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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Collaborative Research Programme in Decommissioning, Immobilisation and Storage Solutions for Nuclear Waste Inventories (DISTINCTIVE) - 16466

The UK government remains committed to nuclear power as an important part of the energy generation capacity over the next 30-50 years and possibly beyond, with aspirations for both new-build power stations and lifetime extension of the existing fleet. A central component of public acceptance for any new-build programme is the need to demonstrate our ability to safely manage and dispose of high- and intermediate-level wastes from legacy nuclear operations. Clear milestones associated with the needs of waste management and decommissioning have been provided by the UK government, and most rely on further research and technical developments being delivered over the next 10-20 years. The DISTINCTIVE (Decommissioning, Immobilisation and Storage Solutions for Nuclear Waste Inventories) consortium is carrying out research that addresses the broad area of nuclear waste and decommissioning, bringing together key industry partners and leading academic researchers from 10 of the UK's leading research intensive universities. The research being carried out is multi-disciplinary and covers both fundamental and applied topics, with research projects clustered in four major themes: AGR, Magnox and exotic spent fuels; PuO{sub 2} and fuel residues; legacy ponds and silo wastes; and structural integrity. The consortium builds upon and consolidates the work of previous Research Councils' UK Energy Programme-funded projects in the same field although, importantly, this new project draws in researchers from a larger group of universities and increases the multi-disciplinary nature of the group. All participating research groups have a strong track-record of supporting the nuclear industry through basic and applied research as well as consultancy activities. Key aims of the consortium are to extend and develop a relevant academic skill base in the UK associated with the needs of the nuclear waste management industry, to train the next generation of UK researchers, equipping them with skills and experiences relevant to nuclear waste management and decommissioning issues, and to carry out cutting-edge research that has the potential to provide new and innovative pathways to better management of both legacy and future nuclear wastes. (authors)

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

Aging Hanford Nuclear Waste Using Carbon Dioxide to Evaluate Corrosion at Lower pH Limits - 18467

Samples of Hanford Nuclear Reservation (HNR) tank waste and simulated Hanford tank waste were exposed to carbon dioxide gas (CO{sub 2}) in the laboratory in order to decrease the pH of the solution. Sodium hydroxide is required to be added to some tanks according to waste handling specifications to keep tanks protected from pitting corrosion, but the maximum-allowed volume in some tanks is currently approaching capacity. Decreasing the pH of tank solutions using CO{sub 2} gas mimics the environmental exposure chemistry, does not add sodium, and allows for testing on solutions currently categorized as out-of-specification according to technical waste handling documents. Legacy alloy A537 Class 1 carbon steel was used to construct the AN tanks on the HNR and was utilized for this testing. The planned testing of three solutions included a simulant for feasibility and a waste solution from Tank 241-AN-102 (AN-102), taken in 2013, which was run in duplicate. The solutions were evaluated for corrosion potential using cyclic potentiodynamic polarization (CPP) scans to determine the propensity for stress corrosion cracking and pitting corrosion. Results in all solutions showed that pitting potential was low when the pH was above 11 and temperatures were below 40 deg. C. As solution pHs dipped into the 10- 10.5 range, there were mixed results. CPP scans were initially run at the higher temperature of 50 deg. C, accelerating corrosion rates. Solution pHs that did not indicate corrosion were further exposed to CO{sub 2}. Solutions with mixed or positive pitting results were rerun at 40 deg. C. The first failed run on the tank solution was seen when testing the duplicate sample at 50 deg. C and a pH of 13.01. When this solution was retested at 40 deg. C, the CPP scan did not show corrosion. A mixed corrosion result was obtained from a scan run at the final pH of 10 when tested at 50 deg. C. Upon completion of testing a visual inspection of the coupon did not show corrosion products on its surface. These results provide assurance that tanks containing slightly reduced pHs are still protected from pitting corrosion. Tank integrity assurance at a lower pH limit in Tank AN-102 could slow sodium addition and the rising volume of hazardous waste. Other benefits of reducing the pH specification would be reduced costs associated with retrieving and storing smaller volumes of hazardous waste, a reduced number of radiation exposure events (required for pH modification of tank waste), and a potential for a decreased volume required to be immobilized for long-term storage in a vitrified (glass) phase. (authors)

