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All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Reducing Contingency through Sampling at the Luckey FUSRAP Site - 13186

Typically, the greatest risk in developing accurate cost estimates for the remediation of hazardous, toxic, and radioactive waste sites is the uncertainty in the estimated volume of contaminated media requiring remediation. Efforts to address this risk in the remediation cost estimate can result in large cost contingencies that are often considered unacceptable when budgeting for site cleanups. Such was the case for the Luckey Formerly Utilized Sites Remedial Action Program (FUSRAP) site near Luckey, Ohio, which had significant uncertainty surrounding the estimated volume of site soils contaminated with radium, uranium, thorium, beryllium, and lead. Funding provided by the American Recovery and Reinvestment Act (ARRA) allowed the U.S. Army Corps of Engineers (USACE) to conduct additional environmental sampling and analysis at the Luckey Site between November 2009 and April 2010, with the objective to further delineate the horizontal and vertical extent of contaminated soils in order to reduce the uncertainty in the soil volume estimate. Investigative work included radiological, geophysical, and topographic field surveys, subsurface borings, and soil sampling. Results from the investigative sampling were used in conjunction with Argonne National Laboratory's Bayesian Approaches for Adaptive Spatial Sampling (BAASS) software to update the contaminated soil volume estimate for the site. This updated volume estimate was then used to update the project cost-to-complete estimate using the USACE Cost and Schedule Risk Analysis process, which develops cost contingencies based on project risks. An investment of $1.1 M of ARRA funds for additional investigative work resulted in a reduction of 135,000 in-situ cubic meters (177,000 in-situ cubic yards) in the estimated base volume estimate. This refinement of the estimated soil volume resulted in a $64.3 M reduction in the estimated project cost-to-complete, through a reduction in the uncertainty in the contaminated soil volume estimate and the associated contingency costs. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Geochemical Evaluation of Uranium Fate and Transport Guterl Specialty Steel Site, New York - 12077

Between 1948 and 1952, up to 15,875 metric tons (35 million pounds) of natural uranium metal (U) were processed at the former Guterl Specialty Steel Corporation site in Lockport, New York. The resulting dust, thermal scale, mill shavings and associated land disposal contaminated both the facility and on-site soils. Uranium subsequently impacted groundwater and a fully developed plume exists below the site. Site soils are composed of anthropogenic fill and re-worked, glacially-derived native soil. This overburden is underlain by the weathered and fractured Lockport Dolostone bedrock. Shallow groundwater levels fluctuate seasonally and allow groundwater to contact U contaminated soil, which promotes transport. This condition is exemplified through coincident increases in specific conductivity and groundwater levels, which flush soluble constituents in the fill/soil to groundwater during recharge events. In addition, water-level fluctuations affect reduction-oxidation (redox) conditions at the site. The U in soils is subject to wetting and drying cycles that promote oxidation more than stable redox conditions (e.g., dry soil or fully saturated conditions). This oxidizing mechanism increases uranium solubility and mobility. Site groundwater also receives uranium via leaching from near-surface contaminated fill. The strong correlation between nitrate and uranium in groundwater indicates that uranium is mobile where oxidizing conditions occur. Analytical models of contaminant leaching determined that multiple pathways and transport mechanisms govern site risk. Uranium transport to groundwater involves three mechanisms: 1) direct contact of contaminated soil with groundwater, 2) the oxidation-state or chemical valence of uranium, and 3) the leaching of near-surface contamination to groundwater. These mechanisms require an integrated remedial solution that is sustainable and cost effective. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

Site-Specific Analyses for Demonstrating Compliance with 10 CFR 61 Performance Objectives - 12179

