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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Decommissioning, Decontamination, and Disposal of LLW-LL, and ILW-LL at a Former Rare Earths Processing Facility in Malaysia - 19087

Geosyntec Consultants, Inc. (Geosyntec) was the design-build Contractor for a project involving the remediation and disposal of low level (LLW-LL and ILW-LL) NORM and TENORM wastes at a former rare earth processing facility in Malaysia. These sites were associated with a plant that extracted rare earth elements from local tin ores. Because of the naturally occurring radioactivity contained in the raw materials, these productions resulted in by-products and residues containing LLW-LL and ILW-LL thorium hydroxide and uranium hydroxide. The total mass of uranium (∼120 tons) and thorium (∼1,200 tons) managed in a single repository required the project design incorporate requirements related to inventory, security and safeguards around nuclear precursor materials. The requirement to consider a performance over a period of more than 10,000 years led to significant challenges in design and modeling of the disposal facility as this disposal facility was purposely designed and permitted as a final disposal for the LLW-LL and ILW-LL. The first phase of the project was the decommissioning, decontamination, and demolition of the 14- acre former rare earth processing plant and excavation of contaminated soils, construction of an engineered cell at the repository for waste disposal, and transportation and disposal of the waste materials into the cell. Final status surveys were carried out to allow the site to be successfully released by the Malaysian regulatory authorities as a clean site for re-development as common industrial use. Over 11,000 loads of material, including approximately 75,000 cubic meters of excavated soils and plant debris, were transported in specially designed steel transport boxes on public roads for disposal in the engineered cell. The second phase of the project included the design and construction of a second engineered cell, enhanced with protective barrier systems and a final cover system constructed of natural materials. Ancillary facilities such as substations, offices, processing buildings, and wastewater treatment plants were constructed to support retrieval and processing of the materials from more than 87,000 individual drums using a semi-automated process. The drums, waste packages, and other materials in the storage facility were systematically extracted, sorted, inventoried, solidified using Portland cement, transported, and disposed in the cell. All temporary facilities were decontaminated, demolished, and disposed in the cell. Radiological inventory and radiation safety programs were implemented to quantify the waste activity and to control exposure to workers and the public during the project. The total mass of radioactive contaminated waste disposed in the two projects is nearly 200,000 tons. The projects were carried out under a high level of scrutiny from Malaysian and international regulatory bodies. Between 2014 and 2017, performance monitoring and modeling activities were carried out to demonstrate that the disposal facility was performing in accordance with design requirements established by regulatory agencies. (authors)

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

A review of the behavior of radioiodine in the subsurface at two DOE sites

The 129 I isotope has a half-life of nearly 16 million years, creating a potential risk to receptors when 129I is present in groundwater and effective remedies are needed to mitigate its potential risk in the environment. This paper not only provides an in-depth review of various processes and reactions that control the fate and transport of iodine, but also describes how this information can be used for in situ management of iodine. The majority of the iodine fate and transport studies have been conducted at the US Department of Energy (DOE) Hanford and Savannah River sites, where radioisotopes of iodine were inadvertently released into the environment during weapons production. Site-specific remediation technologies are currently being evaluated as part of the DOE cleanup mission. The sites are markedly different in terms of climate (arid vs. sub-tropical), major geochemical parameters (pH ~ 7.5 vs. 4) and mineralogy (carbonate vs. Fe/Al oxide dominated), but they share the same network of processes and reactions that control iodine fate and transport. These include adsorption to minerals and sediments, interactions with organic matter, electron transfer reactions with minerals and microbes, and precipitation. In conclusion, this process-based network serves as basis for regional scale model calculations to predict plume spreading and/or dissipation, design efficient remediation techniques and conduct contamination management activities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Startup of the New 200 West Pump-and-Treat, Hanford Site, Richland, Washington - 13214

