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At least 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Low diffusive methane emissions from the main channel of a large Amazonian run-of-the-river reservoir attributed to high methane oxidation

The global development of hydropower dams has rapidly expanded over the last several decades and has spread to historically non-impounded systems such as the Amazon River's main low land tributaries in Brazil. Despite the recognized significance of reservoirs to the global methane (CH4) emission, the processes controlling this emission remain poorly understood, especially in Tropical reservoirs. Here we evaluate CH4 dynamics in the main channel and downstream of the Santo Antônio hydroelectric reservoir, a large tropical run-of-the-river (ROR) reservoir in Amazonia. This study is intended to give a snapshot of the CH4 dynamics during the falling water season at the initial stage after the start of operations. Our results show substantial and higher CH4 production in reservoirs' littoral sediment than in the naturally flooded areas downstream of the dam. Despite the large production in the reservoir or naturally flooded areas, high CH4 oxidation in the main channel keep the concentration and fluxes of CH4 in the main channel low. Similar CH4 concentrations in the reservoir and downstream close to the dam suggest negligible degassing at the dam, but stable isotopic evidence indicates the presence of a less oxidized pool of CH4 after the dam. ROR reservoirs are designed to disturb the natural river flow dynamics less than traditional reservoirs. If enough mixing and oxygenation remain throughout the reservoir's water column, naturally high CH4 oxidation rates can also remain and limit the diffusive CH4 emissions from the main channel. Nevertheless, it is important to highlight that our results focused on emissions in the deep and oxygenated main channel. High emissions, mainly through ebullition, may occur in the vast and shallow areas represented by bays and tributaries. However, detailed assessments are still required to understand the impacts of this reservoir on the annual emissions of CH4.

Amazon, aquatic, biogeochemistry, carbon cycling, ↗
DOE OSTI2022

Quantification of Off-Channel Inundated Habitat for Pacific Chinook Salmon ( Oncorhynchus tshawytscha ) along the Sacramento River, California, Using Remote Sensing Imagery

Off-channel areas are one of the most impacted aquatic habitats by humans globally, as extensive agricultural and urban development has limited them to roughly 10% of historical extent. This is also true for California’s Sacramento River Valley, where historically frequent widespread inundation has been reduced to a few off-channel water bodies along the mid-Sacramento River. This remaining shallow-water habitat provides crucial ecological benefits to multiple avian and fish species, but especially to floodplain-adapted species such as Chinook salmon (Oncorhynchus tshawytscha). Characterizing spatiotemporal off-channel dynamics, including inundation extent and residence time, is fundamental to better understanding the intrinsic value of such habitats and their potential to support recovery actions. Remote sensing techniques have been increasingly used to map surface water at regional and local scales, with improved resolutions. As such, this study maps off-channel inundation areas and describes their temporal dynamics by analyzing pixel-based time- series of multiple water indices, modified Normalized Difference Water Index (mNDWI) and the Automated Water Extraction Index (AWEI), generated from LandSat-8 and Sentinel-2 data between 2013–2021. Quantified off-channel area was similar with each water index and method used, but improved performance was associated with Sentinel-2 products and AWEI index to identify wetted areas under lower mainstem discharges. Results indicate an uneven distribution of off-channel habitat in the study area, with limited inundated areas in upstream reaches (<16% of total off-channel area for greater flows). In addition, much less habitat exists for flows under 400 m 3 /s, an important migration cue for endangered winter-run Chinook salmon, limiting juvenile access to areas with enhanced rearing conditions. Off-channel habitat residence times averaged between 7 and 16 days, primarily defined by the rate of receding flows, with rapid flow recession providing marginal off-channel habitat. This study shows reasonable performance of moderate resolution LandSat-8 and Sentinel-2 remote sensing imagery to characterize shallow-water inundated habitat in higher-order rivers, and as a method to inform restoration and native fish recovery efforts.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Concurrent Changes in Extreme Hydroclimate Events in the Colorado River Basin

