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This presentation, part of the JISEA 10th Annual (Virtual) Meeting, explores the next generation of low-carbon technologies for deployment on contaminated lands.
Low-carbon energy technologies and industries can reduce or avoid pollution, create economic development benefits (e.g. job creation), enhance local tax revenues, and support supply chain businesses. Many communities have vacant or underutilized and contaminated land that presents an opportunity cost for the economy and a blight on neighborhoods. This paper identifies a research agenda and funding proposal to support the next generation of low carbon technologies to deploy on contaminated lands.
The contamination legacy of industrialization, militarization, and nuclear arms race poses current or future risks to populations and the environment. Responsible parties and regulators make decisions regarding which sites to clean up, how, how much, and when. This study aimed to provide an information needs template to evaluate and reduce risks to human health when considering whether to initiate or delay remediation. This investigation focused on four aspects of timing and prioritization: 1) management, planning and implementation, 2) source terms, pathways, and exposures, 3) risks and receptors, and 4) external drivers. Within each type, issues were identified and described. Management class included personnel, health and safety data, funding, equipment, and structural integrity. Source term included contaminant sources, pathways, initiating events, and barriers to exposure. Risk included types and exposures to workers and general public. External drivers included regulatory framework, stakeholders, Congressional mandates, and economic and social contexts. Risk may increase over time as contamination spreads, enters aquifers, and reaches receptors, and may decline as radionuclides decay, and plumes dissipate. The overall objective was to provide a template of information that is useful to managers and regulators, and might be used by the public to understand the risks and benefits of re-prioritization cleanup.
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To optimise segregation at source, and hence minimise waste production, NUVIA have developed and utilised the Gamma Excavation Monitor (GEM) system. The GEM was designed for land remediation projects, to provide a rapid screening tool for excavator buckets of material. Following successful deployment in the UK, including the Olympic Park site in London, and two major Magnox land remediation projects, the first GEM unit was deployed to Canadian Nuclear Laboratories' (CNL) Chalk River Laboratory (CRL) in 2016. The GEM unit was fitted with a plastic scintillator detector; recent developments have included the utilisation of a sodium iodide. The system is initiated by the presence of an excavator bucket above the detector which triggers proximity switches that automatically start the counting routine. At the end of a short count time, typically 10 seconds, the materials category is indicated by means of a traffic light system, based on either the gross gamma activity or a photo-peak. Using this instrument, material determined not to be radioactive can be re-used on-site. In addition to the traffic light system, results are also transmitted wirelessly to a tablet device. These combined features allow operation of the system without the need to have operatives near the mechanical excavator bucket; therefore, eliminating a significant industrial hazard. Deployments of the GEM on the CRL site have included Storm Water Management project, within the CRL controlled area, and the Foundation Road Landfill Project. The use of the GEM in these projects enabled in-situ decisions to be made regarding the segregation and sentencing of soil rather than having to wait for the analysis of samples; saving time and cost to the project. The Building 492 project involved the excavation of soil within a supervised area to prepare for the installation of modular trailer units. For this specific job, the GEM was calibrated to ensure soil met clearance criteria as stipulated in the Nuclear Substances and Radiation Devices Regulations (Canadian Nuclear Safety Commission; SOR/2000-207). A total of 326 loads of soil were monitored during this project and re-assurance sampling conducted by CNL corroborated the results produced by the GEM system. (authors)
Rocket-powered vehicles utilizing Vertical Take-off Vertical Landing (VTVL) are a compelling alternative to surface rovers for exploring planetary and lunar bodies. These so called “hoppers” provide enhanced mobility for accessing locations difficult to reach, and over a wider region of the surface. However, contamination and plume interactions from rocket exhaust deposited at landing sites is anticipated since landing approaches are typically along a vertical direction during the final descent. Consequently, exhaust products may alter the surface chemistry, potentially confounding compositional analysis for samples collected in the vicinity of the landing site or jeopardize mining efforts. There has been no rigorous study on flight maneuvers that can mitigate plume-to-surface interactions. A multi-objective optimization tool has been developed to simulate propulsive hops on a planetary body and minimize both fuel consumption and site alterations. Trajectories are derived by multi-objective optimization and include solutions with significant reduction in contamination for a modest increase in fuel consumption. For these solutions, surface-to-surface propulsive transfer is demonstrated, but the method can also be modified for orbit-to-surface transfers (e.g., landers).
