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At least 1,081 records · Page 60

Innovative Strategies for Long-Term Monitoring of Complex Groundwater Plumes at DOE’s Legacy Sites (Workshop Report)

Most remaining Department of Energy (DOE) sites will require extended periods of institutional control, especially at complex groundwater sites where attenuation-based strategies have been implemented to facilitate closure. The current practice of monitoring—obtaining and analyzing contaminant concentration in groundwater samples at numerous wells—will account for a large portion of the projected life-cycle at these DOE sites unless a new approach is adopted. State-of-the-art technologies are being developed, including in situ sensors, geophysics, radiation mapping, numerical modeling and AI/ML. These technologies can optimize monitoring strategies in space and time, provide spatially extensive information at vulnerable regions and/or provide more continuous monitoring at lower cost. As part of DOE’s Office of Environmental Management (DOE-EM’s) efforts to advance long-term monitoring systems, an in-person/virtual hybrid workshop was hosted by Savannah River National Laboratory (SRNL) on January 24 and 25, 2023, in Augusta, Georgia. Because DOE-EM’s complex sites will eventually be transferred to DOE’s Office of Legacy Management (DOE-LM), representatives of DOE-LM were important participants in the workshop. The purpose of the workshop was to identify challenges and opportunities for deploying advanced technologies for long-term monitoring at DOE sites. The key questions during the workshop were: 1) the regulatory acceptance of replacing a process that traditionally has used laboratory sampling and analysis of groundwater samples, and 2) the application of this strategy to the southwestern arid sites that include many of the remaining DOE-EM and DOE-LM complex groundwater plumes. Characteristics common to most arid sites present both limitations and opportunities for advanced technologies. DOE-EM has funded a National Laboratory team from SRNL, Lawrence Berkeley National Laboratory (LBNL), and Pacific Northwest National Laboratory (PNNL) to establish the overarching framework of long-term monitoring by systematically combining advanced hardware and software technologies. This project is titled “Advanced Long-Term Environmental Monitoring Systems (ALTEMIS)” and is sponsored by the DOE-EM Technology Development Program. The multi-laboratory team is currently developing and testing innovative monitoring strategies, including the use of in situ groundwater sensors, geophysics, drone/satellite-based remote sensing, reactive transport modeling, and artificial intelligence/machine learning (AI/ML). The project’s demonstration testbed is at the Savannah River Site (SRS) F-Area Seepage Basins, where a well-characterized complex groundwater plume composed of uranium and other radionuclides is in the latter stages of remediation. The workshop included more than 70 participants, presentations, a field visit to F-Area, breakout working groups, and large group discussion. Participants developed recommendations on five topics: in situ sensors, spatially integrative tools, challenges to regulatory acceptance, AI/ML strategies, and transitioning sites to DOE-LM.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

A Characterization Study of Reactive Sites in ALD-Synthesized WOx/ZrO2 Catalysts

A series of ZrO2-supported WOx catalysts were prepared using atomic layer deposition (ALD) with W(CO)6, and were then compared to a WOx/ZrO2 catalyst prepared via conventional impregnation. The types of sites present in these samples were characterized using temperature-programmed desorption/thermogravimetric analysis (TPD-TGA) measurements with 2-propanol and 2-propanamine. Weight changes showed that the WOx catalysts grew at a rate of 8.8 × 1017 W atoms/m2 per cycle. Scanning transmission electron microscopy/energy-dispersive spectroscopy (STEM-EDS) indicated that WOx was deposited uniformly, as did the 2-propanol TPD-TGA results, which showed that ZrO2 was completely covered after five ALD cycles. Furthermore, 2-propanamine TPD-TGA demonstrated the presence of three types of catalytic sites, the concentrations of which changed with the number of ALD cycles: dehydrogenation sites associated with ZrO2, Brønsted-acid sites associated with monolayer WOx clusters, and oxidation sites associated with higher WOx coverages. The Brønsted sites were not formed via ALD of WOx on SiO2. The reaction rates for 2-propanol dehydration were correlated with the concentration of Brønsted sites. While TPD-TGA of 2-propanamine did not differentiate the strength of Brønsted-acid sites, H–D exchange between D2O and either toluene or chlorobenzene indicated that the Brønsted sites in tungstated zirconia were much weaker than those in H-ZSM-5 zeolites.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Exopaleontology at The Pathfinder Landing Site