Extreme events resulting in catastrophic damage have more than doubled in the last five years, costing hundreds of lives and thousands of homes, and heavily undermining regional economic stability. At present, most of these hydroclimatic extreme events are documented by the media as individual events; however, in scientific terms, many are better understood as concurrent events—concurrent extremes of both temperature and precipitation (e.g., drought, floods). This paper considers concurrent changes in hydroclimate extremes, including heatwaves, drought, flooding, and low flows, in six historical-to-future (1970–1999, 2070–2099) Earth System Model (ESM) climate scenarios for the Colorado River basin. Results indicate that temperature-driven Impacts (heatwaves, drought) have the strongest responses while precipitation-driven Impacts have weaker responses. All Impacts exhibit an increase in magnitude from synoptic to annual time scales, with heatwaves increasing in strength about three times at the annual time scale versus the synoptic, while low flows only increase slightly. Critical watersheds in the Colorado were identified, highlighting the Blue River basin, Uncompahgre, East Taylor, Salt/Verde watersheds, locations of important water infrastructures, water resources, and hydrological research. Our results indicate that concurrent extreme hydroclimate events are projected to increase in the future and intensify within critical regions of the Colorado River basin. Considering extreme hydroclimate events concurrently is an important step towards linking economic and social effects of these events and their associated instabilities on a regional scale.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2023

Future Atmospheric Rivers and Impacts on Precipitation: Overview of the ARTMIP Tier2 High-Resolution Global Warming Experiment

Atmospheric rivers (ARs) are long, narrow synoptic scale weather features important for Earth’s hydrological cycle typically transporting water vapor poleward, delivering precipitation important for local climates. Understanding ARs in a warming climate is problematic because the AR response to climate change is tied to how the feature is defined. The Atmospheric River Tracking Method Intercomparison Project (ARTMIP) provides insights into this problem by comparing 16 atmospheric river detection tools (ARDTs) to a common dataset consisting of high resolution climate change simulations from a global atmospheric general circulation model. ARDTs mostly show increases in frequency and intensity, but the scale of the response is largely dependent on algorithmic criteria. Across ARDTs, bulk characteristics suggest intensity and spatial footprint are inversely correlated, and most focus regions experience increases in precipitation volume coming from extreme ARs. The spread of the AR precipitation response under climate change is large and dependent on ARDT selection.

Atmospheric Rivers↗
NASA NTRS2024

Multitemporal landslide inventory and susceptibility map for the Arun River Basin, Nepal

The transboundary Arun River Basin (ARB) spreads across Nepal and Tibet. Nearly 95% of the basin lies in Tibet through which the Pumqu River flows, forming the Arun River once it enters Nepal. The ARB has five large hydropower projects undergoing construction or planned for the future. Rainfall and earthquake-induced landslides, landslide dammed lakes and landslide-induced glacial lake outburst floods pose major risks to smooth operation of these projects. To safeguard upcoming hydropower projects, areas susceptible to landslides in the ARB must be identified. We used high-resolution satellite imagery and open-source tools to generate a multitemporal landslide inventory for the basin. The rigorously quality-controlled inventory represents a yearly record of landslides from 2011 to 2020. A data-driven approach was used to map areas susceptible to landslides within the ARB. The multitemporal landslide inventory combined with other readily available Earth observation-based variables were used to create a landslide susceptibility map. The susceptibility analysis provides a valuable initial estimate of where landslides are likely to initiate. These landslide products could form the basis of more comprehensive local studies to inform hydropower project development.

Arun River Basin↗
NASA NTRSDate not supplied

The Global Water Monitor: Lake, Wetland, and River Reach Monitoring for Resource Management and Hazard Observation

The Global Water Monitor is a monitoring program offering surface water-related products for lakes, reservoirs, river reaches, and wetlands, https://blueice.gsfc.nasa.gov/gwm. These products are derived from multiple satellite-based altimetry and multispectral imaging platforms. The primary measurements are water level, slope, and extent, derived from a series of NASA and other agency instruments (Sentinel-3,-6, ICESat-2, SWOT, MODIS). The system serves stakeholders, the US Department of Agriculture Foreign Agricultural Service and the US Geological Survey, as well as various international, national, state, and intelligence agencies, engineers, ecologists, and hydrological researchers. Considering the sensitivity of ground-based data and the remote accessibility of many basins, the satellites offer global coverage, accuracy, and continuity of measurements. Observation of storage fluctuations in lakes and reservoirs provides users with knowledge of short and long-term drought conditions that can affect both water and energy resources. Emphasis is on changing climatic conditions, water sharing between nations, and regional stability. Measurements across a wetland complex can assist with efforts to assess hydrological dynamics with a focus on conservation efforts that aid both natural ecology and the sharing of precious water resources – the latter potentially being required in a basin across the municipal, crop irrigation, aquaculture, livestock, and power station spectrum. Observations of river reaches assists in the collection of basic hydraulic information, particularly in gauge-poor regions, for modelling efforts and the estimation of discharge, and at high-latitudes satellite-based river observations serve projects that warn of spring melts and flood hazards. We look at how recent improvements in instrument technology and mission operations are assisting with acquiring true global coverage and cross-validation efforts, and how stakeholders interact with the project in terms of setting requirements, product format, and accessibility methods. Examples show the application of the products across a range of programs, and in addition to meeting operational requirements, how the multi-decadal surface water levels are creating a high-quality timeline of Earth Data Records.