On June 28, 2012, CH2M HILL Plateau Remediation Company (CHPRC) completed the construction and acceptance testing for a new 2,500 gallon-per-minute (gpm) pump-and-treat (P and T) system in the 200 West Area of the Hanford Site in Washington State. This system is designed to remove Tc-99, carbon tetrachloride, trichloroethene (TCE), nitrate, and total and hexavalent chromium from groundwater using ion exchange, anoxic and aerobic bioreactors, and air stripping. The system will eventually remove uranium from groundwater using ion exchange as well. The startup of the P and T system is important because it will ensure that contaminants from the 200 West Area never reach the Columbia River. When fully operational, the 200 West P and T will include approximately 23 extraction wells and 21 injection wells. The extraction wells are 8 inches in diameter, are completed with well screens 100 feet or more in length, and are distributed throughout the central portion of the 5-square-mile carbon tetrachloride plume. The injection wells are also 8 inches in diameter and are installed up-gradient of the plumes to recharge the aquifer and down-gradient of the plumes for flow-path control. Groundwater in the 200 West Area is approximately 250 feet below ground surface, and the aquifer is 200 feet or more in thickness. All of the contaminants (except nitrate) are found within the perimeter of the carbon tetrachloride plume and occur at various depths throughout the aquifer. The 200 West P and T consists of two separate buildings to conduct groundwater treatment. The RAD building contains an ion exchange system to remove Tc-99 from groundwater at a maximum flow rate of 600 gpm. The RAD building only accepts water from those extraction wells showing elevated Tc-99 concentrations. Groundwater initially fills an influent tank, is then pumped through particulate filters (to remove suspended materials), and then passes through two parallel treatment trains containing Purolite{sup R} A530E resin (which has been proven effective in removing Tc-99). The water is then transferred to the biological treatment building for further treatment. When the lead vessel in each of the two treatment trains becomes fully loaded with Tc-99, the Purolite A530E resin is transferred to a separate tank where it is heated to 160 deg. F to remove volatile organics prior to disposal at the Environmental Restoration Disposal Facility. The biological treatment building has a maximum flow capacity of 2,500 gpm. Groundwater from the nonradiological extraction wells and treated groundwater from the RAD building are initially pumped into an equalization tank and then into two parallel fluidized bed reactors (FBRs). The FBRs contain granulated activated carbon in suspension for microbes to populate, a carbon-based food source for the microbes to eat (e.g., MicroCg{sup TM}, molasses, or sodium lactate), and nitrate for the microbes to breathe (represents 'anoxic' conditions that contain little or no dissolved oxygen). The FBRs are maintained at a temperature between 55 deg. F and 90 deg. F, and at a pH between 6.5 and 6.8, to maximize microbial growth. The FBRs break down the nitrate, reduce the hexavalent chromium to trivalent chromium, and break down a good portion of the carbon tetrachloride and TCE. From the FBRs, groundwater is pumped through a carbon separation tank, then through a splitter box that divides the water evenly between four membrane bioreactors (MBRs) that further break down the contaminants. The MBRs have aeration capacity to provide sufficient oxygen for maintaining the aerobic biological process. The MBRs use submerged membranes for filtration. Vertically strung fibers are found in the membrane zone where a vacuum draws water through tiny pores in the fibers. The liquid is then pumped to air strippers to remove any volatile organics that have passed through the bioreactors. Solids from the MBRs are pumped to rotary drum thickeners and centrifuges for dewatering prior to lime being added to kill the bacteria and control odor. The conditioned sludge is then disposed at the Environmental Restoration Disposal Facility. The final treated water is then pumped to the injection well field. The 200 West P and T is a Leadership in Energy and Environmental Design (LEED) gold-certified facility that has an expected 70% energy cost savings over the lifetime of the plant. Fifty percent of the steel used in construction was recycled, 420 tons of recycled concrete were used, and over 75% of construction waste was diverted from landfills. The plant is only staffed one shift per day, and it uses a call-out system if the plant goes down during off-shift hours. Initial sampling results have shown that the 200 West P and T is successfully reducing contaminant levels well below the cleanup levels specified in the Record of Decision, Hanford 200 Area 200-ZP-1 Superfund Site, Benton County, Washington [1]. CHPRC and the U.S. Department of Energy are continuing to look for ways to reduce operational costs, such as testing alternative resins for removing radionuclides and finding less expensive carbon substrate sources. The benefit to others is a LEED gold-certified, 2,500 gpm P and T system that may be used as a model for other complex sites. (authors)

