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Research about Idaho National Engineering and Environmental Laboratory

Source-linked reports with geographic coverage including Idaho National Engineering and Environmental Laboratory.

6 recordsLinked to original sources
USGS2005

Development of property-transfer models for estimating the hydraulic properties of deep sediments at the Idaho National Engineering and Environmental Laboratory, Idaho

Because characterizing the unsaturated hydraulic properties of sediments over large areas or depths is costly and time consuming, development of models that predict these properties from more easily measured bulk-physical properties is desirable. At the Idaho National Engineering and Environmental Laboratory, the unsaturated zone is composed of thick basalt flow sequences interbedded with thinner sedimentary layers. Determining the unsaturated hydraulic properties of sedimentary layers is one step in understanding water flow and solute transport processes through this complex unsaturated system. Multiple linear regression was used to construct simple property-transfer models for estimating the water-retention curve and saturated hydraulic conductivity of deep sediments at the Idaho National Engineering and Environmental Laboratory. The regression models were developed from 109 core sample subsets with laboratory measurements of hydraulic and bulk-physical properties. The core samples were collected at depths of 9 to 175 meters at two facilities within the southwestern portion of the Idaho National Engineering and Environmental Laboratory-the Radioactive Waste Management Complex, and the Vadose Zone Research Park southwest of the Idaho Nuclear Technology and Engineering Center. Four regression models were developed using bulk-physical property measurements (bulk density, particle density, and particle size) as the potential explanatory variables. Three representations of the particle-size distribution were compared: (1) textural-class percentages (gravel, sand, silt, and clay), (2) geometric statistics (mean and standard deviation), and (3) graphical statistics (median and uniformity coefficient). The four response variables, estimated from linear combinations of the bulk-physical properties, included saturated hydraulic conductivity and three parameters that define the water-retention curve. For each core sample,values of each water-retention parameter were estimated from the appropriate regression equation and used to calculate an estimated water-retention curve. The degree to which the estimated curve approximated the measured curve was quantified using a goodness-of-fit indicator, the root-mean-square error. Comparison of the root-mean-square-error distributions for each alternative particle-size model showed that the estimated water-retention curves were insensitive to the way the particle-size distribution was represented. Bulk density, the median particle diameter, and the uniformity coefficient were chosen as input parameters for the final models. The property-transfer models developed in this study allow easy determination of hydraulic properties without need for their direct measurement. Additionally, the models provide the basis for development of theoretical models that rely on physical relationships between the pore-size distribution and the bulk-physical properties of the media. With this adaptation, the property-transfer models should have greater application throughout the Idaho National Engineering and Environmental Laboratory and other geographic locations.

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USGS2003

Spatial variability of sedimentary interbed properties near the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory, Idaho

The subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL) is complex, comprised primarily of thick, fractured basalt flows interbedded with thinner sedimentary intervals. The unsaturated zone can be as thick as 200 m in the southwestern part of the INEEL. The Vadose Zone Research Park (VZRP), located approximately 10 km southwest of the Idaho Nuclear Technology and Engineering Center (INTEC), was established in 2001 to study the subsurface of a relatively undisturbed part of the INEEL. Waste percolation ponds for the INTEC were relocated to the VZRP due to concerns that perched water within the vadose zone under the original infiltration ponds (located immediately south of the INTEC) could contribute to migration of contaminants to the Snake River Plain aquifer. Knowledge of the spatial distribution of texture and hydraulic properties is important for developing a better understanding of subsurface flow processes within the interbeds, for example, by identifying low permeability layers that could lead to the formation of perched ground-water zones. Because particle-size distributions are easier to measure than hydraulic properties, particle size serves as an analog for determining how the unsaturated hydraulic properties vary both vertically within particular interbeds and laterally within the VZRP. As part of the characterization program for the subsurface at the VZRP, unsaturated and saturated hydraulic properties were measured on 10 core samples from six boreholes. Bulk properties, including particle size, bulk density, particle density, and specific surface area, were determined on material from the same depth intervals as the core samples, with an additional 66 particle- size distributions measured on bulk samples from the same boreholes. From lithologic logs of the 32 boreholes at the VZRP, three relatively thick interbeds (in places up to 10 m thick) were identified at depths of 35, 45, and 55 m below land surface. The 35-m interbed extends laterally over a distance of at least 900 m from the Big Lost River to the new percolation pond area of the VZRP. Most wells within the VZRP were drilled to depths less than 50 m, making it difficult to infer the lateral extent of the 45-m and 55-m interbeds. The 35-m interbed is uniform in texture both vertically and laterally; the 45-m interbed coarsens upward; and the 55-m interbed contains alternating coarse and fine layers. Seventy-one out of 90 samples were silt loams and 9 out of 90 samples were classified as either sandy loams, loamy sands, or sands. The coarsest samples were located within the 45-m and 55-m interbeds of borehole ICPP-SCI-V-215, located near the southeast corner of the new percolation pond area. At the tops of some interbeds, baked-zone intervals were identified by their oxidized color (yellowish red to red) compared to the color of the underlying non-baked material (pale yellow to brown). The average geometric mean particle diameter of baked-zone intervals was only slightly coarser, in some cases, than the underlying non-baked sediment. This is likely due to both depositional differences between the top and bottom of the interbeds and the presence of small basalt clasts in the sediment. Core sample hydraulic properties from baked zones within the different interbeds did not show effects from alteration caused during basalt deposition, but differed mainly by texture. Saturated hydraulic conductivities (Ksat) for the 10 core samples ranged from 10-7 to 10-4 cm/s. Low permeability layers, with Ksat values less than 10-7 cm/s, within the 35-m and 45-m interbeds may cause perched ground-water zones to form beneath the new percolation pond area, leading to the possible lateral movement of water away from the VZRP.