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

Panel Session 3: Featured Country Canada: Management and Disposal of High and Low-Level Waste

This panel featured Senior Executives accountable for the safe management and disposal of most of Canada's radioactive waste liabilities and provided their perspectives on current plans and progress made to date. Topics addressed by the panelists included national policies and programs, the regulatory framework, and actions led by the waste generators and solution implementers to ensure Canada's waste legacy is responsibly managed. Presentations proposed include: 1 - Overview of Canadian Radioactive Waste Policy and Long-Term Waste Management Projects (Dave McCauley, Natural Resources Canada (Canada)); 2 - Featured Country: Canada - National Repository (Laurie Swami, Nuclear Waste Management Organization (Canada)); 3 - Management and Disposal of Ontario Power Generation's Low and Intermediate Level Waste (Lise Morton, Ontario Power Generation (Canada)); 4 - Featured Country: Canada - National Laboratories Liabilities (Richard Sexton, Atomic Energy of Canada Limited (Canada)); 5 - Management and Disposal of High and Low-Level Waste (Mark Lesinski, Canadian Nuclear Laboratories (Canada)); 6 - Disposal in Canada: The Regulatory Perspective (Ramzi Jammal, Canadian Nuclear Safety Commission (Canada))

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

Improving Effectiveness of Waste Management Processes with Information and Communications Technology (ICT) - 19524

Improving the effectiveness of waste estimation, tracking, management and disposal processes is a key objective for Waste Management. Project Teams face common challenges producing waste estimates that are accurately accounted for in the project plan, tracking and reporting waste record actuals against the estimate, and communicating the status of waste through the organization. These challenges impact the effectiveness of waste management from a cost and schedule perspective, which can have a significant impact on the bottom line and on future business. By leveraging information and communications technology (ICT) waste management project teams can create a mobile workforce that closes the gaps between creating estimates and tracking actuals against estimates by gathering real time data at each step in the process. This results in significant gains on schedule and cost, improved communication and visibility across the project team, and an improvement in the overall effectiveness of waste processing and disposal procedures. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Panel Session 120: Roundtable: Waste Management - Energy Facilities Contractor Operating Group (EFCOG WM)

This Roundtable focused on the WM EFCOG working group as they met to discuss a variety of issues of importance to US DOE waste management operations. The purpose of the WM EFCOG is to seek out and promote the best management and operating practices, cost effective technologies and disposal options for all waste streams generated at US DOE facilities whether destined for US DOE or commercial facilities. Each site representative provided a radioactive waste management lessons learned briefing. Panelists with presentations: Savannah River Site (SRS) Solid Waste Program Update (Kerri Crawford); Idaho Clean-up Project Status (Frederick Hughes); West Valley Demonstration Project Update - EFCOG Waste Management Working Group (John Rendall); Key Project Challenges and Successes (Kalli Shupe); EFCOG WMWG Challenging Waste Subgroup Update (Tammy Monday); CH TRU Difficult Waste Stream Processing Challenges (Daniel Pancake); Argonne Building 350 Clean-up Success Using Effective Work Control (Daniel Dilday); Problematic Waste Streams on the Oak Ridge Reservation (John Wrapp)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Implementation of the Glycolate Destruction Process with Sodium Permanganate in the Defense Waste Processing Facility (DWPF) - 20141