The Mars Pathfinder Mission is a Discovery Class mission that will place a small lander and rover on the surface of Mars in July of 1997. It is primarily a technology demonstration to test the feasibility of a direct entry-delivery system, but carries a nominal scientific payload that includes rover-lander and instrumentation for limited mineralogical analysis. The nominal landing site was selected by the Pathfinder Team under the leadership of Dr. Matthew Golombek (JPL) based input from 60 participants at a Landing Site Workshop held last Spring at the Lunar Planetary Institute in Houston. The mission constraints for the landing site were 0-30 deg. N latitude, and below the 0.0 elevation datum. Over 20 landing sites were proposed and a nominal site was selected on southern Chryse Planitia near the terminae of the Ares and Tui outflow channels. In part, the decision to land at this location was based on the opportunity to sample a potentially large number lithologies in a small area (the rover will have a range of a few tens of meters from the lander). The purpose here is to review the general geological context of the landing site and the rationale for Exobiology's recommendation of the Ares site given at the workshop last spring. Because Ares and Tui Valles are sourced within terranes that may have originated by thermokarst processes, hydrothermal processes could have operated there for some time. Hydrothermal systems are presently regarded as important sites for a fossil record on Mars. Models for the formation of the outflow channels suggest that thermal spring sinters and associated aqueous mineral deposits, high priority targets for Mars Exopaleontology, could have formed in association with thermokarst processes and subsequently been delivered to the landing site in large quantities during the periodic cataclysmic outflows that created the channels.

Farmer, Jack D.↗

Selection of the Final Four Landing Sites for the Mars Exploration Rovers

Engineering constraints developed for the Mars Exploration Rovers (MER), their translation into ~185 potential landing sites and their downselection to 6 high priority science sites have been described [1, 2]. These 6 sites (Meridiani-previously referred to as Hematite, Gusev, Isidis, Melas, Eos, and Athabasca) were evaluated in detail as to their science potential and safety, relative to specific engineering constraints, at the 3rd MER Landing Site Workshop held March 26-28, 2002 in Pasadena, CA. This abstract describes: (1) the evaluation of these 6 sites, (2) the removal and reprioritization of sites following this workshop, (3) the identification of a low-wind site in Elysium, (4) the final 4 sites being considered for landing the 2 MER and (5) their evaluation at the 4th MER Landing Site Workshop held January 8-10, 2003 in Pasadena, CA [3].

Golombek, M.↗

Comparison of the Sensitivity of Surface Downward Longwave Radiation to Changes in Water Vapor at Two High Elevation Sites

Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 kilometers apart horizontally and 348 meters vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR-q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here.

elevation↗

Validation of SMAP Surface Soil Moisture Products with Core Validation Sites

The NASA Soil Moisture Active Passive (SMAP) mission has utilized a set of core validation sites as the primary methodology in assessing the soil moisture retrieval algorithm performance. Those sites provide well calibrated in situ soil moisture measurements within SMAP product grid pixels for diverse conditions and locations.The estimation of the average soil moisture within the SMAP product grid pixels based on in situ measurements is more reliable when location specific calibration of the sensors has been performed and there is adequate replication over the spatial domain, with an up-scaling function based on analysis using independent estimates of the soil moisture distribution. SMAP fulfilled these requirements through a collaborative CalVal Partner program.This paper presents the results from 34 candidate core validation sites for the first eleven months of the SMAP mission. As a result of the screening of the sites prior to the availability of SMAP data, out of the 34 candidate sites 18 sites fulfilled all the requirements at one of the resolution scales (at least). The rest of the sites are used as secondary information in algorithm evaluation. The results indicate that the SMAP radiometer-based soil moisture data product meets its expected performance of 0.04 cu m/cu m volumetric soil moisture (unbiased root mean square error); the combined radar-radiometer product is close to its expected performance of 0.04 cu m/cu m, and the radar-based product meets its target accuracy of 0.06 cu m/cu m (the lengths of the combined and radar-based products are truncated to about 10 weeks because of the SMAP radar failure). Upon completing the intensive CalVal phase of the mission the SMAP project will continue to enhance the products in the primary and extended geographic domains, in co-operation with the CalVal Partners, by continuing the comparisons over the existing core validation sites and inclusion of candidate sites that can address shortcomings.

