Pyroprocessing technology--theoretical and experimental studies in electrorefinery, oxide reduction and chemistry, and ion exchange. Interfacial phenomena and multi-phase flow systems involving in nuclear and chemical engineering applications.
• B.S. Nuclear Engineering – University of Maryland, College
Park, 1997
• Ph.D. Chemical Engineering – University of Maryland,
College Park, 2001
• Postdoctoral Study – National Research Council Fellowship,
Naval Research
Laboratory, Washington, D. C.,
2001–2004
Research Statement
Development of New Chemical Engineering Applications in Pyroprocessing Technology
Spent fuel from the Experimental Breeder Reactor-II (EBR-II) is currently being treated in electrorefiners at the Idaho National Laboratory (INL) in a process known as pyroprocessing of spent nuclear fuel. In electrorefining, uranium is oxidized at the anode while simultaneously being reduced and deposited at the cathode. Plutonium, sodium, and fission products are oxidized to form chlorides in the electrolyte, which consists primarily of eutectic LiCl-KCl. The overall objective of pyroprocessing is to separate uranium from fission products and other actinides, both groups of elements of which can be placed into waste forms for long term storage in geological repository.
Development of Models for Pyrochemical Electrorefiners
Electrorefiners (ERs) including Mk-IV and Mk-V, central elements in the pyroprocessing technology, are currently operational to treat driver and blanket fuels, respectively. In spite of successful test results, multi-dimensional computational models essential for design and operation analysis of advanced processors are still lacking. This research focuses on developing multidimensional (2D and 3D) computational and statistical models for applications in order to improve operations of current electrorefiners. In addition, these models will be used to validate against compiled and evaluated experimental data to provide better developments of advanced ER’s for actinides recovery.
Mock-up Experiments for Oxide Reduction
In the study for reduction experiments with irradiated fuel, the cell design consists of a metal basket cathode containing the oxide, an oxygen-evolving anode, and a lithium guard electrode all flooded with a molten salt electrolyte. Previous experimental results show that there were salt formations on the top plate of the vessel above the anode region. It is suspected that the existence of this salt formation is due to the splashing of jet drops produced by bubbles bursting at the free surface inside the electrochemical cell and this occurring event is related to the bubble population generated on the anode surface. These issues have not been thoroughly investigated and therefore they provide the motivation for the mock-up studies. The thrust of this research is to theoretically predict and experimentally assess these concerns by developing fundamental mock-up designs and analyzes.
Ion Exchange Technology
An ion exchange process has been considered for minimizing ceramic waste volume generated from the pyroprocessing method for treating spent nuclear fuel. This research focuses on the nature of the interactions between various molten chloride salts and zeolite—experimental and theoretical perspectives. Predictive information is necessary to help design and optimize an ion exchange process. The principal challenge is to develop a model that is sufficiently sophisticated to capture a realistic physiochemistry for ion exchange while still being simplistic enough to fit to available data.
Development and Application of in-situ Elemental Analysis in Molten Salt System via Laser Induced Breakdown Spectroscopy (LIBS) Technique
The primary objective of this research is to develop a technology to remotely measure and analyze the real time concentrations of special nuclear materials in process streams in spent fuel reprocessing facilities. Specifically, the application of a state-of-the-art analytical technique, Laser Induced Breakdown Spectroscopy (LIBS), in spent fuel reprocessing facilities, such as pyroprocessing and aqueous processing, will be investigated. LIBS is an elemental analysis method based on the emission from a plasma generated by focusing a laser beam at the interface of the medium to be sampled. This technology has been reported to be applicable to the media of solids, liquids (including molten metals), and gases. The advantages of applying the technology for reprocessing facilities are: (1) Rapid real-time elemental analysis—one measurement/laser pulse, or average spectra from multiple laser pulses for greater accuracy in < 1 minute, (2) Direct detection of elements and impurities in the system with low detection limits—element specific, ranging from 2-1000 ppm for most elements, and (3) Nearly non-destructive elemental analysis (about 1 mg material).