172/992384
RP-ID  :  PNNL-18383
RP-ID  :  AC05-76RL01830
RP-ID  :  992384

美国|英语

来源: UNT Digital Library

【 摘 要 】

The overall goals of the Tank Farm Vadose Zone Project, led by Washington River Protection Solutions, are to define risks from past and future single-shell tank farm activities; identify and evaluate the efficacy of interim measures; and aid, via collection of geochemical information and data, the future decisions that must be made by the U.S. Department of Energy (DOE) regarding the near-term operations, future waste retrieval, and final closure activities for the single-shell tank waste management areas (WMAs). To meet the investigative goals of the Tank Farm Vadose Zone Project, the Environmental Sciences Laboratory performed geochemical analyses on vadose zone sediments collected within Waste Management Area C. Tier one analyses of UPR-200-E-86, which includes direct push probe holes C5952, C5958 and C5960, were performed between 3/25/08 and 4/14/08. Preliminary results were presented to CH2M Hill Hanford Group on 6/5/08. As a result of the tier one investigations, further tier two analyses were requested. Tier two investigations include particle size and mineralogy analyses on samples collected between 80 to 120 feet below ground surface that were found to contain high concentrations of chloride and sulfate. Tier one analyses on sediments retrieved near UPR-200-E-81, direct push probe hole C6394, were performed between 6/20/08 and 7/22/08. Preliminary results of the tier one analyses were presented on 8/15/08. As a result of the tier one investigations, further tier two analyses were requested. Tier two analyses include determining whether U-236 exists in samples at approximately 42 feet below the ground surface. Confirmation of U-236 will determine whether the U-238 seen in the leaches performed on samples at that depth is a result of contamination and not from leaching natural uranium. Using the water and acid extract U-238 concentrations from the tier one analysis, equilibrium Kd values were requested to be calculated. Additional tier two analysis includes particle size analysis on samples collected at approximately 135 feet below ground surface to investigate a moist layer containing high chloride and sulfate anion concentrations. Particle size analysis was also requested for a sample collected at approximately 42 feet below ground surface due to its high moisture content and nitrate concentrations. The ESL was also requested to examine Paleosols to determine where the paleosols from the Integrated Disposal Facility would extrapolate to in WMA C.