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

Testing and Deployment of Remote Systems to Remove Highly Radioactive Soil at Hanford's 324 Building - 18043

U.S. Department of Energy (DOE) contractor CH2M HILL Plateau Remediation Company (CHPRC) is in the process of procuring, testing and deploying remotely operated tools to safely remove highly contaminated soil from beneath the 324 Building on the Hanford Site in southeastern Washington State. The 324 Building operated for more than 40 years, completing a variety of high-dose engineering development and demonstration activities inside six hot cells that shielded the workers from the highly radioactive materials. Activities to decommission, decontaminate and demolish the facility began in 2008. In 2010, soil contamination was found in the soil under one of the hot cells, and building deactivation was paused to evaluate the soil contamination. Sampling efforts, using borehole technology, revealed significant under-building contamination with dose rates measuring has high as 130 Sv/hr (13,000 R/hr). The highly-contaminated soil has to be removed before traditional open air deactivation activities can continue. CHPRC completed proof of concept testing and built a full-scale test facility to demonstrate the effectiveness of three primary tools that will accomplish the floor and soil removal. The tools include a commercially available concrete saw, and a commercially available excavator arm that have been modified to operate remotely in the high-radiation environment within the hot-cell. In order to reduce the wear on the hot-cell overhead cranes, a remote operated rail and cart system has been designed to transport soil and debris out of the hot-cell to an airlock area where the waste will be separated, according to its level of radioactivity. A camera and light system has been designed to provide visual and audio coverage of the hot-cell area that will allow the operations to proceed from remote control stations. This paper will describe the primary remote operated equipment designed for the project and the challenges and processes for developing, testing and deploying the equipment necessary to excavate the soil from below the 324 Building. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Conservation of Helium while Maintaining High System Purity

Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful sel ection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Conservation of Helium while Maintaining High System Purity

Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful selection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Demolition of the K-27 Building at the East Tennessee Technology Park (ETTP) - 17423

On February 8, 2016, URS - CH2M Oak Ridge LLC (UCOR) initiated the demolition of the East Tennessee Technology Park's (ETTP's) final gaseous diffusion building in DOE's Oak Ridge Environmental Management program. Building K-27 was a 35,582 m{sup 2} (383,000 ft{sup 2}) gaseous diffusion building that contained approximately 92,903 m{sup 2} (1 million ft{sup 2}) of floor space. It was one of five gaseous diffusion buildings at the site, formerly known as the Oak Ridge Gaseous Diffusion Plant. The actual demolition of this facility took approximately seven months to complete; however, planning and preparation took more than three years. The deactivation process was a critical element in preparing the building for demolition. UCOR's K-27 deactivation activities began in April 2012 with the installation of safe walking paths and fall protection systems to allow safe work access. Next, all mechanical and electrical systems associated with the facility were shut down and isolated, a process known as 'cold and dark.' More than 19.3 km (12 mi) of process piping and components were marked and measured. Additionally, workers performed nondestructive assay (NDA) and vent-purge-and-drain activities and applied foam to piping and components as needed [1]. Based on characterization results, approximately 4.8 km (3 mi) of process piping, and 372 converters and compressors were removed and shipped offsite prior to demolition. Lower-hazard materials and equipment were demolished with the building structure and transported to onsite disposal facilities. Upfront waste characterization and ongoing monitoring were key to the successful disposal of demolition debris at onsite facilities. Due to process improvements in waste loading recommended by work crews, the project achieved a 50 percent improvement in the daily hauling rate during the 9,000-truckload shipping campaign. Crews worked in high-risk, high-hazard conditions and were exposed to radiological and chemical contaminants, extreme temperatures, and deteriorating infrastructure. However, the hazard controls that were put in place, based on the Integrated Safety Management System (ISMS) walk-downs and hazard determination, made the effort manageable. The overall safety performance during demolition of the facility was excellent, with no significant injuries, and exceeded industry standards and DOE target levels. Outstanding safety performance was a testament to the dedication of the workforce, given the significant hazards presented by the demolition of the Hazard Category 2 nuclear facility. Another key element to the success of the K-27 demolition was the support and approval of all stakeholders involved in this effort, including DOE, the surrounding communities, the State of Tennessee, the UCOR management team, and, most importantly, the workforce that performed this highly hazardous work. This $52 million demolition project was completed ahead of schedule with no significant injuries and in compliance with all DOE orders, site procedures, and environmental controls. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Next Generation Logistics Systems for Delivering Optimal Biomass Feedstocks to Biorefining Industries in the Southeastern U.S.