SMAP↗

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites

Abstract Aeolian processes have likely been the predominant geomorphic agent for most of Mars' history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The downselected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The downselected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low. Plain Language Summary Wind-blown dune sand can wear away the Martian surface and uncover

Rover↗

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites

Aeolian processes have likely been the predominant geomorphic agent for most of Mars’ history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The down selected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The down selected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low.

Matthew Chojnacki↗

Adaptative Site Management for a 115 Acre Chlorinated Solvent Plume with Two Separate Source Areas at Kennedy Space Center, Florida

Background/Objectives. During Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) activities, Geosyntec delineated a chlorinated volatile organic compound (CVOC) plume at the National Aeronautics and Space Administration’s (NASA’s) Vehicle Assembly Building (VAB) area located at KSC, Florida. The RFI activities identified an approximate 115-acre dissolved plume (primarily vinyl chloride) and a trichloroethene (TCE) source area in an active aerospace complex that is surrounded by sensitive wetland/waterbodies. Due to the size of the impacted area, the Corrective Measure Design included a multi-component strategy: (i) address the source area via bioremediation; (ii) protect sensitive wetlands from impacted groundwater discharge via biosparging; and (iii) Long Term Monitoring (LTM) of the remaining dissolved plume. After the Corrective Measures implementation (CMI), NASA and Geosyntec worked with Florida Department of Environmental Protection (FDEP) to implement an adaptive site management for the complex, 115-acre site outside of the traditional RCRA process. The adaptive site management approach relied on performing supplemental assessments and implementing Interim Measures (IMs) to further assess and implement remedies over time while working within site and budget constraints, with an overall goal of achieving enough mass reduction to transition the entire site to LTM and eventually achieve site closure. Approach/Activities. After the biosparge barrier was operational and bioremediation within the source area (referred to as Hot Spot 1) achieved the Corrective Action Objective (CAO), supplemental assessment of the area between Hot Spot 1 and the biosparge barrier was performed. The conceptual site model was updated using the supplemental assessment results and an air sparge system IM was designed to treat an approximate 1.2 acre area (referred to as Hot Spot 2). After installation of the air sparge system, supplemental assessment within the remainder of the 115-acre dissolved plume was performed and a second TCE source area was identified. The TCE source area and associated areas with elevated CVOC concentrations (referred to as Hot Spot 3) were delineated and a bioremediation IM was implemented. Also, the downgradient impacts from Hot Spot 3 were adjacent to a sensitive waterbody, and negotiations with the FDEP allowed the area to be monitored using LTM. Results/Lessons Learned. The performance of supplemental assessment activities and implementation of remedial alternatives as IMs allowed NASA to successfully address groundwater impacts over time, while working within the FDEP regulatory framework. The implementation of the CMI and multiple IMs has achieved the following goals: (i) the biosparge barrier has mitigated the potential discharge of impacted groundwater to an adjacent wetland; (ii) enhanced bioremediation within Hot Spot 1 achieved the CAO within 2 years and transitioned the area into LTM; (iii) operation of an air sparge system within Hot Spot 2 removed TCE as a constituent of concern and contributed to a reduction (approximately 43%) in the impacted groundwater area outside the air sparge treatment area (plume collapse); and (iv) bioremediation within Hot Spot 3 removed approximately 80% of the CVOC mass and contributed to a reduction (approximately 47%) in the impacted groundwater area outside the bioremediation IM treatment area. Overall, the adaptive approach is protecting the sensitive water bodies surrounding the complex site and reducing the area of impacted groundwater, which is moving the entire site towards LTM.

Rebecca C Daprato↗

Thermal interaction effect on nucleation site distribution in subcooled boiling

An experimental work on subcooled boiling of refrigerant, R134a, to examine nucleation site distributions on both copper and stainless steel heating surfaces was performed. In order to obtain high fidelity active nucleation site density and distribution data, a high-speed digital camera was utilized to record bubble emission images from a view normal to heating surfaces. Statistical analyses on nucleation site data were done and their statistical distributions were obtained. Those experimentally observed nucleation site distributions were compared to the random spatial Poisson distribution. The comparisons showed that, rather than purely random, active nucleation site distributions on boiling surfaces are relatively more uniform. Experimental results also showed that on the copper heating surface, nucleation site distributions are slightly more uniform than on the stainless steel surface. This was concluded as the results of thermal interactions between nucleation sites with different solid thermal conductivities. A two dimensional thermal interaction model was then developed to quantitatively examine the thermal interactions between nucleation sites. The results give a reasonable explanation to the experimental observation on nucleation site distributions.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Interface Capturing Simulations on Pool Boiling Performance With Multiple Nucleation Sites