The Savannah River Site (SRS) seeks to replace formic acid with glycolic acid as a chemical reductant in the Defense Waste Processing Facility (DWPF), where borosilicate glass is mixed with high-level radioactive waste, melted at high temperatures, then poured into stainless steel canisters for safe storage. Prior research and development have demonstrated the feasibility and advantages of the new nitric-glycolic acid flowsheet over the current nitric-formic acid flowsheet to chemically adjust the radioactive sludge slurry waste in the Sludge Receipt and Adjustment Tank (SRAT) prior to vitrification. Use of glycolic acid reduces hydrogen and ammonia generation during the reduction process, thus reducing flammability hazards and purge requirements in the DWPF processing vessels. In addition, glycolic acid will support the new Salt Waste Processing Facility (SWPF) by allowing for receipt of higher volumes of waste due to reduction of flammable gases, increased boil-up rates in the vessels, and easing the processing of future sludge batches containing high levels of mercury. However, during DWPF operations, trace amounts of glycolate are anticipated to be entrained in the recycle stream and sent to the Concentration, Storage, and Transfer Facilities (CSTF) via the Recycle Collection Tank (RCT). The RCT receives condensate from the Slurry Mix Evaporator Condensate Tank (SMECT) and Off-gas Condensate Tank (OGCT) that may contain unreacted glycolate. A literature review found the potential for hydrogen generation due to thermolysis of glycolate in caustic CSTF conditions. Savannah River National Laboratory (SRNL) conducted several tests on simulant and radioactive waste from various tanks at SRS and confirmed that glycolate added to waste at concentrations of approximately 1000 mg/L and higher generates hydrogen through thermolysis. There are potential operating scenarios in the future where glycolate concentration could exceed 1000 mg/L in the 2H Evaporator Drop Tank, the highest accumulation point for DWPF organics received via recycle. These findings presented a need to develop another process to mitigate the impact of glycolic acid to the CSTF. Several DWPF compatible options were evaluated for their ability to destroy glycolate in the DWPF recycle stream under various processing conditions, thereby mitigating its introduction to the CSTF. Downselection testing identified sodium permanganate as the most promising and simplest option to oxidize glycolate. It has been demonstrated to be effective in various RCT simulant compositions, operating temperatures, oxidant addition rates, solution pH, and initial glycolate concentrations. A feasibility study identified existing tanks within the facility that could be used for receiving and storing the commercially available sodium permanganate, as well as feeding it to the RCT for processing. The use of existing equipment as well as the ability to purchase the pre-mixed chemical reduces implementation and operational complexity. The downstream impacts of the sodium permanganate reaction were also evaluated and demonstrated to have minimal impact on other chemical species present in the RCT and CSTF, as well as on the materials of construction of the RCT and CSTF vessels and associated piping and instrumentation. Future work is in progress to validate the glycolate destruction process with testing in actual radioactive RCT waste before implementation in DWPF. (authors)

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

Small Waste in a Large Package - Meeting Requirements for Packaging, Transport and Disposal - 18092

A small amount of Class C Mixed Low Level Waste (MLLW) required packaging and disposition to an off-site facility. The AREVA TN RAM cask, designed and licensed for shipping Type B waste packages, was chosen as the most appropriate shipping solution. Due to packaging, shipping and disposal requirements, the standard TN RAM cask could not be utilized without making some modifications. Unique solutions and approaches had to be developed by the AREVA design team to complete the project within the anticipated budget and schedule. The general work scope was to characterize, remove from a pool, profile, package, certify and transport four irradiated components to an approved off-site facility. The material makeup of the components (three stainless steel plates and a lead counterweight) resulted in a MLLW classification which required special packaging and disposal methods. The AREVA design team worked with the disposal facility to identify all requirements associated with disposal of Class B/C MLLW. After defining the packaging and disposal requirements, it was determined that unique spacers and void fillers would be required. The design solution consisted of a liner insert as well as axial and radial spacers filled with inert material. Remaining voids in the liner insert were filled with recycled glass beads to fulfill the requirement for maximum 10% void space in the waste package. The axial spacers also served to center the waste load in the shipping cask to comply with the AREVA TN RAM Cask NRC license. Concentration averaging and waste consolidation were used to reach the Class C MLLW determination for shipping and disposal. This disposal method for Class C waste met the requirements of macro-encapsulation. Therefore, no additional treatment action was required when disposing of Class C MLLW. AREVA's solution provides a model for meeting macro-encapsulation requirements while also meeting void space requirements. This solution provides a model for how to adapt large shipping casks and liners to smaller waste packages that would not normally be a good fit for traditional casks. (authors)