The diverse portfolio of biomass sources that is available in the Southeastern U.S., including a significant supply of pine “residue”, represents a valuable strategic position for the region. Through blends formulated based on critical properties, this project will take full advantage of the range in biomass properties afforded by the portfolio to produce a consistent, high-performance feedstock for the industry, while lowering cost. Key developments being targeted to enable this potential include whole-tree transport to a state-of-the-art merchandising depot that will further access biomass from ongoing, forest industry operations. The approach will more effectively utilize the tree and distribute cost, while minimizing in-woods contamination of the woody biomass component. To implement this vision, information on the chemical composition and changes that are induced during multiple preprocessing steps (size reduction, moisture removal, densification, etc.) is needed. New NIR sensor technology will be developed for online monitoring of important biomass properties. The data will be incorporated into a statistical process control platform to improve process efficiency and meet required specifications. Advanced process models are being developed to inform the techno-economic and life-cycle assessment of the program’s impact. The new system will ultimately reduce operational risks from supply chain disruptions, and allow operation of larger-scale biorefineries.

09 BIOMASS FUELS↗
DOE OSTI2015

Post-closure program streamlining at the Nevada national security site - 15290

More than 200 sites on the Nevada National Security Site (NNSS), Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR) have been closed in place. At these sites, contamination has been left in place, and protection of human health, safety, and the environment is ensured through the establishment of use restrictions (URs). Post-closure requirements were initially established in the Closure Report (CR) for each site and include a variety of inspection, monitoring, maintenance, and reporting commitments. Post-closure requirements and site controls (fences, monuments, soil covers, and postings) may vary depending on site location, accessibility, land use scenario, and the nature of contaminants left in place. Corrective Action Sites (CASs) on the NNSS, NTTR, and TTR have been identified for closure under the Federal Facility Agreement and Consent Order (FFACO), which was signed in 1996. Over 1,900 CASs have been closed under the framework of the FFACO, and more than 200 of those have URs. Many post-closure requirements have been modified over time. In addition, because the scope of the program has spanned almost 20 years, the post-closure requirements have varied due to changing strategies and expectations. Because of the number of sites closed over the course of the program, post-closure requirements are found in hundreds of closure documents, addendums, errata sheets, Records of Technical Change, inspection reports, permit modifications, and correspondence. Furthermore, resources such as personnel and funding necessary to conduct the post-closure program have diminished, while computer capabilities and configuration control principles have improved since closure activities under the FFACO began. Because of these factors, to effectively manage the post-closure program, ensure that all commitments are being met, and improve the ease of identifying the most current post-closure requirements for each UR, the current requirements for every use-restricted site under the purview of the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office will be consolidated into a single Post-Closure Plan. The Consolidated Post-Closure Plan will also outline a strategy and present possible criteria that may be used for future evaluation of post-closure requirements. Continual assessment of the post-closure program will ensure that the post-closure requirements for URs across the NNSS, NTTR, and TTR are consistently justifiable and sufficient to protect site workers, the public, and the environment while increasing efficiency. Future changes to post-closure requirements and justification for those changes will be recorded in revisions to the Consolidated Post-Closure Plan. This process will provide a comprehensive, consistent, and streamlined method for evaluation of post-closure requirements and implementation of changes. (authors)

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Achieving groundwater monitoring optimization at SRS: a core team process based on rigorous technical assessment - 15273