High-fidelity pool boiling simulations can provide a numerical database for improving mechanistic boiling models by allowing for specific evaluation of interactions among bubbles. Previously published pool boiling simulations investigated two nucleation sites in which bubble growth at one site suppressed nucleation at the other site. Based on previous study results, more complicated interface-capturing simulations on pool boiling were conducted using PHASTA code with locally refined unstructured mesh.First, different boundary conditions (BCs) were assessed to support robustness and reproducibility of the boiling model. Then, a scale study was conducted at a larger domain with nine nucleation sites, four of which were activated. Involving more nucleation sites increased the complexity of bubble interactions from surrounding sites. Finally, bubble departure behavior influenced by wall heat flux was investigated. When heat flux was increased, the order of bubble departure changed, but diagonal bubbles always departed after one another. The departure time interval between the first and second bubble reduced as heat flux increased. The corresponding frequency was almost linearly proportional to the heat flux. In addition, bubble departure behavior was found to be greatly influenced by the nucleation site pattern. Multiple nucleation sites resulted in superimposed inhibitive effects from surrounding sites to each bubble, which extensively delayed the departure.The work presented here provides new insight on the fundamental understanding of boiling phenomena, contributes to the development of a 3D multiphase computational fluid dynamics (M-CFD) model, and provides a more comprehensive database for data-driven pool boiling studies.

Fan, Joy↗

Challenges in Obtaining Property Access: The FUSRAP Maywood Site Experience - 13433

The Formerly Utilized Sites Remedial Action Program (FUSRAP) is the US 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. Many of these sites are not owned by the federal government and therefore require owner permission to enter. The experience in pursuing such access at the FUSRAP Maywood Superfund Site (the Maywood Site or the Site) in Bergen County, New Jersey, is extensive. Since the US Army Corps of Engineers (the Corps) assumed responsibility for the Maywood Site from the US Department of Energy in 1997, at least 186 separate property access agreements (known in FUSRAP as a Real Estate Right-of- Entry or ROE) have been executed between the Corps and approximately 55 different land owners and tenant occupants at the Maywood Site (agreement renewals with the same owners over time account for the difference). Maywood's experience during the Corps' tenure, reflected here in three case studies of representative property access efforts, offers some lessons and best practices that may apply to other remedial programs. While the Site Community Relations Manager (the author of this paper) managed the property access task, multi-disciplinary support from across the project was also critical to success in this endeavor. (authors)

54 ENVIRONMENTAL SCIENCES↗

Ecological Resource Value, Remediation Options, and Impacts: Functional Remediation at Hanford Site - 17226

Governmental agencies, Tribes, regulators, resource trustees and other stakeholders are interested in understanding the risk to the environment from remediation and restoration, particularly at large DOE sites with complex remediation tasks lasting decades. While each remediation project has the usual environmental impact assessment that include risk to eco-receptors, a piece-meal approach to examining the effect of remediation does not provide an overview of remaining tasks that would aid in sequencing these tasks. The Consortium for Risk Evaluation with Stakeholder Participation (CRESP) developed a risk methodology for Hanford Site that included ecological resources between 2014 and 2015. The ecological methodology included a comparison of the value of on-site resources with the eco-region, with state and federal threatened and endangered species, and with rare and unique habitats. Potential remediation options for particular evaluation units were used in conjunction with the resource level values to determine the risk of remediation of ecological resources. The methodology developed for Hanford Site also considered functional remediation (e.g. number of trucks, personnel, heavy equipment), initiating events (e.g. earthquakes, volcanos) and future land use. These factors were combined to rate the risk to ecological resources on a scale of not-discernible to very high. In this paper seven evaluation units (waste sites requiring remediation) were evaluated to explore the efficacy of the methodology to provide useful information on the comparative risk for decommissioning and waste management sites. The evaluation of resource levels was based on prior site information, state and federal data bases, and field investigations. The final determination of a risk rating for each evaluation unit depended upon both quantitative data, field experience, and professional judgement. It provides a method that can be applied to many remediation sites within a large DOE facility such as Hanford, as well as across the DOE complex. This will provide information for sound decision-making with stakeholder participation, and will allow DOE to reassure stakeholders that they are protecting human and ecological health on the Hanford Site. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Evaluation of Story Maps to Enhance Public Engagement and Communication at Legacy Management Sites - 17334