The U.S. Nuclear Regulatory Commission (NRC) is proposing to amend its regulations at 10 CFR Part 61 to require low-level radioactive waste disposal facilities to conduct site-specific analyses to demonstrate compliance with the performance objectives in Subpart C. The amendments would require licensees to conduct site-specific analyses for protection of the public and inadvertent intruders as well as analyses for long-lived waste. The amendments would ensure protection of public health and safety, while providing flexibility to demonstrate compliance with the performance objectives, for current and potential future waste streams. NRC staff intends to submit proposed rule language and associated regulatory basis to the Commission for its approval in early 2012. The NRC staff also intends to develop associated guidance to accompany any proposed amendments. The guidance is intended to supplement existing low-level radioactive waste guidance on issues pertinent to conducting site-specific analyses to demonstrate compliance with the performance objectives. The guidance will facilitate implementation of the proposed amendments by licensees and assist competent regulatory authorities in reviewing the site-specific analyses. Specifically, the guidance provides staff recommendations on general considerations for the site-specific analyses, modeling issues for assessments to demonstrate compliance with the performance objectives including the performance assessment, intruder assessment, stability assessment, and analyses for long-lived waste. This paper describes the technical basis for changes to the rule language and the proposed guidance associated with implementation of the rule language. The NRC staff, per Commission direction, intends to propose amendments to 10 CFR Part 61 to require licensees to conduct site-specific analyses to demonstrate compliance with performance objectives for the protection of public health and the environment. The amendments would require a performance assessment to demonstrate protection of the general population from releases of radioactivity, an assessment to demonstrate protection of a potential inadvertent intruder, and a long-term analysis to assess how the design of the facility considers the potential radiological impacts associated with disposal of long-lived waste streams. Concurrently, the NRC staff intends to propose associated guidance to facilitate the implementation of the requirements to conduct site-specific analyses. In proposing these amendments to the regulation and associated guidance, the NRC staff has conducted extensive public outreach since 2009 including three public meetings and four briefings of the NRC's Advisory Committee on Reactor Safeguards. The NRC staff plans to submit the proposed amendments to the regulations to the Commission in early 2012. Subsequently, the proposed amendments and associated guidance would be published in the Federal Register for public comment pending approval of the proposed amendments to the regulations by the Commission. Following the public comment period, NRC staff plans to address public comments and revise, as necessary, the regulations and associated guidance before publishing a final rule, which is anticipated in 2013. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Solar-Powered Air Stripping at the Rocky Flats Site, Colorado - 12361

The U.S. Department of Energy's Rocky Flats Site (the Site), near Denver, Colorado, is a former nuclear weapons facility that was constructed beginning in 1951. With the end of the Cold War, the Site was cleaned up and closed in 2005. Four gravity-driven groundwater treatment systems were installed during cleanup, and their continued operation was incorporated into the final remedy for the Site. All utilities, including electrical power, were removed as part of this closure, so all Site electrical power needs are now met with small solar-powered systems. The Mound Site Plume Treatment System (MSPTS) was installed in 1998 as an innovative system based on zero-valent iron (ZVI). Groundwater flow from the Mound source area containing elevated concentrations of volatile organic compounds (VOCs), primarily in the tetrachloroethene (PCE)-trichloroethene (TCE) family of chlorinated solvents, is intercepted by a collection trench and routed to twin ZVI treatment cells. Later, in 2005, remediation of VOC-contaminated soils at a second up-gradient source area included adding an electron donor to the backfill to help stimulate biodegradation. This reduced concentrations of primary constituents but caused down-gradient groundwater to contain elevated levels of recalcitrant degradation byproducts, particularly cis-1,2-dichloroethene and vinyl chloride. A gravel drain installed as part of the 2005 remediation directs contaminated groundwater from this second source area to the MSPTS for treatment. This additional contaminant load, coupled with correspondingly reduced residence time within the ZVI media due to the increased flow rate, resulted in reduced treatment effectiveness. Elevated concentrations of VOCs were then detected in MSPTS effluent, as well as in surface water at the downstream performance monitoring location for the MSPTS. Subsequent consultations with the Site regulators led to the decision to add a polishing component to reduce residual VOCs in MSPTS effluent. Initially, several alternatives such as commercial air strippers and cascade aerators were evaluated; resulting cost estimates exceeded $100,000. After several simpler alternatives were considered and prototype testing was conducted, the existing effluent metering manhole was converted to house a spray-nozzle based, solar-powered air stripper, at a cost of approximately $20,000. About two-thirds of this cost was for the solar power system, which was initially designed to only provide power for 12 hours per day. Performance data are being collected and adjustments made to optimize the design, determine maintenance requirements, and establish power needs for continuous operation. Analytical data confirm the air stripper is sharply reducing concentrations of residual contaminants. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