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

Metal leaching from Lithium-ion and Nickel-metal hydride batteries and photovoltaic modules in simulated landfill leachates and municipal solid waste materials

Photovoltaic (PV) modules and batteries can either be recycled or disposed of in landfills at end-of-life (EoL). This work focuses on disposal since the benefit of recycling PV modules and batteries is well established. This study characterizes the potential toxicity due to metals leaching from selected PV modules and batteries through both the Toxicity Characteristic Leaching Procedure (TCLP) and in-house batch leaching protocols to probe the impact on metallic ion mobility as a function of the different types of e-waste entering the waste stream, the magnitude of device damage when placed into the waste stream, and the simulated municipal solid waste (SMSW) composition. Our results showed that one PV module and three battery types in this study should be classified as hazardous waste within the U.S. However, for some of the other e-wastes, metals of concern including Cr, Cu, Hg, Ni, Pb, and Zn leached during the batch tests but not in the TCLP regulatory method. For most of the waste types, the amounts of metals that leached in the TCLP test and batch tests were much lower than the total extractable amounts, demonstrating the potential for additional unaccounted for amounts of metals to leach. Our results demonstrate that the TCLP regulatory method might fail at predicting potential leaching and at capturing the complexity of e-waste leaching in landfill conditions. It confirms that additional work is needed urgently to develop appropriate EoL procedures for MSW with PV and battery e-waste.

42 ENGINEERING↗
DOE OSTI2023

A decision support tool for e-waste recycling operations using the hen-and-chicks bio-inspired optimization metaheuristic

E-waste from end-of-life electrical and electronic devices is one of the fastest growing waste streams from households and businesses. E-waste recycling yields environmental sustainability and economic benefits. Due to continuous changes in e-waste types and compositions, recycling businesses face challenges to optimize their operational configuration to achieve better economic and environmental performance. To help e-waste recyclers mitigate this problem, we have developed a modular decision support tool called the Comprehensive Manufacturing Assessment Tool (CMAT) that can simulate both e-waste recycling operations and economics. This tool can give valuable insights regarding the profitability of the entire operation and different e-waste types. In addition, a new bio-inspired metaheuristic optimization algorithm, hen-and-chicks optimization (HACO), was developed to assign manpower to different workstations to maximize operational efficiencies. According to the results of our case study, laptops, desktops, and computer peripherals are the three electronic waste products that produce the most profit. Our examination of the sensitivity of material prices shows that the price of steel has the most significant influence on total profit, because it is the most widely used material in the majority of electronic devices. We have released the decision support tool as open-source software under a general public license. It could be customized for other recycling industries beyond e-waste to achieve business sustainability by making their operations more efficient.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Thermal valorization of post-consumer film waste in a bubbling bed gasifier

Highlights: • Film waste from packaging is a common waste, a fraction of which is not recyclable. • Gasification can make use of the high energy value of the non-recyclable fraction. • This waste and two reference polymers were gasified in a bubbling bed reactor. • This experimental research proves technical feasibility of the process. • It also analyzes impact of composition and ER on the performance of the plant. - Abstract: The use of plastic bags and film packaging is very frequent in manifold sectors and film waste is usually present in different sources of municipal and industrial wastes. A significant part of it is not suitable for mechanical recycling but could be safely transformed into a valuable gas by means of thermal valorization. In this research, the gasification of film wastes has been experimentally investigated through experiments in a fluidized bed reactor of two reference polymers, polyethylene and polypropylene, and actual post-consumer film waste. After a complete experimental characterization of the three materials, several gasification experiments have been performed to analyze the influence of the fuel and of equivalence ratio on gas production and composition, on tar generation and on efficiency. The experiments prove that film waste and analogue polymer derived wastes can be successfully gasified in a fluidized bed reactor, yielding a gas with a higher heating value in a range from 3.6 to 5.6 MJ/m{sup 3} and cold gas efficiencies up to 60%.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2014

Packaging waste recycling in Europe: Is the industry paying for it?