Lakes↗
DOE OSTI2013

UNCERTAINTY ANALYSIS FOR THE TECHA RIVER DOSIMETRY SYSTEM

Uncertainties in the doses estimated for the members of the Techa River Cohort (TRC) are being estimated with a two-dimensional Monte Carlo approach. In order to provide more accurate and precise estimates of individual dose (and thus more precise estimates of radiation risk) for the members of the TRC, a new dosimetric calculation system, the Techa River Dosimetry System-2009 (TRDS-2009) has been prepared. The deterministic version of the improved dosimetry system TRDS-2009D was basically completed in April 2009. Recent developments in evaluation of dose-response models in light of uncertain dose have highlighted the importance of different types of uncertainties in the development of individual dose estimates. These include uncertain parameters that may be either shared (common to some or all individuals) or unshared (a unique value for each person whose dose is to be estimated) within the dosimetric cohort. The nature of the type of uncertainty may be aleatory (random variability of true values due to stochastic processes) or epistemic (due to lack of complete knowledge about a unique quantity). Finally, there is a need to identify whether the structure of the errors is either related to measurement (the estimate differs from the true value by an error that is stochastically independent of the true value; frequently called classical uncertainty) or related to grouping (the true value varies from the estimate by an error that is random and is independent of the estimate; frequently called Berkson uncertainty). An approach has been developed that identifies the nature of the various input parameters and calculational methods incorporated in the Techa River Dosimetry System (based on the TRDS-2009D implementation), and a stochastic calculation model has been prepared to estimate the uncertainties in the dose estimates. This article reviews the concepts of uncertainty analysis, the equations, and input parameters, and then identifies the authors’ interpretations of their general nature. It presents the approach selected so that the stochastic, Monte-Carlo, implementation of the dosimetry system - TRDS-2009MC - provides useful information regarding the uncertainties of the doses.

uncertainty analysis, radiation dosimetry, Techa R↗
DOE OSTI2013

Enhanced Geothermal System Potential for Sites on the Eastern Snake River Plain, Idaho

The Snake River volcanic province overlies a thermal anomaly that extends deep into the mantle and represents one of the highest heat flow provinces in North America (Blackwell and Richards, 2004). This makes the Snake River Plain (SRP) one of the most under-developed and potentially highest producing geothermal districts in the United States. Elevated heat flow is typically highest along the margins of the topographic SRP and lowest along the axis of the plain, where thermal gradients are suppressed by the Snake River aquifer. Beneath this aquifer, however, thermal gradients rise again and may tap even higher heat flows associated with the intrusion of mafic magmas into the mid-crustal sill complex (e.g., Blackwell, 1989).

15 GEOTHERMAL ENERGY↗
DOE OSTI2016

Mighty Microbes Where Rivers Run

Microbes and their influential role in Earth’s climate take center stage in the area where river water and groundwater mix – an area known as the hyporheic zone. PNNL ecologist James Stegen discusses his team’s research in his “laboratory” – the zone along the Columbia, one of the nation’s largest rivers. It’s a squishy, porous lab, better known for soaking feet than serving as the “river’s liver.”