The optimization of groundwater monitoring at Savannah River Site (SRS) was achieved through a core team process based on the application of a comprehensive, technical evaluation of individual regulated groundwater units. Groundwater monitoring at SRS is required at dozens of waste sites and includes about 4,000 samples annually. The expected longevity of groundwater contamination and associated groundwater monitoring and reporting constitutes a significant long-term cost to the environmental management budget. The core team, consisting of representatives from the Department of Energy (DOE); U.S. Environmental Protection Agency (USEPA); and the South Carolina Department of Health and Environmental Control (SCDHEC), recognized that monitoring needs for individual plumes evolve as remediation work progresses. The technical evaluation plan was generally based on the availability of many years of monitoring data. In addition, it was recognized that the well network, sampling frequency, and analytical suite had been the same for years and warranted evaluation to determine if the existing monitoring was meeting the current objectives. In order to systematically evaluate monitoring at eighteen different groundwater units, SRS developed a decision-logic analysis using flow sheets to address five areas of optimization identified with core team agreement, including: (1) current monitoring vs regulatory requirements, (2) spatial optimization, (3) temporal assessment, (4) analyte assessment, and (5) reporting assessment. The evaluation resulted in SRS proposing changes in the spatial, temporal, analyte, and reporting aspects of groundwater monitoring for fifteen of the eighteen individual groundwater units evaluated. Overall, these changes have resulted in annual savings of $370 K to date, with an additional $200 K in annual savings pending. Early and frequent core team deliberations helped ensure the success of this optimization effort. The technical evaluation was conducted after receiving core team buy-in for the goals and methods of the project. Technical evaluations for each unit were proposed to the regulators in unit-specific regulatory submittals. The technical justifications and core team decisions were all documented and implemented in accordance within the framework of the SRS Federal Facility Agreement or Resource Conservation and Recovery Act (RCRA) Permit process. This optimization approach can be expected to be highly successful for sites with rich historical data sets and where the requirements in regulatory monitoring plans can be negotiated. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Uranium sorption to organic matter and long-term accumulation in a pristine alpine wetland

Understanding the controls on uranium (U) mobility in the environment is key to improve the management of sites contaminated by U mining activities. Previous research has shown that natural or engineered wetlands are particularly able to scavenge high amounts of U(VI) and U(IV) under noncrystalline forms. However, questions remain on the respective roles of sorption and reduction processes in the removal of U from running waters in wetlands, as well as on the long-term stability of U storage. Here, we performed a series of geochemical, isotopic ($δ$ 238 U, ( 234 U/ 238 U)), microscopic (SEM-EDXS, EPMA) and spectroscopic (µ-XRF, µ-XAS, XANES and EXAFS at the U L 3 and M 4 -edges and Fe K-edge) investigations to determine the modes of U accumulation and assess U mobility in a natural exceptionally U-enriched (up to 5000 µg/g) wetland on the shore of Lake Nègre (Mediterranean Alps, France). Uranium (VI) was largely dominant in the two studied soil cores, except a few samples containing as much as ~50 % U(IV). At the particle scale, U is associated to a variety of organic constituents of the soil matrix with a homogenous oxidation state. Bulk EXAFS spectroscopy at the U L 3 -edge shows that U is mostly mononuclear, with dominant monodentate binding to organic moieties (C neighbors at ~3.45 Å). An additional minor fraction of U under polymeric forms is inferred from wavelet (CCWT) analysis of the EXAFS data. These observations are reinforced by 1 M bicarbonate extractions that result in the dissolution of 82–96 % of total U, including putative polymeric species. At the wetland scale, similar or slightly fractionated isotopic ratios ($δ$ 238 U) between the wetland-feeding creek waters and the wetland soils are observed, supporting the idea that U(VI) sorption on organic matter is the primary U scavenging mechanism. Furthermore, it indicates that partial U(VI) reduction to U(IV) occurs as a second step, after sorption. Analysis of U decay chain disequilibria in the cores as a function of depth suggests that U accumulation in this wetland has lasted for several thousand years. In conclusion, we propose that the wetland acts as an active reactor where U has been massively accumulating for ~14500 years, especially as U(VI) forms associated to organic matter and is further partly exported to the lake through soil erosion.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2025

Manganese in drinking-water reservoirs: a multi-disciplinary review of current issues, biogeochemical controls, and oxygenation-based management