The US Department of Energy's Office of Legacy Management's (LM) mission is to fulfill the department's post-closure responsibilities and to ensure protection of human health and the environment. Accomplishing that mission currently requires managing 91 legacy sites across the country by performing efficient long-term surveillance and maintenance activities, preserving and making accessible historic site records, and identifying opportunities for beneficial reuse. Integral to the success of these activities is connecting and effectively communicating with the public, governments, and other interested parties. Relationships with such entities are so important that the Office of Legacy Management has elevated such engagement to one of its strategic goals for the next 10 years. Several public engagement efforts are currently supported, including stakeholder meetings, interpretive visitor centers, hard-copy documents, and Internet-based information sources. The tools available to communicate with the public via the Internet are continually improving, and LM proactively evaluates these tools to enhance public engagement. The use of ESRI Story Maps to effectively and more succinctly communicate LM's long-term surveillance and maintenance practices is one tool currently being evaluated. Story Maps can utilize multiple types of content to engage users through site narratives, illustrations of change over time, photos, videos, and embedded links to external sources of information. The ability to illustrate site complexities via graphics and geo-spatial data is particularly useful for staff as well as communicating to stakeholders. Staff with a variety of expertise and functions in the organization can be empowered to respond to stakeholder questions using this tool. In addition, Story Maps can be easily initiated and managed in real time by LM site managers, an efficiency that would be invaluable to them as immediate site communication needs arise. A series of test Story Maps for several sites were developed to explore the capabilities of the tool. The test Story Maps included pages that described site description and overview, historical conditions and use, cleanup conditions, current monitoring data if applicable, and institutional controls. Links to existing communications tools were also incorporated in Story Maps, such as existing web sites that currently store environmental reports and the Geo-spatial Environmental Mapping System (GEMS), where stakeholders can download monitoring data. As with any tool, many things must be taken into consideration, such as: 1) Can the current IT infrastructure support the tool? 2) What data quality protocols need to be established? 2) What resources will be needed to maintain this tool? 3) What type of information should be shared? 4) Who will be responsible for information updates? This paper explores potential approaches for developing and deploying this tool for the public. (authors)

61 RADIATION PROTECTION AND DOSIMETRY↗

Hydrogeologic modeling and the development of preliminary remediation goals for the Guterl Specialty Steel Site, New York - 15431

The Former Guterl Specialty Steel Corporation Site (Guterl Site) is located 32 kilometers (20 miles) northeast of Buffalo, New York, in Lockport, Niagara County, New York. Between 1948 and 1952, up to 15,875 metric tons (35 million pounds) of natural uranium metal (U) were processed at the Guterl Site. The resulting milling dust, shavings, thermal scale, and associated on-site land disposal contaminated both the facility and soils. These combined manufacturing and disposal processes promoted the development of a large-scale uranium plume in the groundwater underlying the site. Site soils are anthropogenic fill and re-worked, glacially-derived sediments that vary between 0.6 meters (m) and 3 meters (2.0 to 10.0 feet [ft]) in thickness. These soils blanket a highly permeable weathered and fractured zone in the upper Lockport Dolostone bedrock. Aerial recharge through the thin soils flushes soluble constituents to groundwater, as exemplified by variations in specific conductivity and groundwater levels in the bedrock during precipitation events. Seasonally higher groundwater levels also promote contact with uranium contamination in deeper soil, thus complicating the transport characteristics of the site (e.g., oxidizing metallic uranium in the soil that increases leach rates). The Seasonal Soil (SESOIL) compartment model was used to simulate a series of site soil conditions and predict the leaching of uranium to groundwater. The SESOIL input included physical soil characteristics, uranium profiles common in five soil areas, climate data, and an assumed oxidation-state (or chemical valence) for metallic uranium in the soil. The iterative modeling process evaluated site-specific variables to achieve a final deterministic set of input that was applied to the five soil areas. The leaching simulations estimated time-dependent influx rates for uranium, which were input to a numerical groundwater flow (MODFLOW) and transport (MT3DMS) model. The combined modeling effort produced spatially and temporally variable transport conditions that were simulated over a 1,000-year period. The leaching models predicted a preliminary remediation goal (PRG) for uranium of 11 milligrams per kilogram (mg/kg) that is protective of groundwater. However, this low uranium PRG has field implementation concerns, so a modified direct-exposure PRG of 70 mg/kg was developed and evaluated in the flow and transport model. The primary difference in the PRGs is the longevity and location of the uranium plume, which will affect the remedial costs and potential stakeholder acceptance. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Niagara Falls Storage Site - Balance of plant investigation results - 15432