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Decommissioning an Active Historical Reactor Facility at the Savannah River Site - 13453

The Savannah River Site (SRS) is an 802 square-kilometer United States Department of Energy (US DOE) nuclear facility located along the Savannah River near Aiken, South Carolina, where Management and Operations are performed by Savannah River Nuclear Solutions (SRNS). In 2004, DOE recognized SRS as structure within the Cold War Historic District of national, state and local significance composed of the first generation of facilities constructed and operated from 1950 through 1989 to produce plutonium and tritium for our nation's defense. DOE agreed to manage the SRS 105-C Reactor Facility as a potentially historic property due to its significance in supporting the U.S. Cold War Mission and for potential for future interpretation. This reactor has five primary areas within it, including a Disassembly Basin (DB) that received irradiated materials from the reactor, cooled them and prepared the components for loading and transport to a Separation Canyon for processing. The 6,317 square meter area was divided into numerous work/storage areas. The walls between the individual basin compartments have narrow vertical openings called 'slots' that permit the transfer of material from one section to another. Data indicated there was over 830 curies of radioactivity associated with the basin sediments and approximately 9.1 M liters of contaminated water, not including a large quantity of activated reactor equipment, scrap metal, and debris on the basin floor. The need for an action was identified in 2010 to reduce risks to personnel in the facility and to eliminate the possible release of contaminants into the environment. The release of DB water could potentially migrate to the aquifer and contaminate groundwater. DOE, its regulators [U. S. Environmental Protection Agency (USEPA)-Region 4 and the South Carolina Department of Health and Environmental Control (SCDHEC)] and the SC Historical Preservation Office (SHPO) agreed/concurred to perform a non-time critical removal action for the In Situ Decommissioning (ISD) of the 105-C Disassembly Basin. ISD consisted of stabilization/isolation of remaining contaminated water, sediment, activated reactor equipment, and scrap metal by filling the DB with underwater non-structural grout to the appropriate (-4.877 meter) grade-level, thence with dry area non-structural grout to the final -10 centimeter level. The roof over the DB was preserved due to its potential historical significance and to prevent the infiltration of precipitation. Forced evaporation was the form of treatment implemented to remove the approximately 9.1 M liters of contaminated basin water. Using specially formulated grouts, irradiated materials and sediment were treated by solidification/isolation thus reducing their mobility, reducing radiation exposure and creating an engineered barrier thereby preventing access to the contaminants. Grouting provided a low permeability barrier to minimize any potential transport of contaminants to the aquifer. Efforts were made to preserve the historical significance of the Reactor in accordance with the National Historic Preservation Act. ISD provides a cost effective means to isolate and contain residual radioactivity from past nuclear operations allowing natural radioactive decay to reduce hazards to manageable levels. This method limits release of radiological contamination to the environment, minimizes radiation exposure to workers, prevents human/animal access to the hazardous substances, and allows for ongoing monitoring of the decommissioned facility. Field construction was initiated in August 2011; evaporator operations commenced January 2012 and ended July 2012 with over 9 M liters of water treated/removed. Over 8,525 cubic meters of grout were placed, completing in August 2012. The project completed with an excellent safety record, on schedule and under budget. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Integration of Environmental Compliance at the Savannah River Site - 13024

The Savannah River Site (SRS) is a large federal installation hosting diverse missions and multiple organizations with competing regulatory needs. Accordingly, there was a need to integrate environmental compliance strategies to ensure the consistent flow of information between Department of Energy-Savannah River (DOE-SR), the regulatory agencies and other interested parties. In order to meet this objective, DOE and major SRS contractors and tenants have committed to a strategy of collaboratively working together to ensure that a consistent, integrated, and fully coordinated approach to environmental compliance and regulator relationships is maintained. DOE-SR and Savannah River Nuclear Solutions, LLC, the SRS management and operations contractor, have established an environmental compliance integration process that provides for the consistent flow down of requirements to projects, facilities, SRS contractors, and subcontractors as well as the upward flow of information to assist in the early identification and resolution of environmental regulatory issues and enhancement of compliance opportunities. In addition, this process strongly fosters teamwork to collaboratively resolve complex regulatory challenges, promote pollution prevention and waste minimization opportunities to advance site missions in a manner that balances near-term actions with the long-term site vision, while being protective of human health and the environment. Communication tools are being utilized, some with enhancements, to ensure appropriate information is communicated to all levels with environmental responsibility at SRS. SRS internal regulatory integration is accomplished through a variety of informational exchange forums (e.g., Challenges, Opportunities and Resolution (COR) Team, DOE's Joint Site Regulatory Integration Team, and the Senior Environmental Managers Council (SEMC)). SRS communications and problem-solving with the regulatory agencies have been enhanced through formation of an interagency 'SRS Regulatory Integration Team (SRIT)'. The SRIT is a partnership comprised of representatives from DOE-SR (with contractor support), EPA Region 4 and the South Carolina Department of Health and Environmental Control (SCDHEC) and is chartered to develop a consensus understanding of SRS regulatory issues and activities. These forums and a formal environmental compliance integration process improve timely cross-functional decision making, problem solving, information sharing, and issue resolution. The SRS internal process has been formally documented in an Environmental Regulatory Integration Program Description, which is linked to the SRS Environmental Policy and agreed upon by all major contractors, subcontractors and tenants. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Savannah River Site Footprint Reduction Results under the American Recovery and Reinvestment Act - 13302