Decreased water quality and increased treatment costs due to excess manganese (Mn) in drinking-water supplies are critical issues globally. To combat on-going and emerging taste and odour issues with Mn and other contaminants (e.g., algal toxins), many utilities are using engineered oxygenation or aeration (EOA) systems to improve water quality in lakes and reservoirs. Resultant shifts in key biogeochemical and physical processes are still poorly understood, often leading to inefficiently managed systems. Paired with knowledge gaps regarding environmental drivers of Mn and the complexity of Mn redox kinetics, Mn problems persist. This review presents the state of current research in areas critical to optimisation of EOA mitigation of Mn, with focus on i) Mn biogeochemical cycling within drinking-water reservoirs; ii) influences of local catchment geology, hydrology, and land use on Mn dynamics; and iii) Mn management using different EOA approaches. The importance of considering the combined implications of these factors for successful Mn management in reservoirs is highlighted by an evaluation of relevant field-based studies; a wide range in EOA performance is observed, from a 97 % decrease in soluble Mn up to a ∼400 % increase in total Mn. Despite the breadth of studies that consider Mn in water-supply systems, there are still several areas of research which warrant further investigation, including: the influence of natural sources and anthropogenic activities on Mn within a given catchment, Mn speciation and transport in stratified and destratified lakes and reservoirs, and optimal site-specific EOA strategies for Mn mitigation.

Aeration↗
DOE OSTI2017

Reliable SOFC Systems

The goal of this U.S. Department of Energy (DOE) sponsored project was to advance the reliability, robustness and endurance of low-cost SOFC technology suitable for ultimate deployment in ≥100 MWe Integrated Gasification Fuel Cell (IGFC) or Natural Gas Fuel Cell (NGFC) systems capable of ≥97% CO2 capture. The ultimate SOFC program goals are ≤ 0.2% per 1000 hours power degradation over a 5-plus year stack life, high-volume (≥ 250 MW/year) stack production cost of ≤$225/kWsystem net AC, and “power block” (exclusive of fuel supply, contaminant removal, and CO2 capture subsystems) capital cost of ≤ 900/kWsystem net AC (in year 2011). To progress towards the ultimate program goals, the specific objectives of this project were to achieve an SOFC stack power degradation rate of ≤1.5% per 1000 hours in a 100 kW (125 kW Peak) Modular Power Block (MPB) stand-alone power system under thermally self-sustained normal operating conditions and to verify the prospects for high volume SOFC stack production cost below the DOE target of ≤ 225/kW. This final technical report summarizes the progress made during the project period of 36 months. Significant progress was made in the areas of cell and stack technology development, Modular Power Block (MPB) development, sub-MW MPB system development, and MW-class SOFC System Development and Costing. The work focused on areas necessary for comprehensive development of an SOFC fuel cell system, including, active cell improvement, contaminant resistance, process engineering, and development of non-repeat module components. Additionally, several custom built balance-of-plant components were designed and fabricated to support the fuel cell system. SOFC cell and stack development focused on improving cell performance and durability. Enhancements were achieved in areas of electrode stability and impurity tolerance. Additionally, several quality control techniques and tools were developed to ensure predictable and repeatable fabrication of SOFC stacks. Module development continued previous development efforts to achieve footprint reduction and higher efficiency by incorporating balance-of-plant functional equipment into the fuel cell containment module. Several improvements were made to prior design. Control and instrumentation hardware was integrated within the module for serviceability and size reduction. The design efforts culminated in a complete SOFC power plant system. The designed plant was constructed and tested at FCE. Stack and system costs were updated, reflecting advances made in this program.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2016