Rocket-powered vehicles utilizing Vertical Take-off Vertical Landing (VTVL) are a compelling alternative to surface rovers for exploring planetary and lunar bodies. These so called “hoppers” provide enhanced mobility for accessing locations difficult to reach, and over a wider region of the surface. However, contamination and plume interactions from rocket exhaust deposited at landing sites is anticipated since landing approaches are typically along a vertical direction during the final descent. Consequently, exhaust products may alter the surface chemistry, potentially confounding compositional analysis for samples collected in the vicinity of the landing site or jeopardize mining efforts. There has been no rigorous study on flight maneuvers that can mitigate plume-to-surface interactions. A multi-objective optimization tool has been developed to simulate propulsive hops on a planetary body and minimize both fuel consumption and site alterations. Trajectories are derived by multi-objective optimization and include solutions with significant reduction in contamination for a modest in-crease in fuel consumption. For these solutions, surface-to-surface propulsive transfer is demonstrated, but the method can also be modified for orbit-to-surface transfers (e.g., landers).
Tools have been developed to model and simulate the effects of lunar landing vehicles on the lunar environment (Metzger, 2011), mostly addressing the effects of regolith erosion by rocket plumes and the fate of the ejected lunar soil particles (Metzger, 2010). These tools are being applied at KSC to predict ejecta from the upcoming Google Lunar X-Prize Landers and how they may damage the historic Apollo landing sites. The emerging interest in lunar mining poses a threat of contamination to pristine craters at the lunar poles, which act as "cold traps" for water and may harbor other valuable minerals Crider and Vondrak (2002). The KSC Granular Mechanics and Regolith Operations Lab tools have been expanded to address the probability for contamination of these pristine "cold trap" craters.
Radiological risk assessments, in the form of performance or safety assessments, are often required under regulations or guidance for remediation of contaminated land, decommissioning of contaminated buildings or structures, and radioactive waste disposal. These risk assessments are usually supported by fate and transport models that address decay and ingrowth of radionuclides, as well as their movement through engineered systems and the natural environment. These models are often projected thousands, or more, years into the future, largely because the radioactive species change through decay and ingrowth, and hence the magnitude of the radioactive effect changes with time. There are many computer codes that are available to address this type of modeling. They range from addressing specific pathways or processes such as infiltration of water, groundwater, surface water, air, biota, diffusion and advection of water and gases, to those that try to couple all processes together to evaluate the impact of fate and transport through the entire system to places in space and time to which access is assumed. These different types of codes are sometimes separated with the monikers process-level and systems-level codes, although it is often not clear that this separation does justice to the capabilities of the many codes that are available to evaluate fate and transport of radionuclides. The focus of this paper is the latter group of modeling codes. Several systems level modeling codes exist and are used. There are differences between these codes in terms of utility, flexibility, complexity and cost. The purpose of this paper is to compare a few of these codes in the context of work currently being performed by the International Atomic Energy Agency (IAEA) Modeling and Data for Radiological Impact Assessments (MODARIA) II Working Group 1 (WG1). The MODARIA II WG1's main focus is how stakeholder engaged decision analysis can, or should, be applied to radiological contamination problems so that better, longstanding, sustainable, solutions are reached. However, the WG1 also recognizes the potential impact of the modeling tools that are chosen to address radiological risk, which is often a primary objective of decision making for radiological problems. Other objectives might also be important, such as constraining costs, obtaining financing, minimizing impact on ecosystems, saving cultural resources, saving jobs, farmland, environmental justice, etc., in a full decision analysis for a given radiological contamination problem, but none of these other objectives have the same types of