The Savannah River Site (SRS) is an 802 square-kilometer United States Department of Energy (US DOE) nuclear facility located along the Savannah River near Aiken, South Carolina, managed and operated by Savannah River Nuclear Solutions. Construction of SRS began in the early 1950's to enhance the nation's nuclear weapons capability. Nuclear weapons material production began in the early 1950's, eventually utilizing five production reactors constructed to support the national defense mission. Past operations have resulted in releases of hazardous constituents and substances to soil and groundwater, resulting in 515 waste sites with contamination exceeding regulatory thresholds. More than 1,000 facilities were constructed onsite with approximately 300 of them considered radiological, nuclear or industrial in nature. In 2003, SRS entered into a Memorandum of Agreement with its regulators to accelerate the cleanup using an Area Completion strategy. The strategy was designed to focus cleanup efforts on the 14 large industrial areas of the site to realize efficiencies of scale in the characterization, assessment, and remediation activities. This strategy focuses on addressing the contaminated surface units and the vadose zone and addressing groundwater plumes subsequently. This approach streamlines characterization and remediation efforts as well as the required regulatory documentation, while enhancing the ability to make large-scale cleanup decisions. In February 2009, Congress approved the American Reinvestment and Recovery Act (ARRA) to create jobs and promote economic recovery. At SRS, ARRA funding was established in part to accelerate the completion of environmental remediation and facility deactivation and decommissioning (D and D). By late 2012, SRS achieved 85 percent footprint reduction utilizing ARRA funding by accelerating and coupling waste unit remediation with D and D of remnant facilities. Facility D and D activities were sequenced and permitted with waste unit remediation activities to streamline regulatory approval and execution. Achieving footprint reduction fulfills the Government's responsibility to address legacy contamination; allows earlier completion of legally enforceable compliance agreement milestones; and enables future potential reuse of DOE resources, including land and infrastructure for other missions. Over the last 3.5 years significant achievements were met that contributed to footprint reduction, including the closure of 41 waste units (including 20 miles of radiologically contaminated stream) and decommissioning of 30 facilities (including the precedent setting in situ closure of two former production reactors, the first in the DOE Complex). Other notable achievements included the removal of over 39,750 cubic meters of debris and 68,810 cubic meters of contaminated soils, including 9175 cubic meters of lead-contaminated soil from a former site small arms testing range and treatment of 1,262 cubic meters of tritium-laden soils and concrete using a thermal treatment system. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Facility Utilization and Risk Analysis for Remediation of Legacy Transuranic Waste at the Savannah River Site - 13572

Savannah River Nuclear Solutions (SRNS) completed the Accelerated TRU Project for remediating legacy waste at the Savannah River Site with significant cost and schedule efficiencies due to early identification of resources and utilization of risk matrices. Initial project planning included identification of existing facilities that could be modified to meet the technical requirements needed for repackaging and remediating the waste. The project schedule was then optimized by utilization of risk matrices that identified alternate strategies and parallel processing paths which drove the overall success of the project. Early completion of the Accelerated TRU Project allowed SRNS to pursue stretch goals associated with remediating very difficult TRU waste such as concrete casks from the hot cells in the Savannah River National Laboratory. Project planning for stretch goals also utilized existing facilities and the risk matrices. The Accelerated TRU project and stretch goals were funded under the American Recovery and Reinvestment Act (ARRA). (authors)

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

25 years of environmental remediation in the general separations area of the Savannah river site: lessons learned about what worked and what did not work in soil and groundwater cleanup - 15270