A Conceptual Site Model for Nature and Extent of Contamination in a Riparian-Near Shore Area - 12410

The 100-K decision area is located along the Columbia River and includes source Operable Units (OUs), a groundwater OU, and the adjacent surface water, saturated sediment and aquatic biota. A conceptual site model (CSM) has been developed to evaluate concentrations of non-radiological substances and radionuclides detected in soil, water and sediments in a riparian near-shore area along the Columbia River. The CSM is used to determine if potential transport pathways exist to these media from Hanford Site sources by incorporating information from the physical system, surface hydrology, subsurface hydrogeology, analytical results, and ecological evaluation into the model. Six contaminants of ecological concern, mostly metals and non-radiological inorganics, have been identified in riparian and near-shore media. With few exceptions (notably chromium and hexavalent chromium), there are ambient sources for these constituents in soil, sediment and water that are unrelated to the Hanford Site. While the CSM documented analytical and biological conditions, this paper presents results focused on analytical measurements to document the potential for these contaminants to be related to a release from the Hanford Site. The purpose for preparing this CSM was to address, on a reactor decision area basis, the potential for Hanford Site contaminants in soil or groundwater to migrate to riparian or near-shore areas at concentrations that could be of concern for ecological receptors. This CSM supplements the analysis of River Corridor-wide ecological risks presented in the ecological risk assessment of the RCBRA. The RCBRA identified on a site-wide basis some contaminants of ecological concern that warranted further evaluation. Based on the results of the further evaluation contained in this CSM, with the exception of hexavalent chromium, detected concentrations of contaminants in riparian or near-shore media are not reliably detectable at levels of ecological concern, or are not associated with contamination in soil or groundwater resulting from Hanford Site operations. Therefore, for purposes of alternatives evaluation in the 100-K Feasibility Study, hexavalent chromium in groundwater should be considered the only contaminants of ecological concern. There are uncertainties in this evaluation related to analytical data quality. With the exception of most recently collected analytical data in groundwater, analytical methods had MDLs that were either close to or higher than aquatic criteria; when methods with adequate detection limits are used, the results show that contaminant concentrations are less than aquatic criteria. In many cases where analytical results were higher than aquatic criteria, it was determined that the results were based on unfiltered samples. Unfiltered analytical results are inappropriate for comparison with aquatic criteria; in general, filtered analytical results were less than aquatic criteria. In some cases where concentrations were reported higher than aquatic criteria, further evaluation of the data revealed it was qualified because of the presence of blank contamination. The analytical detection limit considerations and data quality issues further support the conclusion that contaminants concentrations in water were not reliably detected above levels of ecological significance. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Long-Term Stewardship at a Former Uranium Mill Tailings Site in Riverton, Wyoming - 17090

The US Department of Energy Office of Legacy Management (LM) is responsible for maintaining protective public health and environmental conditions at former uranium mill tailings sites nationwide via long-term stewardship. One of these sites, a former uranium mill near Riverton, Wyoming, is within the boundary of the Wind River Indian Reservation and operated from 1958 to 1963. Tailings and contaminated material associated with mill operations were removed and transported to an offsite disposal cell in 1989. The remedial action was completed under Title I of the Uranium Mill Tailings Radiation Control Act of 1978. Milling operations, which included an unlined tailings impoundment and an unlined evaporation pond, contaminated the shallow groundwater, resulting in a down-gradient groundwater plume that discharges to the Little Wind River. A natural flushing compliance strategy was implemented in 1998. This strategy allows contaminants of concern to naturally flush from the groundwater, provided that contaminants flush below US Environmental Protection Agency maximum concentration limits within 100 years. As part of the compliance strategy, LM has implemented a groundwater monitoring program along with institutional controls that include the installation of an alternate water supply, continued sampling of private wells, and restrictions on well drilling and gravel pit construction. LM works closely with local stakeholders and community members to ensure that these institutional controls are in place and maintained. The Riverton site provides an interesting case study where contaminant remobilization due to river flooding prompted a reevaluation of the conceptual site model to verify if the current compliance strategy would remain protective of human health and the environment. Concentrations of groundwater contaminants, which include sulfate, molybdenum, and uranium, were transiently elevated following flooding of the Little Wind River in 2010 and 2016. These flood events provided the impetus to investigate other aspects of the hydrologic system, including the unsaturated zone, naturally reduced (sulfidic) zones, and evaporite deposits. New site conceptual models, field and laboratory studies, and numerical models are being developed to explain how biogeochemical sediment-water interactions contribute to plume persistence and flood-related increases in groundwater concentrations. Updated human health and ecological risk assessments are progressing to evaluate the risk to human health and the environment based on current site conditions. Groundwater concentrations may remain above US Environmental Protection Agency maximum concentration limits beyond the 100-year natural flushing regulatory time frame. LM in its capacity as a long-term steward continues to monitor the site to ensure protectiveness is maintained and to determine the feasibility of alternative compliance and remediation strategies. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Dounreay Site's Interim End State-Environmental Safety Strategy - 17509