complex modeling needs as minimize radiological dose. Consequently, a further focus of WG1 is to evaluate the potential impacts on decision making of the choice of fate and transport, and risk assessment, modeling codes that are used to support decision making. The WG1 will produce a report at the end of 2020 that will focus on an approach to effective decision making and stakeholder engagement. The report will also consider the role that performance assessment modeling should play in the decision-making process, including the impact of the choice of modeling tools or computer codes on risk-informed decision making. Several sites around the World have been made available by Member States for these model comparisons, and several modeling tools have been considered. However, the focus of this paper is on two of the sites, one in Belgium and one in Ukraine, and on three of the tools: NORMALYSA (NORM And Legacy Site Assessment); GoldSim{sup C}, and AMBER{sup C}. The final report from this working group will also cover other modeling tools, including RESRAD, and PC-Cream{sup R}. (authors)
Uranium (U) is a radionuclide of key environmental interest due its abundance by mass within radioactive waste and presence in contaminated land scenarios. Ubiquitously present iron (oxyhydr)oxide mineral phases, such as (nano)magnetite, have been identified as candidates for immobilisation of U via incorporation into the mineral structure. Studies of how biogeochemicalprocesses, such as sulfidation from the presence of sulfate-reducing bacteria, may affect iron (oxyhydr)oxides and impact radionuclide mobility are important in order to underpin geological disposal of radioactive waste and manage radioactively contaminated land. Here, this study utilised a highly controlled abiotic method for sulfidation of U(V) incorporated into nanomagnetite to determine the fate and speciation of U. Upon sulfidation, transient release of U into solution occurred (~8.6 % total U) for up to 3 days, despite the highly reducing conditions. As the system evolved, lepidocrocite was observed to form over a period of days to weeks. After 10 months, XAS and geochemical data showed all U was partitioned to the solid phase, as both nanoparticulate uraninite (U(IV)O2) and a percentage of retained U(V). Further EXAFS analysis showed incorporation of the residual U(V) fraction into an iron (oxyhydr)oxide mineral phase, likely nanomagnetite or lepidocrocite. Overall, these results provide new insights into the stability of U(V) incorporated iron (oxyhydr)oxides during sulfidation, confirming the longer term retention of U in the solid phase under complex, environmentally relevant conditions.
Ecological evaluation is essential for remediation, restoration, and future land-use decisions for contaminated lands, and forms a basis for many management practices. Ecological evaluations or assessments can also be used to examine the efficacy of remediation and restoration methods, providing valuable data to plan and improve future restoration. Assessments can examine past activities, current conditions, and the effects of future remediation or restoration. In general, ecological evaluations have not been used to assess the effects of delaying remediation. Yet for complicated situations, such as at Hanford Site, where there are dozens of remediation sites still to be completed, understanding the effects of delaying remediation on ecological and eco-cultural resources adds measurably to making sound sequencing decisions. Ecological evaluations are inherently complex compared to human health risk assessment because there are hundreds of species, composing a great number of communities and ecosystems. Ecosystems are dynamic, undergoing changes in response to predictable environmental conditions (succession), as well as unforeseen events. Further, ecosystems respond to remediation and restoration actions, even when they are on adjacent areas. Conducting evaluations of the risk to ecological resources must account for the dynamic nature of ecosystems, and for the dynamic, changing landscape that results from remediation on nearby areas. The approach will provide information for sound decision-making with stakeholder participation. This project was partially funded by CRESP through the Department of Energy (DE-FC01-95EW55084). (authors)