The Savannah River Site, which is owned and administered by the US Department of Energy, covers approximately 900 square kilometers. The General Separation Area is located in the center of the site and includes: radioactive material chemical separations facilities, radioactive waste tank farms, radioactive seepage basins, and the radioactive waste burial grounds. Radioactive wastes were disposed in the General Separation Area from the mid-1950's through the mid-1990's. Operations at the F Canyon began in 1954 and at H Canyon began in 1955. Waste water disposition to the F and H Seepage Basins began soon after operations started in the canyons. The Old Radioactive Waste Burial Ground began operations in 1952 to manage solid waste that could be radioactive from all the site operations, and ceased receiving waste in 1972. The Mixed Waste Management Facility and Low Level Radioactive Waste Disposal Facility received radioactive solid waste from 1969 until 1995. Environmental legislation enacted in the 1970's through 1990's led to changes in waste management and environmental cleanup practices. The US Congress passed the Clean Air Act in 1970 and the Clean Water Act in 1972; the Resource Conservation and Recovery Act was enacted in 1976; the Comprehensive Environmental Response Compensation, and Liability Act was enacted by Congress in 1980; and the Federal Facilities Compliance Act was signed into law in 1992. Environmental remediation at the Savannah River Site essentially began with a 1987 Settlement Agreement between the Savannah River Site and the State of South Carolina. The site manages several of the larger groundwater remedial activities under the Resource Conservation and Recovery Act for facilities recognized early on as environmental problems. All subsequent remediation projects are managed under a tri-party agreement (Department of Energy, Environmental Protection Agency, and South Carolina Department of Health and Environmental Control) through the Federal Facilities Agreement. Environmental remediation activities during the past 25 years have stabilized and capped seepage basins as well as consolidated and capped waste units and burial grounds in the General Separation Area. Groundwater activities include: pump and treat systems in the groundwater, installation of deep subsurface barrier systems to manage groundwater flow, in situ chemical treatments in the groundwater, and captured contaminated groundwater discharges at the surface for management in a forest irrigation system. Concentrations of contaminants in the aquifers beneath the General Separation Area and in surface water streams in the General Separation Area have decreased over the past 25 years. Closure of 65 waste sites and 4 Resource Conservation and Recovery Act facilities has been successfully accomplished. Environmental clean-up has progressed to the stage where most of the work involves monitoring, optimization, and maintenance of existing remedial systems. Many lessons have been learned in the process of remediating the General Separations Area. Geo-textile covers outperform low permeability clay caps, especially with respect to the amount of repairs required to upkeep the drainage layers as the caps age. Passive and enhanced natural processes to address contamination are much more cost effective than pump and treat systems. Forest irrigation can be very effective in water management situations with non-accumulative contaminants such as tritium and volatile organic contaminants. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Sodium silicate treatment for uranium (vi) bearing groundwater systems at f/h area at savannah river site - 15709

The Savannah River Site (SRS) was one of the most significant manufacturing facilities during the Cold War era for producing nuclear materials. At the end of the Cold War, the Site's mission changed to support the environmental restoration of the Site due to over six decades of research, development, and production of nuclear weapons. Currently SRS is a major hazardous waste management facility responsible for nuclear materials storage, and remediation of contaminated soil and groundwater from radionuclides. This research focuses on controlling the mobilization of the contaminants, specifically uranium (VI) located in groundwater plumes at the Site's F/H Area Seepage Basin, where approximately 1.8 billion gallons of hazardous waste were deposited. Objective: To evaluate the potential use of sodium silicate for uranium removal from the aqueous phase, as well as to restore the pH of the treatment zone. Adding sodium silicate increases the pH of the treatment zone and uranium precipitation is achieved, therefore immobilizing the contaminant. Through a series of experiments the optimal concentration of sodium silicate was investigated. Part 1: An experiment was conducted in order to determine the effect of sodium silicate on the pH of a solution containing Savannah River Site soil and synthetic groundwater replicated after the Site's natural groundwater composition. Each sample was spiked with the appropriate volume from the sodium silicate stock solution in order to achieve final desired sodium silicate concentrations of 10, 20, 40,50,60,70, and 80 parts per million. The samples were placed on a platform shaker for three days during which pH readings were collected in regular intervals to determine which silicate concentration produced a pH in the neutral range (6 > pH < 8). Part 2: A sequential experiment was conducted specifically using 40 and 50 ppm of sodium silicate with Savannah River Site soil, synthetic groundwater, and 0.5 ppm of uranium (VI), in order to investigate the removal of uranium in the aqueous phase via precipitation. Samples were extracted and categorized into a filtered and non-filtered control group. Each sample was diluted 1:20 with 1% nitric acid and analyzed using the Kinetic Phosphorescence Analyzer (KPA) in order to measure uranium concentrations in the supernatant. By measuring the concentration of uranium in the supernatant the percent removal is obtained for the comparison between the filtered and non-filtered samples, revealing the amount of uranium precipitation that occurred for each silicate concentration. Results: A sodium silicate concentration of between 40-50 ppm proved ideal for achieving uranium precipitation and creating a circum-neutral pH environment in the aqueous phase. 50 ppm achieved the larger percent of uranium precipitation with a range of 30-50% removal for the filtered samples and between 60-95% removal for the non-filtered samples. A large difference between the removal of filtered and non- filtered samples from the same day was observed for both sodium silicate concentrations tested, indicating that there is a considerable amount of uranium species retained in the filter. The addition of sodium silicate proved effective in the removal of uranium precipitation from the aqueous phase. Future work: Determine potential re-solubilization of uranium concentrations; Examine mineralogy and surface morphology of dried precipitate using XRD and SEM/EDS.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Motivation of Public Participation at Citizens Advisory Board Meetings Public Participation at the Savannah River Site Citizen Advisory Board Meetings - 16343