Highlights: • We study the recycling schemes of France, Germany, Portugal, Romania and the UK. • The costs and benefits of recycling are compared for France, Portugal and Romania. • The balance of costs and benefits depend on the perspective (strictly financial/economic). • Financial supports to local authorities ought to promote cost-efficiency. - Abstract: This paper describes and examines the schemes established in five EU countries for the recycling of packaging waste. The changes in packaging waste management were mainly implemented since the Directive 94/62/EC on packaging and packaging waste entered into force. The analysis of the five systems allowed the authors to identify very different approaches to cope with the same problem: meet the recovery and recycling targets imposed by EU law. Packaging waste is a responsibility of the industry. However, local governments are generally in charge of waste management, particularly in countries with Green Dot schemes or similar extended producer responsibility systems. This leads to the need of establishing a system of financial transfers between the industry and the local governments (particularly regarding the extra costs involved with selective collection and sorting). Using the same methodological approach, the authors also compare the costs and benefits of recycling from the perspective of local public authorities for France, Portugal and Romania. Since the purpose of the current paper is to take note of who is paying for the incremental costs of recycling and whether the industry (i.e. the consumer) is paying for the net financial costs of packaging waste management, environmental impacts are not included in the analysis. The work carried out in this paper highlights some aspects that are prone to be improved and raises several questions that will require further research. In the three countries analyzed more closely in this paper the industry is not paying the net financial cost of packaging waste management. In fact, if the savings attained by diverting packaging waste from other treatment (e.g. landfilling) and the public subsidies to the investment on the “recycling system” are not considered, it seems that the industry should increase the financial support to local authorities (by 125% in France, 50% in Portugal and 170% in Romania). However, in France and Portugal the industry is paying local authorities more than just the incremental costs of recycling (full costs of selective collection and sorting minus the avoided costs). To provide a more definitive judgment on the fairness of the systems it will be necessary to assess the cost efficiency of waste management operators (and judge whether operators are claiming costs or eliciting “prices”)

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

A review of technologies and performances of thermal treatment systems for energy recovery from waste

Highlights: • The topic of energy recovery from waste by thermal treatment is reviewed. • Combustion, gasification and pyrolysis were considered. • Data about energy recovery performances were collected and compared. • Main limitations to high values of energy performances were illustrated. • Diffusion of energy recovery from waste in EU, USA and other countries was discussed. - Abstract: The aim of this work is to identify the current level of energy recovery through waste thermal treatment. The state of the art in energy recovery from waste was investigated, highlighting the differences for different types of thermal treatment, considering combustion/incineration, gasification and pyrolysis. Also different types of wastes – Municipal Solid Waste (MSW), Refuse Derived Fuel (RDF) or Solid Refuse Fuels (SRF) and some typologies of Industrial Waste (IW) (sludge, plastic scraps, etc.) – were included in the analysis. The investigation was carried out mainly reviewing papers, published in scientific journals and conferences, but also considering technical reports, to gather more information. In particular the goal of this review work was to synthesize studies in order to compare the values of energy conversion efficiencies measured or calculated for different types of thermal processes and different types of waste. It emerged that the dominant type of thermal treatment is incineration associated to energy recovery in a steam cycle. When waste gasification is applied, the produced syngas is generally combusted in a boiler to generate steam for energy recovery in a steam cycle. For both the possibilities – incineration or gasification – cogeneration is the mean to improve energy recovery, especially for small scale plants. In the case of only electricity production, the achievable values are strongly dependent on the plant size: for large plant size, where advanced technical solutions can be applied and sustained from an economic point of view, net electric efficiency may reach values up to 30–31%. In small-medium plants, net electric efficiency is constrained by scale effect and remains at values around 20–24%. Other types of technical solutions – gasification with syngas use in internally fired devices, pyrolysis and plasma gasification – are less common or studied at pilot or demonstrative scale and, in any case, offer at present similar or lower levels of energy efficiency.