WOW Technology's Innovative Radioactive Liquid Waste Treatment - 16128

WOW presents its revolutionary technology and equipment for liquid radioactive waste treatment: outperforming ultimate water decontamination and purification process, enhanced sludge concentration, no secondary waste nor consumables, fully automated, remote controlled and self-decontaminating device. The WOW's technology is based upon a never before observed discovery of fluid dynamics science: the possibility of performing a molecular separation between solute and suspended elements and the solvent. The combination of such a molecular separation process with a standard vacuum evaporation improves the abatement performances by thousands of times, with respect to those of the state of the art vacuum evaporators. In addition to this, no secondary waste is produced during the process, as no filters, membranes, resins or additives are used. WOW equipment, automated and remote controlled, self decontaminates after use and can be designed and constructed either tailored to the application needs or with a modular approach for enhanced transportability and application flexibility. After the preliminary verification by CNR, the Italian National Research Center, WOW Technology's decontamination device was tested c/o LENA, the Laboratory of Applied Nuclear Energy of the University of Pavia, Italy with a simulated solution 6000 times more contaminated than the nuclear reactor's cooling water of Fukushima-Daiichi NPP. In addition to that, WOW's technology was also used in a real case at the Radiochemistry laboratory of the Pavia's University Chemistry department. Both the above mentioned contaminated fluids have been successfully decontaminated without production of additional or secondary waste. WOW's technology has already performed on industrial scale c/o the Nuclear Repository of S.S.M. in Saluggia, Italy: 45000 liters of acid radioactive solution have been successfully decontaminated to a Decontamination Factor (DF) of 335000 for Cs-137 by one single evaporation step and without using any additional tool to control steam. [Performances independently certified by: National Physics Laboratory (UK) and Pavia University Radiochemistry Laboratory, Chemistry Department (Italy)]. The high decontamination factors and the high volume reduction of the sludge make this technology suitable for the ultimate treatment of highly contaminated liquid waste such as the Fukushima-Daiichi nuclear reactor's cooling water. The WOW's technology addresses as well to interventions in both, operating and decommissioning nuclear power plants and any other nuclear and radioactive facility whose produced and/or stored radioactive liquid solutions, including acid liquid solutions, can be successfully treated, the waste volume reduced and no secondary waste produced. (authors)

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

Implementation and evaluation of a radiological field investigation for real property interests associated with the FUSRAP Maywood Site - 15611

Public streets, easements, and rights-of-way, collectively referred to as Real Property Interests (RPI), pose challenging and complex problems for the FUSRAP Maywood Project Team. RPIs are components of a multi-faceted objective to evaluate all remaining sources of contamination for which the Government is responsible under the Maywood Record of Decision. USACE designed and implemented a MARSSIM-based radiological investigation within sixteen potentially impacted RPIs. These RPIs were not completely addressed on their own or in conjunction with nearby property investigations or remediations. However, these RPIs were investigated based on the potential for or known impact of FMSS contamination as determined through both a historic data review of the transport mechanism (downstream waste deposition) and process knowledge obtained during Final Status Survey of proximal properties. The primary objectives of this investigation were to confirm the presence or absence of FUSRAP contamination within a given RPI, provide sufficient data to release an RPI if contamination was not encountered, and provide sufficient data for either design of an appropriate remedial solution or implementation of Land Use Controls when contamination was encountered. Of additional value, knowledge gained during the RPI investigations will allow the team to share useful radiological data with local officials and utility service providers. This information will support better, more informed decisions by all parties involved in situations such as emergency subsurface utility repairs, roadway improvement planning, or even natural disaster response. Finally, certain unexpected outcomes learned during the final data analysis may lead to refinement of the conceptual site model. Logistical lessons learned and challenges encountered during the Maywood investigation may also be helpful to stakeholders, planners, and managers of similar projects wishing to identify their own potential liability within public streets, easements, rights-of-way, and other types of RPIs. (authors)

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

Technology for Treatment of Liquid Radioactive Waste Generated during Uranium and Plutonium Chemical and Metallurgical Manufacturing in FSUE PO Mayak - 13616