The objective of this paper is to interview public participants who attended both full-board and committee meetings for a pre-determined two-month period to understand their motivation in attending Savannah River Site Citizens Advisory Board (SRS CAB) meetings. In addition, the research aimed to learn what impact they believe their attendance had on Savannah River Site Citizens Advisory Board (SRS CAB) recommendations and discussion, as well as how their input is utilized by the Savannah River Site. Perhaps in learning these community members attend meetings, the CAB can capitalize on that knowledge to motivate additional public participation. Research for this report includes a literature review of public participation and analysis of interviews and surveys conducted with members of the general public in October and November 2015. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Prioritizing and Managing Technology Needs to Meet River Protection Project Mission Objectives - 16462

Over 56 million gallons of radioactive waste are stored in 177 large underground tanks at the Hanford Site, located in southeastern Washington State. This nuclear waste resulted from plutonium production for the nation's nuclear defense program. The River Protection Project (RPP) mission is to: - Safeguard and safely manage waste stored in the Hanford tanks, - Treat the waste using the Waste Treatment and Immobilization Plant (WTP), - Ensure safe disposition of the waste to protect the Columbia River and the environment. Each aspect of the mission requires some application of technology in order to meet the mission objectives. The RPP Technology Roadmap document presents a comprehensive, integrated assessment of the technology-related advances needed to ensure successful completion of the Hanford tank waste cleanup mission. This paper describes the development of the RPP Technology Roadmap, summarizes its content, describes integration and collaboration with the Department of Energy's national laboratories to support the work identified, and defines how priorities were identified to ensure near-term RPP mission commitments can be accomplished while preserving the longer term technology development elements necessary for mission completion. The Challenge - Managing a wide variety of technology needs that involve multiple organizations, contractors, and national laboratories presents additional challenges when funding constraints are factored in. A process was needed to ensure the technology needs supporting near term mission priorities were appropriately identified, prioritized, and supported through the fiscal year planning process. Additionally, the national laboratory resources necessary to support many of the technologies require coordination to ensure the most appropriate resources are applied at the appropriate level without duplication or contradiction of effort. The Solution - The RPP Technology Roadmap was developed with the primary purposes to: - Identify technology related items needed to support or enhance the River Protection Project (RPP) mission, - Prioritize technology needs to support fiscal year planning processes, - Organize National laboratory support of the RPP mission and communicate needs to the participating contractors. The Technology Roadmap is consistent with Department of Energy (DOE) Hanford mission priorities and is also in alignment with other Hanford Site technical initiatives and policy and planning documents. The Technology Roadmap highlights the current estimated technology needs and identifies where planning shortfalls exist and where national laboratory participation is needed to support mission success. This information assists fiscal year planning and national laboratory contracting processes to ensure that technology needs are supported. In addition to supporting the RPP baseline mission, the Technology Roadmap provides a basis for strategic planning by identifying opportunities to use technology solutions to enhance mission efficiency. This waste management paper describes the innovative and collaborative processes used to develop, validate, and communicate the results so the project owners and the national laboratories can most effectively plan work scope and resources. A discussion of the following processes is included: - Technology needs and task owner identification, - Functional area grouping and area lead identification, - Needs prioritization, - High priority needs ranking (including validation), - Results compilation and planning gap identification, - Results presentation by project and functional area, - National laboratory coordination and collaboration. Application - The process used to develop the RPP technology roadmap is applicable to any site where multiple national laboratories and contractors are involved in identifying and implementing technology based solutions. This process is also applicable to the DOE HQ role to provide prioritization and coordination of the nationwide technology development activities. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Cs-137 Body-burdens in Wild Pigs on the Department of Energy's Savannah River Site: Determination of an Appropriate Framework for Spatiotemporal Analysis of Hunter Dose Tracking System Data

