Past Research Projects
Separated waste stream immobilization of iodine and offgas caustic scrubber solution
This project aims to produce a set of waste forms from separation of iodine from the caustic offgas scrubber solution. The primary caustic scrub containing iodine, halides, and carbonate will be immobilized in a glass-bonded composite of cancrinite/sodalite. The iodine-loaded silver sorbent will be stripped of iodine, converted to NaI, and immobilized into a separate durable glass-bonded iodosodalite waste form. (Partners: Rutgers, PNNL, ANSTO; Funding DOE-NEUP)
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Conversion of common DSP minerals into 2:1-type clay minerals
Highly alkaline iron, aluminum, and titanium-rich tailings and refining wastes are the abundant end-products of the bauxite mining and aluminum refining industries. Worldwide, estimates of these bauxite residue stockpiles exceed 3 billion tons, with approximately 130 million tons produced every year. In the current research, we studied the synthesis of feldspathoids and their subsequent dissolution and mineral transformation. A synthetic mixture of sodalite/cancrinite was designed to be similar to the desilication products (DSP) produced during the Bayer process. These DSP materials were then transformed using a simple process to useful materials for soil amendment. (Funding: Emirates Global Aluminum) Related publications
Supply Chain Data Science – Critical Materials Decision Support System Based on Machine Learning: Battery Materials Case Study
This seed project aims to begin construction of a high-level data analysis and decision support tool for understanding supply chain issues with critical materials. To achieve this objective, data will be harvested from a wide range of literature resources from government, private, and scientific communities, organized in a useful fashion, and advanced decision-making methods (including data science, machine learning, and decision support systems) will be applied. (Partners: Microsoft; Funding JCDREAM)
Simulated Used Nuclear Fuel Dissolution as a Function of Fuel Chemistry and Near Field Conditions
This project will develop a fundamental and transformative understanding of the various effects of simulated used nuclear fuel (UNF) microstructure on its dissolution in geologic repository conditions, through an integrated research program. This understanding will underpin the maturation of models for UNF evolution and interaction under different potential repository conditions, enabling reliable prediction of degradation and adjustment of repository conditions to achieve desired long-term performance, and providing increased confidence in predicting behavior for up to one million years. (Partners: PNNL, University of Sheffield; Funding DOE-NEUP)
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Technetium Local Structure and Chemistry in Low Activity Waste Glass
We will obtain first-of-a-kind chemical structure determination of poorly understood, environmentally relevant technetium compounds. Through the investigation of model alkali oxide 99Tc compounds and 99Tc-containing oxide glasses we intend to provide key data on glass structure around 99Tc , the stability of the waste glass, and its corrosion in water. There are several known polymorphs of Tc-oxide and the transformation between these phases will be examined. Search algorithms will be used to identify additional Tc-oxide phases. This work provides much needed data for the improvement of performance assessment models of Tc release in waste repositories. (Partners: PNNL, EMSL, LBNL, ORNL; Funding: DOE-ORP)
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Concentrated pertechnic acid
Studies and Analyses of Compositional Dependence of Glass Corrosion Associated with Nepheline Formation
We will systematically explore nepheline crystallization and chemical durability with simplified glass systems, starting with various Na2O-SiO2-Al2O3 compositions, then building complexity to add several other important components, such as CaO, B2O3, Li2O, and Fe2O3. By this tiered approach we will build on the understanding of the effects of the different components on the susceptibility to nepheline formation in complex nuclear waste glasses for immobilization of Hanford wastes. Data-driven, machine-learning models will be created to predict the formation of nepheline as a function of glass composition and thermal treatment. The interpretation of these models will provide quantitative insight to the forces driving nepheline crystallization in high-level waste glasses. (Partners: PNNL, Rutgers; Funding: DOE-ORP)
Related Publications
Formation and Alteration of Old Glass