The Dounreay nuclear licensed site, located in Caithness on the north coast of Scotland, was the United Kingdom's (UK) site for Fast Reactor research and development. The Dounreay facilities are now being decommissioned and the site restored in accordance with UK Government policy to manage civil nuclear liabilities. This site closure and environmental restoration programme is to achieve levels of residual radiological and chemical contamination sufficiently low that the site will be safe for future use. This document sets out the Environmental Safety Strategy for the site remediation and closure programme, which will follow completion of facility decommissioning and demolition. The document summarises the contractual definition of the Dounreay site end states and also the associated regulatory regimes. An overview of the approach and processes for achieving the Interim End State (IES) are provided, along with consideration of how Dounreay will demonstrate that the IES has been achieved. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

FUSRAP Maywood Site Remediation of Redstone Park, Lodi, NJ - 17534

The Formerly Utilized Sites Remedial Action Program (FUSRAP) is the U.S. government program started in 1974 to identify, investigate and clean up or control sites that became contaminated as a result of the nation's early atomic programs. FUSRAP was administered by the U.S. Department of Energy (DOE) until 1997, when it was transferred to the U.S. Army Corps of Engineers (USACE) by congressional action. Redstone Park is a 1.5-acre municipal park located in a residential neighborhood in Lodi, Bergen County, New Jersey, USA. The park is a designated vicinity property of the FUSRAP Maywood Superfund Site. This paper will summarize the FUSRAP history of the property spanning over 20 years and then focus on the construction and community relations challenges of recent FUSRAP actions at the site. All of Redstone Park except for a portion bordering a residential property was remediated under FUSRAP in 1996. This remaining portion was remediated in 1998. The 1996 remediation included some hand-digging of surface contamination around the roots of several large mature trees in the park. As part of this action, the DOE proposed alternate cleanup standards whereby subsurface contaminated soil would remain in place around the root balls of the trees and in deeper areas (greater than 1.2 meters [m]) under a large storm drain pipe (or culvert) that runs through the park. This proposal was made to preserve the natural value of the trees and to protect the drainage pipe from damage. After careful review which included an assessment of potential health hazards, the U.S. Environmental Protection Agency (EPA) approved this proposal. The Borough of Lodi also supported the proposal as a way to preserve the trees for the enjoyment of park users. In 2009, EPA conducted a mandatory Five-Year Review of the FUSRAP Maywood Site. The review identified data gaps which prevented a full assessment of remedy effectiveness at Redstone Park. The USACE reviewed all the historic soil data from the park [1] and developed a characterization plan to address those gaps. Field surveys and sampling confirmed that the material around the tree roots and under the pipe did not comply with the current FUSRAP Maywood Site unrestricted use soil cleanup criteria (an average of 5 pico Curies per gram of radium-226 and thorium-232 combined above background) as established in the site's Soils and Buildings Record of Decision [2]. As noted earlier, USACE also considered the widespread uprooting of trees in the region during Hurricane Sandy in 2012 in its re-evaluation of the earlier decision to leave the trees in the park in place. That re-evaluation concluded it was in the best interest of all stakeholders to remove the residual contamination in Redstone Park. USACE subsequently excavated the soil under and around the drainage pipe as Phase 1 of a two-phased approach to address this residual contamination. 1,116 cubic yards of soil were removed for safe offsite disposal during this action in June-July 2016. Phase 2 (removal of contaminated soil around the tree roots) began in September 2016 with expected completion by December 2016. The work was staged in two phases so as not to impact the park during the summer school vacation months when park use is heaviest. (authors)