Created technological scheme for treatment of liquid radioactive waste generated while uranium and plutonium chemical and metallurgical manufacturing consists of: - Liquid radioactive waste (LRW) purification from radionuclides and its transfer into category of manufacturing waste; - Concentration of suspensions containing alpha-nuclides and their further conversion to safe dry state (calcinate) and moving to long controlled storage. The following technologies are implemented in LRW treatment complex: - Settling and filtering technology for treatment of liquid intermediate-level waste (ILW) with volume about 1500m{sup 3}/year and alpha-activity from 10{sup 6} to 10{sup 8} Bq/dm{sup 3} - Membrane and sorption technology for processing of low-level waste (LLW) of radioactive drain waters with volume about 150 000 m{sup 3}/year and alpha-activity from 10{sup 3} to 10{sup 4} Bq/dm{sup 3}. Settling and filtering technology includes two stages of ILW immobilization accompanied with primary settling of radionuclides on transition metal hydroxides with the following flushing and drying of the pulp generated; secondary deep after settling of radionuclides on transition metal hydroxides with the following solid phase concentration by the method of tangential flow ultrafiltration. Besides, the installation capacity on permeate is not less than 3 m{sup 3}/h. Concentrates generated are sent to calcination on microwave drying (MW drying) unit. Membrane and sorption technology includes processing of averaged sewage flux by the method of tangential flow ultrafiltration with total capacity of installations on permeate not less than 18 m{sup 3}/h and sorption extraction of uranium from permeate on anionite. According to radionuclide contamination level purified solution refers to general industrial waste. Concentrates generated during suspension filtering are evaporated in rotary film evaporator (RFE) in order to remove excess water, thereafter they are dried on infrared heating facility. Solid concentrate produced is sent for long controlled storage. Complex of the procedures carried out makes it possible to solve problems on treatment of LRW generated while uranium and plutonium chemical and metallurgical manufacturing in Federal State Unitary Enterprise (FSUE) Mayak and cease its discharge into open water reservoirs. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Scale-dependent spatial variabilities of hydrological exchange flows and transit time in a large regulated river

Hydrological exchange flows (HEF) across the river-aquifer interface and the associated residence time of river water in the aquifer have important implications for contaminant plume migration and biogeochemical processes in the river corridor. HEFs and residence time are influenced by both subsurface physical features and hydrologic forcing related to the transport process, which can exhibit complex spatial and temporal variations. In this study, we used a massively parallel subsurface flow model and a particle-tracking model to study the influences of different control factors on spatial variability of HEFs and residence time distributions (RTD) in the Hanford Reach of the Columbia River in Washington State. A total number of 100M particles were randomly injected in time and space and then tracked in a model domain that covers a 51-km 2 area (15.1M model cells). We used hourly river stages and groundwater levels to drive the model to provide dynamic velocity fields for the particle tracking in the simulation period that was longer than 2 years. The groundwater flow simulation and particle-tracking results provide the first comprehensive assessment of the spatial distribution of HEFs and residence time in large complex river corridors. Overall, our results show that the aquifer hydrogeological structure has the strongest correlation with the extent and magnitude of exchange flux. The residence time exhibits complex patterns that are impacted by all the river geomorphologic, hydrodynamic, and hydrogeologic factors and are strongly correlated with the downwelling ratio of exchange flux. The new insights gained through this study can be used to support the development of reduced-order models of HEFs and RTDs for large complex river systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Literature Review of Documented Persistent Secondary Uranium Sources at DOE LM Sites

The U.S. Department of Energy Office of Legacy Management (LM) has the responsibility to protect human health and the environment at 101 legacy uranium sites across the nation by implementing long-term surveillance and maintenance requirements. Included in these responsibilities is to provide for the safe and environmentally sound disposal, long-term stabilization, and control of uranium mill tailings in a manner that minimizes or eliminates radiation health hazards to the public at 21 Uranium Mill Tailings Radiation Control Act (UMTRCA) Title I sites; 6 UMTRCA Title II sites; and 9 Comprehensive Environmental Response, Compensation, and Liability Act/Resource Conservation and Recovery Act sites. These sites are former uranium mills (processing sites), or sites with wastes from processing sites encapsulated in engineered disposal cells (disposal sites), or sites where components of atomic weapons were manufactured. During site characterization, groundwater contamination was often discovered and evaluated or modeled for future movement with the inclusion of uranium sorption in the groundwater plume. Much of this original work did identify uranium processing wastes as the original contaminant source. However, more recent work has identified the existence and influence of persistent secondary uranium sources that may prevent uranium in groundwater from attenuating as quickly as initial evaluations or modeling indicated. By understanding these processes, better decisions can be made to choose the appropriate remediation and closure strategies, identify long-term surveillance and maintenance activities, and more accurately estimate life-cycle costs. The purpose of this report is to summarize the literature available on documented persistence secondary uranium sources at LM sites as part of the Applied Studies and Technology Persistent Secondary Contaminant Sources Project.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