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Current Research Projects

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)

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-NEUP with DOE-ORP)

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)

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-A
l2O3 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.  (Partners:  PNNL, Rutgers; Funding: DOE-ORP)

Representation of nepheline structure viewed down [001]

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.  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)

Past Research Projects

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
)

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)

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)

MFM image of Poly Fe