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

The radium industry in France and the remediation of polluted sites - 15256

According to the French Law of 28 June 2006 relative to the management of radioactive materials and waste, Andra is in charge of a public service mission that involves the clean-up of orphan sites that have been polluted by radioactivity. Andra is currently working, or has worked in the past, on around thirty sites in mainland France. The clean-up strategy is selected after a comparative analysis of the cost and the advantages of the different scenarios based on the ALARA principle. Whenever reasonable, Andra tries to achieve total clean-up, so that the site can be re-used without any constraint. However, for certain cases, it is opted for a less ambitious scenario, which means restricting the possibilities of use of the site after clean-up. In all cases, the chosen scenarios guarantee that there will be no radiological impact on the planned new use of the site. If the site is an orphan site, a National Advisory Committee for Public Funding in the field of Radioactivity (known as CNAR) decides which scenario presents the best cost-benefit profile and whether to provide public subsidies to fund the work. The multidisciplinary composition of the CNAR, with members from public administrations and organizations, politicians, qualified personalities and non-governmental organizations, guarantees a decision that has been carefully considered from all aspects. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
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

Planning large-scale excavation and construction activities within an aerially constrained site for construction of a repository for low and short-lived intermediate level radioactive waste at the Bulgarian national disposal facility - 15372

The Bulgarian State Enterprise for Radioactive Waste Management (SERAW) is planning the construction of a near-surface repository for low and short-lived intermediate level radioactive waste, the National Disposal Facility (NDF), at the Radiana Site adjacent to the Kozloduy Nuclear Power Plant (KNPP). The Site, a rectangular area approximately 1.2 km east-west by 0.4 north-south, is located on a slopping area between the second and sixth loess terraces above the River Danube with elevations ranging from approximately +40 m to elevation +95 m. Construction of the NDF will be divided into three phases separated by approximately 20 years each. The first phase will see the construction of the primary support facilities, referred to as the Auxiliary Buildings and including the Waste Reception and Buffer Storage (WRBS) Building, and the first set of 22 reinforced concrete disposal cells and supporting infrastructure, including a network of subsurface observation galleries, the Infiltration Network Control (ICN) Galleries. Each disposal cell will be 20.15 m long by 17.05 m wide by 9.45 m in height. The disposal cells will be arranged in two parallel rows. Disposal activities will be conducted using overhead cranes installed inside of track mounted mobile roofs. Each row of disposal cells will be serviced by one mobile roof. The mobile roofs will be supported by massive concrete foundations. Construction at the site will present several logistical challenges that will need to be overcome to fully realize the NDF. First in order to begin construction of these facilities nearly 1 million 3 of soil will require excavation and handling. Consistent with requirements to minimize potential environmental impacts identified in the site Environmental Safety Assessment (EIA) excavated soil will, to the extent possible, remain onsite. Approximately three quarters of the soil can be accommodated within the site boundaries. Another challenge results from requirements imposed by the ground conditions. The sub-grade at the site, which consists primarily of loess, will require considerable improvement. To this end a 5 m thick loess-cement cushion will be constructed across much of the site. Specifically, the cushion will be required beneath the disposal cells and the WRBS Building. Construction of the loess-cement cushion in the disposal area will require detailed planning and coordination, particularly as the cushion beneath the disposal cells also contains embedded structures, including the ICN Galleries as well as massive concrete foundation beams required for the two mobile roofs. Construction of these structures will require planned interruptions in the construction of the loess-cement cushion. Specific cement types and strict quality requirements will be required for completion of the loess-cement cushion as well as for completion of the ICN Galleries. The construction planning will need to account for the large volumes of soil to be excavated as well as ensuring sufficient material supplies in terms of both quality as well as quantity. Large quantities of materials including both dry cement for mixing with the loess, and wet concrete for pouring of the mobile roof foundations are accounted for by the plan. However, even after completion of these activities additional challenges are addressed by the plan related to the contemporaneous construction management of the auxiliary buildings and the disposal cells. (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