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USGS2003

Measurement of sedimentary interbed hydraulic properties and their hydrologic influence near the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory

Disposal of wastewater to unlined infiltration ponds near the Idaho Nuclear Technology and Engineering Center (INTEC), formerly known as the Idaho Chemical Processing Plant, at the Idaho National Engineering and Environmental Laboratory (INEEL) has resulted in the formation of perched water bodies in the unsaturated zone (Cecil and others, 1991). The unsaturated zone at INEEL comprises numerous basalt flows interbedded with thinner layers of coarse- to fine-grained sediments and perched ground-water zones exist at various depths associated with massive basalts, basalt-flow contacts, sedimentary interbeds, and sediment-basalt contacts. Perched ground water is believed to result from large infiltration events such as seasonal flow in the Big Lost River and wastewater discharge to infiltration ponds. Evidence from a large-scale tracer experiment conducted in 1999 near the Radioactive Waste Management Complex (RWMC), approximately 13 km from the INTEC, indicates that rapid lateral flow of perched water in the unsaturated zone may be an important factor in contaminant transport at the INEEL (Nimmo and others, 2002b). Because sedimentary interbeds, and possibly baked-zone alterations at sediment-basalt contacts (Cecil and other, 1991) play an important role in the generation of perched water it is important to assess the hydraulic properties of these units.

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USGS2002

Mercury deposition in snow near an industrial emission source in the western U.S. and comparison to ISC3 model predictions

Mercury (total and methyl) was evaluated in snow samples collected near a major mercury emission source on the Idaho National Engineering and Environmental Laboratory (INEEL) insoutheastern Idaho and 160 km downwind in Teton Range in westernWyoming. The sampling was done to assess near-field (<12 km)deposition rates around the source, compare them to those measured in a relatively remote, pristine downwind location, andto use the measurements to develop improved, site-specific modelinput parameters for precipitation scavenging coefficient and thefraction of Hg emissions deposited locally. Measured snow waterconcentrations (ng L -1 ) were converted to deposition (ugm -2 ) using the sample location snow water equivalent. Thedeposition was then compared to that predicted using the ISC3 airdispersion/deposition model which was run with a range ofparticle and vapor scavenging coefficient input values. Acceptedmodel statistical performance measures (fractional bias andnormalized mean square error) were calculated for the differentmodeling runs, and the best model performance was selected. Measured concentrations close to the source (average = 5.3 ngL -1 ) were about twice those measured in the Teton Range(average = 2.7 ng L -1 ) which were within the expected rangeof values for remote background areas. For most of the samplinglocations, the ISC3 model predicted within a factor of two of theobserved deposition. The best modeling performance was obtainedusing a scavenging coefficient value for 0.25 μm diameterparticulate and the assumption that all of the mercury isreactive Hg(II) and subject to local deposition. A 0.1 μm particle assumption provided conservative overprediction of thedata, while a vapor assumption resulted in highly variable predictions. Partitioning a fraction of the Hg emissions to elemental Hg(0) (a U.S. EPA default assumption for combustion facility risk assessments) would have underpredicted the observed fallout.

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USGS2000

Chemical and radiochemical constituents in water from wells in the vicinity of the naval reactors facility, Idaho National Engineering and Environmental Laboratory, Idaho, 1997-98

The U.S. Geological Survey, in response to a request from the U.S. Department of Energy?s Phtsburgh Naval Reactors Ofilce, Idaho Branch Office, sampled water from 13 wells during 1997?98 as part of a long-term project to monitor water quality of the Snake River Plain aquifer in the vicinity of the Naval Reactors Facility, Idaho National Engineering and Environmental Laboratory, Idaho. Water samples were analyzed for naturally occurring constituents and man-made contaminants. A totalof91 samples were collected from the 13 monitoring wells. The routine samples contained detectable concentrations of total cations and dissolved anions, and nitrite plus nitrate as nitrogen. Most of the samples also had detectable concentrations of gross alpha- and gross beta-particle radioactivity and tritium. Fourteen qualityassurance samples also were collected and analyze~ seven were field-blank samples, and seven were replicate samples. Most of the field blank samples contained less than detectable concentrations of target constituents; however, some blank samples did contain detectable concentrations of calcium, magnesium, barium, copper, manganese, nickel, zinc, nitrite plus nitrate, total organic halogens, tritium, and selected volatile organic compounds.

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