The Niagara Falls Storage Site (NFSS) is a 77.3-hectare (ha) (191-acre) property that is owned by the United States Government and located in the township of Lewiston, Niagara County, New York. The NFSS is part of the former Lake Ontario Ordnance Works (LOOW) that was used by the War Department beginning in 1942 for the production of trinitrotoluene (TNT). During the 1940's and 1950's, the Manhattan Engineer District and the Atomic Energy Commission brought various radioactive wastes and uranium processing byproducts (residues) resulting from our nation's atomic energy program to the LOOW for storage. Site operations caused soil, sediment, and groundwater contamination that lead to several remedial actions, which culminated in the construction of the Interim Waste Containment Structure (IWCS) on the NFSS. The U. S. Army Corps of Engineers (USACE)-Buffalo District is the lead Federal agency for Formerly Utilized Sites Remedial Action Program (FUSRAP) remediation of the NFSS. As the lead agency, USACE is conducting a remedial investigation/feasibility study (RI/FS) pursuant to the protocols set forth in the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). CERCLA activities at the NFSS have transitioned from the site RI activities to the FS evaluation of potential remediation alternatives. USACE recognizes the need to implement a focused CERCLA FS process and, therefore, has established three separate operable units (OUs) for NFSS: the IWCS OU, the Balance of Plant (BOP) OU [i.e., all on-site areas outside the boundary of the IWCS], and the Groundwater OU. This paper details recent investigations into the underground utilities, groundwater/soil contamination, and past storage of contaminated material on the Balance of Plant Operable Unit of the NFSS. Recent fieldwork activities have investigated areas of elevated groundwater contamination as well as an investigation to determine/eliminate any preferential pathway that historical underground utilities may have provided on-site in these areas. Additional areas of investigation included strategic placement of groundwater wells at locations of historic residue storage piles and intersections of various underground utilities (based on aerial photography and geophysical surveys). Several hundred locations across the site were investigated with a gamma walk-over survey, boring, surveying and sampling of soil-cores to aide in the delineation of soil contamination throughout the Balance of Plant Operable Unit. The series of investigations indicated multiple operational areas still have impacts above background conditions, risk-based concentrations, and promulgated maximum contaminant levels for multiple media in the Balance of Plant Operable Unit. The soil, groundwater, sediment, and utility sampling data show that 1) radionuclide impacts derived from ore-residue handling operations still exist, 2) impacts from other inorganic and organic compound exist in TNT manufacturing and support areas, and 3) contaminant transport from past source areas is minimal. The full compendium of site history and recent sampling data provides a well-defined conceptual site model that provides the necessary input data to prepare volumetric soil estimates for the Balance of Plant Operable Unit Feasibility Study. The scale of the NFSS and complexity of prior operations provide many remedial challenges. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

High-resolution Groundwater Investigation at a FUSRAP Site with an Aging Water-supply Infrastructure: Former Harshaw Chemical Company, Ohio - 16146