Endpoint Evaluation for 200-PW-1 Operable Unit Soil Vapor Extraction, Hanford Site, Washington - 16478

On the Central Plateau of the Hanford Site in semi-arid southeast Washington State, the 216-Z-9 Trench, 216-Z-1A Tile Field, and 216-Z-18 Crib were used from 1955 to 1973 for soil column disposal of liquid wastes containing carbon tetrachloride. The geological setting underneath these disposal areas consists of an approximately 70 m thick vadose zone with a nominally 5 m thick low-permeability layer at a depth of 30 m. Infiltration of the liquid waste through the vadose zone to the groundwater was driven by the liquid volume introduced during disposal. Carbon tetrachloride readily volatilises in the vadose zone, making soil vapor extraction (SVE) the preferred remediation technology. Between 1992 and 2012, SVE recovered 80,107 kg of carbon tetrachloride from the vadose zone below the three waste sites. Of this total recovery, 93 percent was removed during the first 5 years of operations. The last 7 percent was recovered in the last 16 years of operation. In 2011, a final cleanup level of 100 ppmv for carbon tetrachloride in soil vapor was established in the record of decision for the 200-PW-1 Operable Unit, which includes the three carbon tetrachloride waste sites. The final cleanup decision specified that soil vapor concentrations and the cleanup level would be further refined and assessed in the future to ensure groundwater protection. A subsequent treatability test was conducted and the results were used to further refine the definition of vadose zone source conditions that are protective of groundwater. Based on this treatability test, predictions indicate that current and future vadose zone conditions will meet groundwater protection objectives. SVE operations were not performed in 2013, 2014, and 2015, and soil vapor concentrations in all SVE wells (and all but two monitoring probes installed using direct-push technology) remained below the 100 ppmv cleanup level during this time. SVE endpoint guidance was prepared in 2013 as a joint effort between Pacific Northwest National Laboratory, U.S. Army Corps of Engineers, and U.S. Environmental Protection Agency. This SVE guidance was used to develop a path forward for the 200-PW-1 Operable Unit SVE remedy. The guidance asks the following questions: 1. Are data collected to date adequate to support a well-defined conceptual site model? 2. Have remediation goals (cleanup levels) been defined? 3. Are environmental pathways and risk understood well enough to support site closeout? 4. Will remaining contamination in the vadose zone cause groundwater cleanup levels to be exceeded? If the answer to the first three questions is 'Yes', and the answer to the fourth question is 'No', then the site is ready for closure. At this time, the site has compiled appropriate information to answer these questions to support a remedy decision to terminate SVE operations. The U.S. Environmental Protection Agency recently provided concurrence that termination of SVE operations within the 200-PW-1 Operable Unit is appropriate. (authors)

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

Final Surrender of Radioactive Substances (Environmental) Permits on UK Nuclear Licensed Sites - 16646

This paper is split into three, linked, parts; each part explains work being taken forward by the United Kingdom (UK) Government and/or the nuclear site regulators to apply proportionate regulatory controls before, during and after nuclear site decommissioning and clean-up. Part I of the paper describes work led by UK Government to examine credible options for a step-wise removal of those safety, security and environmental protection regulations that apply to nuclear site decommissioning and clean-up. Any removal of regulations will have to take due account of and be proportionate to the residual risk following cessation of all clean-up works. Part II of the paper describes the approach used by the UK Environment Agencies to regulate final site clean-up of UK nuclear licensed sites. Ultimately, clean-up will result in nuclear sites being released from radioactive substances regulation. Part III of the paper links Parts I and II of the paper together by describing how the UK Environment Agencies will apply proportionate regulation to the clean-up of the 140-acre Dounreay site in Caithness which is the largest nuclear clean-up project in Scotland and the second largest in the UK, after Sellafield. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Remediation Strategy for Former PChP Uranium Production Site in Ukraine - 18217