This project focuses on studying and analyzing natural and anthropomorphic analogue glasses of great age for the purposes of testing glass alteration models needed to predict long term performance of nuclear waste glass after disposal. One focus is on glasses from the Swedish hillfort Broborg, and includes rock melting experiments, characterization, and glass synthesis, with the goals of providing sufficient understanding of the ancient process that suitable synthetic glasses can be made in the laboratory for alteration testing. Additionally, we are exploring natural geologic glass and other archaeological glasses to see if any other readily available and relevant materials might be available and appropriate for study. (Partners: PNNL, Sheffield, Tekedo, Smithsonian; Funding: DOE-ORP)
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Understanding the fundamental science governing the development and performance of nuclear waste glasses
The goal of this Integrated Research Program is to supply actionable information to DOE to reduce costs and risks associated with nuclear waste vitrification. Primary information will be compositional dependence and glass chemistry effects on undesirable processing outcomes such as low waste loading, crystal formation, technetium volatility, and salt formation. (Partners: Rutgers, University of North Texas, PNNL; Funding DOE-NE with DOE-EM)
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ZnS scintillator for high resolution X-ray imaging at 9 keV
Rapid integrated circuit (IC) inspection using x-ray microscopy requires novel X-ray scintillating materials with high efficiency and high spatial resolution. Current scintillator materials, such as Cesium Iodide (CsI), suffer from a trade-off between efficiency and spatial resolution. Novel materials which can be produced with improved brightness and decreased afterglow are necessary to address the stringent requirements of fast, high resolution X-ray microscopy. (Partners: CeraNova, WSU Center for Materials Research; Funding: DOD-DMEA)
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Apatite and sodalite based glass-bonded waste forms for immobilization of 129I and mixed halide radioactive wastes
We will develop chemically durable glass-bonded ceramic waste forms for immobilization of 129I and mixed halide wastes with focus on: (i) low-temperature synthesis (<200°C) of ceramic minerals and (ii) design of glass compositions with high chemical durability and good sintering ability at temperatures <800°C . Calcium phosphate (CaP) apatite [Ca5(PO4)3X] and sodalite [Na8(AlSiO4)6X2], containing halides (X = Cl, I) will be synthesized at low temperatures using various solution-based synthesis routes to prevent halide volatility, and these minerals will further be consolidated to monolithic waste forms using borosilicate (for sodalite) and phosphate (for CaP-apatite) glass-binders. (Partners: Rutgers, PNNL; Funding: DOE-NEUP)
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Understanding influence of thermal history and glass chemistry on kinetics of phase separation and crystallization in borosilicate glass-ceramic waste forms for aqueous reprocessed high level waste
We will develop a fundamental and transformative understanding of the crystallization mechanisms in complex glass-ceramic high level waste (HLW) wasteforms. This understanding will underpin the maturation of glass ceramic manufacture, by linking process variables to molecular scale mechanisms, enabling reliable production of wasteforms to the desired specification. (Partners: PNNL, Rutgers, University of Sheffield, Warwick University; Funding DOE-NEUP)
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Advanced models for nondestructive evaluation of aging nuclear power plant cables
The objectives of this project are (i) develop advanced, validated models relating microstructural and chemical changes, due to thermal exposure, radiation exposure and water immersion, in cable insulation polymers to observable changes in dielectric, terahertz (THz) and infrared (IR) frequency spectra, (ii) identify the frequencies which most sensitively indicate microstructural and chemical changes in these polymers, and (iii) develop advanced, validated models of the response of novel cable nondestructive evaluation methods; capacitive, THz and infrared, to cable aging as a function of thermal, radiation and/or water exposure. (Partners: ISU, PNNL; Funding DOE-NEUP)
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Use of Micro- and Meso-scale Magnetic Characterization Methods to Study Degradation of Reactor Structural Material
We will integrate microstructural metrology, micro-magnetic measurements, and meso-scale phase field modeling to develop advanced tools and techniques that can extract semi-quantitative diagnostic and interpretive information about the state of microstructural damage in a material based on magnetic signature data alone. Improved diagnostic information about materials degradation will greatly enhance reactor safety by reducing uncertainty in assigning safety margins for materials currently in service and for new materials currently in development. This technology has potential for maturation into real-time, in-situ monitoring capability. (Partners: PNNL; Funding: DOE-NEUP)
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