The Former Harshaw Chemical Company (HCC) Site is located in Cleveland, Ohio, approximately 5 kilometers (km) (3 miles) south of downtown Cleveland, in an industrialized area adjacent to the Cuyahoga River and Big Creek. Developed site parcels include former production areas with legacy buildings, former production area foundations, parking areas associated with previously demolished buildings, and re-developed privately-owned commercial properties. The HCC Site was initially developed 1905 and commercially manufactured chemical solvents, metal salts, fluorides, hydrofluoric acids, and other chemical products. HCC began production activities for the Manhattan Engineer District (MED) in late 1942 in support of the United States' early atomic weapons program. The primary process conducted by the HCC consisted of the refining of uranium oxide to produce several uranium-bearing materials, including uranium hexafluoride (UF{sub 6}), uranium tetrafluoride (UF{sub 4}), and uranium tetrachloride (UCl{sub 4}). The HCC also conducted numerous chemical and radiological research and production activities for the MED and later for the Atomic Energy Commission (AEC). Groundwater and soil contamination resulting from these activities is characterized in the site Remedial Investigation Report (USACE 2009) and primarily found near the G-1 process building. A Feasibility Study (USACE 2012) evaluated soil remediation alternatives and their potential impacts to future groundwater conditions. Since there is no groundwater pathway in the assumed industrial future land use, groundwater evaluations are intended to demonstrate that further degradation of groundwater will not occur after potential soil remediation. Total uranium is the primary MED-based groundwater contaminant and was numerically simulated using a site-specific groundwater flow and transport model. Remedial results are judged in terms of no significant impact, significant positive impact (i.e., significantly decreased extent of contamination), or significant negative impact (i.e., significantly increased extent of contamination). A complicating factor in the groundwater simulation and decision-making process for this site is the existence of municipal water-line leakage on and around the site. This aging infrastructure, in conjunction with the generations of modifications, promoted leakage and fresh-water contact with contaminated soils. To optimize the groundwater conceptual site model for numerical model updates, a high-density groundwater well network was installed in conjunction with the demolition of the G-1 building. The results of the detailed groundwater investigation, coincident soil sampling, utility-line termination, municipal water-line repairs, water-level collection, and uranium sampling indicates the groundwater is re-equilibrating and will lead to optimal decisions and site remediation. (authors)

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Change vs. Transformation, Hard Edges to Soft - The Role of Integrated Land Use Planning in the Adaptive Reuse of Contaminated Sites - 16431

Between the bookends of World War II and the Cold War, numerous cycles of up-sizing, down-sizing, and right sizing resulted in changing needs for federal real property to support government missions. The end of the Cold War has yielded many opportunities for reuse of federal facilities as defense-related property needs have been lessened. These federal facilities have both a historic and an environmental legacy, from radionuclides to unexploded ordnance to landfills and everything in between. Private-sector manufacturing sites have been especially affected by changing market demands. Obsolescence and advancing technologies have made the 'have to have it' product into the 'what was that for?' The result has been thousands of hectares (acres) of contaminated land throughout the country. While site histories go back in time, it is the environmental cleanup contaminants that have the ability to go forward in time and influence the future use of a site. Demonstrating that property conditions are protective of human health and the environment facilitates reuse options for these properties. Site reuse creates land for communities to attract businesses, grow their tax bases, add open space, and implement sustainability efforts, such as renewables, or set the property aside for future possibilities. A broad range of sites have been made available across the country as a result of federal mission changes and changed economic market conditions affecting private industry. This broad range of properties should have similarly broad recipes for reuse. Even with the constraints of zoning, topographic/natural conditions and use restrictions necessitated by past operations, the pathways to creative, adaptive, and sustainable reuse can be taken by integrating the planning with the remediation or, in a more community-sensitive approach, by integrating the remediation with the planning. Situations do exist where a like-kind use is an ideal reuse option, but a redevelopment of sameness need not be a foregone conclusion. Unlike the operational and imposed environments from which these sites came, with their engineered features often developed in a systematic manner with straight lines and hard edges, they can indeed be transformed into functional, relaxed, and engaging places and be productive again. A site's transformation can begin with how the remediation incorporates sustainable techniques that consider the future use of a site, and how the sustainable remediation can dovetail with the community's reuse plans. Rather than building on Greenfields and extending infrastructure and services to more distant locations, many communities are looking within their already developed footprints for growth possibilities. For some communities this is their only source of growth. Stigmatized and challenged as they may be to reuse, the nation's excess, under-utilized, surplus, and abandoned industrial past presents opportunities well worth considering for improvement to local and regional economies. Communities that are engaged in remediation and reuse planning efforts at these sites have the opportunity to shape their futures, transform their identities and incorporate sustainable practices throughout the process. Unlike the simple name change of a facility, transformative change takes time. Transformative change relies on working partnerships, dedication to achieving something better, open communication, and cooperative planning. It is this type of change that tends to be lasting and tailored to a place. (authors)

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