The Chalk River Laboratories (CRL) began nuclear operations in 1947. Portions of the site land areas have become radiologically contaminated through the 1952 National Reactor Experimental (NRX) accident and/or waste management activities over the past 70 years of site operations. The Environmental Remediation Projects Group (ERP) characterizes, and performs risk assessment, and remedial actions, as required over these contaminated land areas. ERP work activities are subject to controls established by CRL's Radiation Protection (RP) Group such that RP establishes the radiological controls and monitoring requirements for ERP field work activities. The different methods of monitoring soil contamination between ERP and the RP program present some challenges in the interpretation and comparison of the two sets of results and the soil disposition. ERP utilizes NaI(Tl) scintillation detectors and MARSSIM land scanning techniques to measure soil concentrations between sample locations and in excavated materials. Whereas, RP utilizes surface contamination monitoring equipment in the form of a 15.5 cm{sup 2} open area pancake Geiger-Mueller (GM) tube detector to measure soil contamination levels reported in counts per minute (cpm). This paper presents a method to evaluate the theoretical best responses that could be obtained from surface contamination monitoring instrumentation for a known concentration (1 Bq/g) of various radionuclides. A static efficiency of cpm/Bq{sup -1} g{sup -1} is obtained from these calculations. These contamination monitoring sensitivities are then used in a MARSSIM scanning sensitivity equation and compared to the scanning sensitivity of an NaI(Tl) scintillation detector. The results demonstrate that the sensitivity of the frisker probes to particle radiations (betas for pancake) tend to fall in a range of only a few cpm/Bq{sup -1} g{sup -1}. Rather, the primary static response of the pancake probe to soil contamination is from gamma radiation where a value of 36 cpm/Bq{sup -1} g{sup -1} for Cs-137 was obtained at 2.54 cm distance without the application of scanning statistics. In comparison, a 7.6 cm x 7.6 cm NaI(Tl) detector has a Cs-137 static response factor of 10,000 cpm/Bq{sup -1} g{sup -1} at 15 cm distance without applying scanning statistics. (authors)
: Wetlands have several important roles in the hydrological cycle, including maintaining water quality by removing surface and groundwater contaminants. Over time, the wetlands themselves can become contaminated, posing a secondary environmental threat. The objective of this study was to calculate the inventory of uranium (U) remaining in a wetland 50 years after the Fuel Fabrication Facility on the Savannah River Site located in South Carolina released 43.5 Mg of U into the nearby environment. Over 232 700 gamma spectra and their associated global positioning system (GPS) coordinates were collected and collated into a map of the contaminated land area. Five core samples were also collected that contained U concentrations as high as 14 099 mg/kg (background levels are about 2.7 mg/kg U). The contaminated area was 278 000 m2 , and it contained 36.2 Mg U, about 83% of the U released. About 80% of the U in the wetland was concentrated in a former beaver pond, a 73 000 m2 area (26% of the contaminated area). This contaminated wetland area was almost 2 km from the source, indicating that it comprised unique hydro-biogeochemical properties for immobilizing the released U. To the best of our knowledge, this is the first data-rich study to quantify the long-term effectiveness of a wetland to immobilize inorganic contaminants. Significant environmental changes to the system, such as those associated with hydrology, forest fires, or anthropogenic land use, may alter the complex hydro-biogeochemical interactions necessary for the long-term immobilization of the U.
The Government of Canada's nuclear legacy liabilities have resulted from ∼70 years of nuclear research and development (R and D). The majority of these liabilities are located at the CRL Site and consist of shutdown research buildings (including prototype and research reactors), plus a wide variety of buried and stored wastes, and contaminated lands. The Environmental Remediation Projects (ERP) branch are assessing the waste inventory in the Chalk River Laboratories Waste Management Areas in order to make informed and risk based decisions on remediating affected lands. This paper provides examples of contaminated sites at CRL that require remediation as well as examples of remediation activities already complete. The environmental remediation process followed at CRL and the development of the CRL site cleanup plan are outlined. Until suitable disposal facilities are available ERP will continue to characterize and assess contaminated sites, monitoring and managing the risks in place while preparing for full-scale remediation activities. (authors)
Surveyor 5 landing site contamination from solid aluminum oxide particles in main retro exhaust