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

Abstract

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 betweenmore » 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.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
992384
Report Number(s):
PNNL-18383
830403000; TRN: US1007931
DOE Contract Number:
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ANIONS; CHLORIDES; CLOSURES; CONTAMINATION; LEACHING; MINERALOGY; MOISTURE; NATURAL URANIUM; NITRATES; PARTICLE SIZE; PROBES; SEDIMENTS; STORAGE FACILITIES; SULFATES; TANKS; WASTE MANAGEMENT; WASTE RETRIEVAL

Citation Formats

Valenta, Michelle M., Geiszler, Keith N., Bjornstad, Bruce N., Schaef, Herbert T., and Brown, Christopher F. Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86. United States: N. p., 2009. Web. doi:10.2172/992384.
Valenta, Michelle M., Geiszler, Keith N., Bjornstad, Bruce N., Schaef, Herbert T., & Brown, Christopher F. Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86. United States. doi:10.2172/992384.
Valenta, Michelle M., Geiszler, Keith N., Bjornstad, Bruce N., Schaef, Herbert T., and Brown, Christopher F. Wed . "Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86". United States. doi:10.2172/992384. https://www.osti.gov/servlets/purl/992384.
@article{osti_992384,
title = {Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86},
author = {Valenta, Michelle M. and Geiszler, Keith N. and Bjornstad, Bruce N. and Schaef, Herbert T. and Brown, Christopher F.},
abstractNote = {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.},
doi = {10.2172/992384},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Apr 01 00:00:00 EDT 2009},
month = {Wed Apr 01 00:00:00 EDT 2009}
}

Technical Report:

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  • Letter report prepared for analytical results for CHG
  • Leakage of underground tanks containing high-level nuclear waste solutions has been identified at various DOE facilities. The Hanford Site is one the main facilities of concern, with about 2,300 to 3,400 m3 of leaked waste liquids. Radionuclides and other contaminants have been found in elevated concentrations in the vadose zone and groundwater underneath single shell tank farms. We do not currently know the mechanisms responsible for the unexpected deep migration of some contaminants through the vadose zone, and such understanding is urgently needed for planning remediation. Due to the extreme chemical conditions of the tank waste solutions (very high pH,more » aluminum concentration, and ionic strength), interactions between the highly reactive waste solutions and sediments underneath the tanks can result in dissolution of primary minerals of the sediments and precipitation of secondary phases including colloidal particles. Contaminants can sorb onto and/or co-precipitate with the secondary phases. Therefore transport of strongly associated contaminants on mobile colloids can be substantially greater than without colloids. The overall objective of this research is to improve our understanding on the effects of interactions between the tank waste solution and sediments on deep contaminant migration under Hanford Site conditions. This objective will be achieved through the following four tasks: (1) colloid generation and transport studies, (2) studies on sediment permeability and chemical composition alterations, (3) quantifying associations of contaminants with secondary colloids, and (4) studies on the combined effects of the aforementioned processes on deep contaminant migration.« less
  • The Hanford Site was one of the DOE's major nuclear weapons production sites from 1940 to 1989. Over time, 67 of the 149 single-shell tanks have leaked or are suspected of having leaked [1]. Contaminants such as 99Tc and U have been found in elevated concentrations in the vadose zone and groundwater beneath the single shell tank farms [2]. In order to make decisions on remedial actions, numerous scientists have been investigating these problems through the DOE's Environment Management Science Program Hanford Vadose Zone Project. The U.S. Department of Energy has on-going projects at the Hanford site to monitor existingmore » contaminant plumes in groundwaters, and to characterize the subsurface distribution of contaminants in tank farms. These efforts include the Tank Farm Vadose Zone Characterization Project and the 200 Area Remedial Action Project.« less
  • A geologic/geochemical investigation in the vicinity of UPR-200-E-82 was performed using pairs of cone-penetrometer probe holes. A total of 41 direct-push cone-penetrometer borings (19 pairs to investigate different high moisture zones in the same sampling location and 3 individual) were advanced to characterize vadose zone moisture and the distribution of contaminants. A total of twenty sample sets, containing up to two split-spoon liners and one grab sample, were delivered to the laboratory for characterization and analysis. The samples were collected around the documented location of the C-152 pipeline leak, and created an approximately 120-ft diameter circle around the waste site.more » UPR-200-E-82 was a loss of approximately 2,600 gallons of Cs-137 Recovery Process feed solution containing an estimated 11,300 Ci of cesium-137 and 5 Ci of technetium-99. Several key parameters that are used to identify subsurface contamination were measured, including: water extract pH, electrical conductivity, nitrate, technetium-99, sodium, and uranium concentrations and technetium-99 and uranium concentrations in acid extracts. All of the parameters, with the exception of electrical conductivity, were elevated in at least some of the samples analyzed as part of this study. Specifically, soil pH was elevated (from 8.69 to 9.99) in five samples collected northeast and southwest of the C-152 pipeline leak. Similarly, samples collected from these same cone-pentrometer holes contained significantly more water-extractable sodium (more than 50 g/g of dry sediment), uranium (as much as 7.66E-01 g/g of dry sediment), nitrate (up to 30 g/g of dry sediment), and technetium-99 (up to 3.34 pCi/g of dry sediment). Most of the samples containing elevated concentrations of water-extractable sodium also had decreased levels of water extractable calcium and or magnesium, indicating that tank-related fluids that were high in sodium did seep into the vadose zone near these probe holes. Several of the samples containing high concentrations of water-leachable uranium also contained high pore water corrected alkalinity (3.26E+03 mg/L as CaCO3), indicating that the elevated water-leachable uranium could be an artifact of uranyl-carbonate complexation of naturally occurring labile uranium. However, a mass scan of the water extract containing the highest concentration of uranium was performed via inductively coupled mass spectrometry over the range of 230 to 240 atomic mass units, and a discernable peak was observed at mass 236. Although the data is considered qualitative, the presence of uranium-236 in the 1:1 sediment:water extract is a clear indication that the sample contains contaminant uranium [Hanford reprocessed fuel waste]. After evaluating all the characterization and analytical data, there is no question that the vadose zone surrounding the C-152 pipeline leak site has been contaminated by waste generally sent to tanks. The two zones or regions that contained the largest amount of contaminants, either in concentration or by occurrence of several key constituents/contaminants of concern, were located: 1) between the 241-C-151 and 241-C-152 Diversion Boxes (near the location of UPR-200-E-82) and 2) directly across the C-152 waste site near the C-153 Diversion Box (near where a pipeline, which connects the two diversion boxes, is shown on old blue prints . Without the use of more sophisticated analytical techniques, such as isotope signature analysis of ruthenium fission product isotopes, it is impossible to determine if the contamination observed at these two locations are from the same waste source or are a result of different leak events.« less
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