09 BIOMASS FUELS↗
DOE OSTI2013

Data sharing report characterization of population 7: Personal protective equipment, dry active waste, and miscellaneous debris, surveillance and maintenance project Oak Ridge National Laboratory Oak Ridge, Tennessee

The U.S. Department of Energy (DOE) Oak Ridge Office of Environmental Management (EM-OR) requested that Oak Ridge Associated Universities (ORAU), working under the Oak Ridge Institute for Science and Education (ORISE) contract, provide technical and independent waste management planning support under the American Recovery and Reinvestment Act (ARRA). Specifically, DOE EM-OR requested that ORAU plan and implement a sampling and analysis campaign targeting certain URS|CH2M Oak Ridge, LLC (UCOR) surveillance and maintenance (S&M) process inventory waste. Eight populations of historical and reoccurring S&M waste at the Oak Ridge National Laboratory (ORNL) have been identified in the Waste Handling Plan for Surveillance and Maintenance Activities at the Oak Ridge National Laboratory, DOE/OR/01-2565&D2 (WHP) (DOE 2012) for evaluation and processing to determine a final pathway for disposal. Population 7 (POP 7) consists of 56 containers of aged, low-level and potentially mixed S&M waste that has been staged in various locations around ORNL. Several of these POP 7 containers primarily contain personal protective equipment (PPE) and dry active waste (DAW), but may contain other miscellaneous debris. This data sharing report addresses the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) specified waste in a 13-container subpopulation (including eight steel boxes, three 55-gal drums, one sealand, and one intermodal) that lacked sufficient characterization data for possible disposal at the Environmental Management Waste Management Facility (EMWMF) using the approved Waste Lot (WL) 108.1 profile.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2014

SRNL CRP progress report [Development of Melt Processed Ceramics for Nuclear Waste Immobilization]

A multi-phase ceramic waste form is being developed at the Savannah River National Laboratory (SRNL) for treatment of secondary waste streams generated by reprocessing commercial spent nuclear. The envisioned waste stream contains a mixture of transition, alkali, alkaline earth, and lanthanide metals. Ceramic waste forms are tailored (engineered) to incorporate waste components as part of their crystal structure based on knowledge from naturally found minerals containing radioactive and non-radioactive species similar to the radionuclides of concern in wastes from fuel reprocessing. The ability to tailor ceramics to mimic naturally occurring crystals substantiates the long term stability of such crystals (ceramics) over geologic timescales of interest for nuclear waste immobilization [1]. A durable multiphase ceramic waste form tailored to incorporate all the waste components has the potential to broaden the available disposal options and thus minimize the storage and disposal costs associated with aqueous reprocessing.

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

Experimental Determination and Thermodynamic Modeling of Electrical Conductivity of SRS Waste Tank Supernate

SRS High Level Waste Tank Farm personnel rely on conductivity probes for detection of incipient overflow conditions in waste tanks. Minimal information is available concerning the sensitivity that must be achieved such that that liquid detection is assured. Overly sensitive electronics results in numerous nuisance alarms for these safety-related instruments. In order to determine the minimum sensitivity required of the probe, Tank Farm Engineering personnel need adequate conductivity data to improve the existing designs. Little or no measurements of liquid waste conductivity exist; however, the liquid phase of the waste consists of inorganic electrolytes for which the conductivity may be calculated. Savannah River Remediation (SRR) Tank Farm Facility Engineering requested SRNL to determine the conductivity of the supernate resident in SRS waste Tank 40 experimentally as well as computationally. In addition, SRNL was requested to develop a correlation, if possible, that would be generally applicable to liquid waste resident in SRS waste tanks. A waste sample from Tank 40 was analyzed for composition and electrical conductivity as shown in Table 4-6, Table 4-7, and Table 4-9. The conductivity for undiluted Tank 40 sample was 0.087 S/cm. The accuracy of OLI Analyzer™ was determined using available literature data. Overall, 95% of computed estimates of electrical conductivity are within ±15% of literature values for component concentrations from 0 to 15 M and temperatures from 0 to 125 °C. Though the computational results are generally in good agreement with the measured data, a small portion of literature data deviates as much as ±76%. A simplified model was created that can be used readily to estimate electrical conductivity of waste solution in computer spreadsheets. The variability of this simplified approach deviates up to 140% from measured values. Generally, this model can be applied to estimate the conductivity within a factor of two. The comparison of the simplified model to pure component literature data suggests that the simplified model will tend to under estimate the electrical conductivity. Comparison of the computed Tank 40 conductivity with the measured conductivity shows good agreement within the range of deviation identified based on pure component literature data.