The paper describes current status and results of the investigation carried out at the one of the largest Uranium production facilities in the former Soviet Union (SU) located in Ukraine, 'Pridneprovsky Chemical Plant' (PChP). A large volume of new site specific contamination data and parameters needed for safety assessment, prioritization and environment remediation planning have been received during different phases of the site characterization and hazards investigation, carried out in the frame of State remediation programs and also with financial support of the EC projects during 2009-2017. Specific features of this site are significant amount of sludge materials, containing high activity concentration of {sup 230}Th and also number of the buildings, which were used for Uranium production in past and now containing large amount of spilled and dispersed U-residues with very high activity concentration of {sup 226}Ra, {sup 230}Th - as well as other radionuclides of {sup 238}U decay series, which also remain in many locations at this site. This site is still used for industrial purposes, which are not related to the Uranium production, and therefore many people are visiting this site daily, posing potential high risks for them to be exposed. The paper presents the understanding about the identified hazards and the priority between number of many other objects, which are required for the remediation, and also describes the problems faced during remediation planning because lack of safety management, experience and technical capabilities as well as funds available in Ukraine, which are needed to bring PChP site in safe conditions. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Mercury Recovery at Former Lithium Production Site at the Miramas in France - 18529

The former Lithium production facility located at Miramas in the South-East of France recently completed a 10-year program of process equipment removal, building demolition and soil remediation to recover mercury (Hg) that had been lost during operations at the site. After over 100 years ago chemical production, all production activities stopped in 2009, and immediately afterwards the clean-up project began. The main project focused on the demolition of all facilities and the decontamination of building materials and soil clean-up, with the goal of remediating the site for future industrial purposes. Prior to starting the decommissioning and clean-up work at the site a detailed site survey was conducted to identify the extent of the contamination of the site. After investigations into available technologies, the decision was made to install on-site treatment processes. This resulted in fewer residual environmental effects (trucking pollution, shipping containers, volume of materials, etc), a reduction in logistic complications, and, importantly, was cost effective compared to sending all untreated material to external processing facilities. This decision resulted in a need to optimize demolition waste management, while ensuring the highest clean-up and safety levels. A variety of treatment processes were investigated and compared and two technologies were finally selected and implemented. The first process was a 'thermal desorption unit (TDU),' which heated excavated soils and captured the vaporized mercury. The second was a washing process that was used to remove surface contamination. After the contaminated areas were excavated, materials were crushed, screened and sorted into different sizes, with each pile being routed to the appropriate process. The smaller-sized particles were treated in the TDU. A batch of around 12 MT was fed into a moisture evaporator and then into a mercury evaporator. The soils were then cooled, sampled to ensure no residual Hg contamination before being mixed with a binding agent, and returned to the excavation site. Larger materials with surface contamination were washed to remove the contamination. The liquid effluents were sent to a tank where the contaminated fines were removed, dried, pressed and sent for processing. If the washed, coarse materials failed to reach acceptable mercury levels, they were crushed again and sent to be treated in the TDU. The washing fluid was recycled for the next batch. (author)

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

A Preliminary Probabilistic Performance Assessment Model for Radiological and Chemical Contamination at the West Valley Site, New York - 19295