The Savannah River Site (SRS) is a U.S. Department of Energy facility with an area of 310 square miles. Since its opening in 1951, SRS has produced and processed nuclear materials for national defense and industrial purposes. These activities have resulted in the release of radiocesium (Cs-137) which has led to contamination of associated streams, floodplains, man-made reservoirs, soil and vegetation. Contamination is spread to wild pigs as they move about SRS, consume vegetation, drink water and wallow in soil. SRS provides annual deer hunts open to the public in which wild pigs may be taken as well. The Cs-137 concentration of each animal is determined before it is released to the hunter for consumption and a cumulative dose is retained for each individual hunter. These tasks are accomplished using the Hunter Dose Tracking System (HDTS). The data collected on SRS by the HDTS for White-Tailed deer has been extensively analyzed. A repeatable method for calculating the background radiocesium body burden for the SRS deer population was established by Gaines and Novak (2009,2016). This model was framed using Cs-137 contamination obtained via gamma over-flight data, the decay rate of radiocesium and the historical behavior observed in the SRS deer population. These parameters were used in a spatiotemporal analysis to estimate background Cs-137 body burdens (from global fallout, etc.), as well as the effect SRS activities may have. The purpose of this project is to modify the framework to represent the behavior of the wild pig population on SRS such that HDTS data collected may be analyzed similarly. The 2018 data were collected via the HDTS in the field to screen wild pigs dispatched by Forest Service - Savannah River. These data will provide insight for an analysis of seasonal variance in the body burdens of the SRS wild pig population. The HDTS quickly provided Cs-137 concentrations in the field, as well as automatically updated the electronic database. Space: Historically, the average home range of wild pigs on the Savannah River Site has been reported at approximately six square miles. This range was confirmed accurate as of July 2018, with the observed minimum and maximum at one and ten square miles respectively. This range was geoprocessed using ArcMap to project buffers based on 1991 gamma over-flight data. The buffers were constructed to originate at all Cs-137 contamination point coordinates and protrude outward in all directions for 1.5, 2.45 and 6 square miles. While the 2.45 mile buffer is theoretically representative of potential hog exposure based on the average home range, it does not consider the possibility of home ranges not uniform in shape. Therefore, the 1.5 and 6 mile buffers were also constructed as visual aids for determining the appropriate hunt compartments for background level considerations. The SRS is divided into numbered hunt compartments of varying size and shape. These compartment numbers are used during sponsored hunts to record the location in which a wild pig was dispatched. Time: The Gaines report determined deer analysis should be carried out at the half-decade level for the best representation of true body burdens. This is due to the impact natural factors, such as drought or flood, can have on the bioaccumulation of Cs-137. To determine the appropriate time scale for hog analysis, all available data was totaled and averaged at 1, 2, 3 and 7 year increments. The annual averages and running average are provided. The appropriate compartments for the determination of the SRS hog population background level should be: 2, 3, 4, 9, 10, 14 and 15. Hogs dispatched within other compartments are most likely exposed to Cs-137 contamination and should not be included in the background level. The current dataset is small, but was still able to demonstrate the relationship between where hogs on SRS and the Cs-137 body burdens they incur. Geoprocessing the data using the average home range of wild pigs highlighted the importance of collecting additional samples from areas surrounding SRS if an accurate background is to be determined. When the average concentration of Cs-137 in pigs from background compartments is compared against that of pigs from contaminated compartments, a significant difference can be seen. A Table provides a summary of the analyzed data from the 15 years processed thus far.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