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

Conceptual Waste Packaging Options for Deep Borehole Disposal

This report presents four concepts for packaging of radioactive waste for disposal in deep boreholes. Two of these are reference-size packages (11 inch outer diameter) and two are smaller (5 inch) for disposal of Cs/Sr capsules. All four have an assumed length of approximately 18.5 feet, which allows the internal length of the waste volume to be 16.4 feet. However, package length and volume can be scaled by changing the length of the middle, tubular section. The materials proposed for use are low-alloy steels, commonly used in the oil-and-gas industry. Threaded connections between packages, and internal threads used to seal the waste cavity, are common oilfield types. Two types of fill ports are proposed: flask-type and internal-flush. All four package design concepts would withstand hydrostatic pressure of 9,600 psi, with factor safety 2.0. The combined loading condition includes axial tension and compression from the weight of a string or stack of packages in the disposal borehole, either during lower and emplacement of a string, or after stacking of multiple packages emplaced singly. Combined loading also includes bending that may occur during emplacement, particularly for a string of packages threaded together. Flask-type packages would be fabricated and heat-treated, if necessary, before loading waste. The fill port would be narrower than the waste cavity inner diameter, so the flask type is suitable for directly loading bulk granular waste, or loading slim waste canisters (e.g., containing Cs/Sr capsules) that fit through the port. The fill port would be sealed with a tapered, threaded plug, with a welded cover plate (welded after loading). Threaded connections between packages and between packages and a drill string, would be standard drill pipe threads. The internal flush packaging concepts would use semi-flush oilfield tubing, which is internally flush but has a slight external upset at the joints. This type of tubing can be obtained with premium, low-profile threaded connections at each end. The internal-flush design would be suitable for loading waste that arrives from the originating site in weld-sealed, cylindrical canisters. Internal, tapered plugs with sealing filet welds would seal the tubing at each end. The taper would be precisely machined onto both the tubing and the plug, producing a metal-metal sealing surface that is compressed as the package is subjected to hydrostatic pressure. The lower plug would be welded in place before loading, while the upper plug would be placed and welded after loading. Conceptual Waste Packaging Options for Deep Borehole Disposal July 30, 2015 iv Threaded connections between packages would allow emplacement singly or in strings screwed together at the disposal site. For emplacement on a drill string the drill pipe would be connected directly into the top package of a string (using an adapter sub to mate with premium semi-flush tubing threads). Alternatively, for wireline emplacement the same package designs could be emplaced singly using a sub with wireline latch, on the upper end. Threaded connections on the bottom of the lowermost package would allow attachment of a crush box, instrumentation, etc.

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

Spectroscopic Properties of Tc(I) Tricarbonyl Species Relevant to the Hanford Tank Waste