The New York State Energy Research and Development Authority (NYSERDA) is the owner of the Western New York Nuclear Service Center (WNYNSC), a 1,351-ha site located approximately 48 km south of Buffalo, New York. In 1962, Nuclear Fuel Services, Inc. (NFS) entered into agreements with the Atomic Energy Commission and New York State to construct the first commercial reprocessing plant of nuclear fuel in the United States at the WNYNSC. NFS built and operated the spent fuel reprocessing plant and waste disposal facilities, processing 640 Mg (640 metric tons) of spent nuclear fuel from 1966 to 1972 under an Atomic Energy Commission license. Nuclear fuel reprocessing operations halted in 1972 and never restarted, leaving behind radioactive and chemical wastes. The reprocessing wastes include high-level waste (HLW), so U.S. Department of Energy (DOE) was compelled to complete certain waste management activities under the West Valley Demonstration Project (WVDP) Act of 1980, including decommissioning of WVDP facilities. As collaborating agencies, NYSERDA and the DOE are tasked with making decisions about decommissioning and risk reduction for the West Valley Site. Neptune and Company, Inc. (Neptune) was contracted to develop a probabilistic performance assessment (PPA) model to assist the agencies in their decision making process for decommissioning the WVDP and WNYNSC. One important tool that is needed in order to inform the decision-making process is a science-based model of the contamination at the West Valley Site and its potential implications for human health and the environment. The West Valley PPA Model (the Model), developed using the GoldSim modeling software, is a tool intended to provide support for decision making with uncertainty, in a manner that is transparent, defensible, and robust. The PPA Model includes contaminant transport and health effects components, and is organized around geographically-organized contaminated facilities. These include the waste disposal areas licensed by the U.S. Nuclear Regulatory Commission and the State of New York, a waste tank farm for storage of HLW resulting from reprocessing operations, and several areas contaminated with radioactive and chemical constituents. The Model evaluates contaminant transport from these sources to points of exposure across the site and into receiving surface waters and sediments. Hypothetical people and wildlife are exposed to contamination at these locations, and the effects of these exposures are evaluated. Contaminant transport processes to be evaluated in the Model include groundwater and surface water transport, contaminant translocation by plants and animals, diffusion in subsurface air and water, and erosion of the Site. The evaluation of exposures to people in this preliminary model is limited to a resident farmer scenario, and ecological assessment is performed at the level of a screening analysis. The results of these preliminary evaluations inform future model developments. Model results are subjected to sensitivity analysis in order to determine those pathways and parameters that are most significant in influencing the results. This information allows analysts and decision makers to focus on those aspects of Site behavior and processes that contribute most to overall uncertainty. With this information, the Supplemental Environmental Impact Statement (SEIS) can inform defensible decisions regarding remediation of the Site. (authors)

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

A GIS-Based Suitability Analysis of a Phytomanagment Strategy for TCE in Groundwater and Soil Niagara Falls Storage Site, New York - 19385

The large number of complexly contaminated sites throughout the nation has propagated the application of phytoremedial techniques in a wide array of environmental remediation strategies. The use and breeding of vegetation for the in-situ treatment of environmental media (soil, groundwater, sediment) contaminated with organic or inorganic contaminants has shown to provide a low-cost alternative to conventional means of remediating contaminated sites (e.g., groundwater extraction, chemical oxidation or reduction, bioremediation, excavation, etc.). One impediment to effective phytoremediation is the selection of proper plant-species, which is complicated due to the many variables that are required for plant-species viability (i.e. range of soil pH, annual precipitation values, depth to groundwater table, etc.). This study employed the use of a Geographic Information Systems (GIS) to first define the spatial extent of contaminated media (soil and groundwater) at a project site and then support an effective means to optimize phytoremediative techniques to manage these impacts prior to final remediation. Spatial analyses and analytical calculations were coupled to determine an optimal plant species and spacing to maximize the effectiveness of a phytomanagement plan. The incorporation of fuzzy membership functions and fuzzy overlay provide an innovative method to help select the optimal plant-species for phytomanagement planning. Fuzzy membership functions were used to represent the plant growth requirements and provided an intuitive method to represent the uncertainty associated with plant-growth requirements. The fuzzy overlay function then employed a raster-based suitability analysis that together provided decision makers with a scientific solution to optimally design a phytomanagement strategy for site-related volatile organic compound (VOC) impacts. The Niagara Falls Storage Site (NFSS) VOC-impacted groundwater is contained in clayey glacial sediments, which commonly are technically impractical to remediate. Prior on-site studies show that native poplar (cottonwood variants) preferentially translocate or phytoextract the VOCs from the site soils and thus provide a proven mechanism to manage the multi-media impacts. Consequently, the Army Corps of Engineers Buffalo District evaluated phytoremediative approaches as a passive tool to manage the VOCs during the project life cycle prior to final remediation. The fuzzy membership functions and fuzzy overlay modeling of candidate species narrowed the selection to an optimal species and subsequent transpiration modeling estimated the plant spacing for the overall phytomanagement plan. The method employed for this study is easy applied to other phytoremediative and phytomanagement actions derived from hazardous waste decision making. (authors)

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