Technetium-99 (Tc) exists predominately in soluble forms in the liquid supernatant and salt cake fractions of the nuclear tank waste stored at the U.S. DOE Hanford Site. In the strongly alkaline environments prevalent in the tank waste, its dominant chemical form is pertechnetate (TcO4-, oxidation state +7). However, attempts to remove Tc from the Hanford tank waste using ion-exchange processes specific to TcO 4 - only met with limited success, particularly processing tank waste samples containing elevated concentrations of organic complexants. This suggests that a significant fraction of the soluble Tc can be present as non-pertechnetate low-valent Tc (oxidation state < +7) (non-pertechnetate). The chemical identities of these non-pertechnetate species are poorly understood. Previous analysis of the SY-101 and SY-103 tank waste samples provided strong evidence that non-pertechnetate can be comprised of [Tc(CO) 3 ] + complexes containing Tc in oxidation state +1 (Lukens et al. 2004). During the last two years, our team has expanded this work and demonstrated that high-ionic-strength solutions typifying tank waste supernatants promote oxidative stability of the [Tc(CO) 3 ] + species (Rapko et al. 2013; Levitskaia et al. 2014). It also was observed that high-ionic-strength alkaline matrices stabilize Tc(VI) and potentially Tc(IV) oxidation states, particularly in presence organic chelators, suggesting that the relevant Tc compounds can serve as important redox intermediates facilitating the reduction of Tc(VII) to Tc(I). Designing strategies for effective Tc processing, including separation and immobilization, necessitates understanding the molecular structure of these non-pertechnetate species and their identification in the actual tank waste samples. To-date, only limited information exists regarding the nature and characterization of the Tc(I), Tc(IV), and Tc(VI) species. One objective of this project is to identify the form of non-pertechnetate in the Hanford waste. To do this, we are developing a spectral library of reference non-pertechnetate compounds that can be compared against actual waste samples. The emphasis of the fiscal year 2015 work was Tc(I) tricarbonyl [Tc(CO) 3 ] + compounds. The key findings are summarized below.

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

Summary Report of Comprehensive Laboratory Testing to Establish the Effectiveness of Proposed Treatment Methods for Unremediated and Remediated Nitrate Salt Waste Streams

The inadvertent creation of transuranic waste carrying hazardous waste codes D001 and D002 requires the treatment of the material to eliminate the hazardous characteristics and allow its eventual shipment and disposal at the Waste Isolation Pilot Plant (WIPP). This report documents the effectiveness of two treatment methods proposed to stabilize both the unremediated and remediated nitrate salt waste streams (UNS and RNS, respectively) at Los Alamos National Laboratory (LANL). The two technologies include the addition of zeolite (with and without the addition of water as a processing aid) and cementation. Surrogates were developed to evaluate both the solid and liquid fractions expected from parent waste containers, and both the solid and liquid fractions were tested. Both technologies are shown to be effective at eliminating the characteristic of ignitability (D001), and the addition of zeolite was determined to be effective at eliminating corrosivity (D002), with the preferred option1 of adding zeolite currently planned for implementation at LANL’s Waste Characterization, Reduction, and Repackaging Facility (WCRRF). The course of this work verified the need to evaluate and demonstrate the effectiveness of the proposed remedy for debris material, if required. The evaluation determined that WypAlls, cheesecloth, and Celotex absorbed with saturated nitrate salt solutions exhibit the ignitability characteristic (all other expected debris is not classified as ignitable). Finally, liquid surrogates containing saturated nitrate salts did not exhibit the characteristic of ignitability in their pure form (those neutralized with Kolorsafe and mixed with sWheat did exhibit D001). Sensitivity testing and an analysis were conducted to evaluate the waste form for reactivity. Tests included subjecting surrogate material to mechanical impact, friction, electrostatic discharge and thermal insults. The testing confirmed that the waste does not exhibit the characteristic of reactivity (D003). Follow-on testing was conducted to demonstrate the effectiveness of zeolite stabilization for ignitable WypAll and cheesecloth debris and additional nitrate salt solutions (those exhibiting the oxidizer characteristic) to demonstrate the effectiveness of the remedy. Follow-on testing also included testing of surrogate materials containing Waste Lock 770, which is present in four of the RNS containers, and potential items of debris such as plywood and Celotex material. Testing to evaluate the effectiveness of the remedy was performed using the specific remediation processes that are planned for use at the WCRRF. Finally, testing was also performed to evaluate the holding capacity of zeolite using a highly acidic surrogate solution and to characterize the composition of gases generated during mixing of zeolite with surrogate solutions. All these tests demonstrated the effectiveness of adding zeolite as the planned remedy.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