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Current Research

Active Grants and Projects

  • Development of a Self-Consistent Model of Plutonium Sorption: Quantification of Sorption Enthalpy and Ligand-Promoted Dissolution
    abstract coming soon
  • Quantification of Cation Sorption to Engineered Barrier Materials Under Extreme Conditions

    Objective: The objective of this work is to quantify interactions of risk driving radionuclides with engineered barrier materials used in radioactive waste repositories. The engineered solids to be examined will be iron oxide byproducts of steel corrosion and bentonite clays as representative backfill materials. Data examining sorption and ion exchange of various radionuclides to these materials are available. However, data are lacking for studies at high temperatures and high ionic strengths. The high ionic strength is expected to limit sorption of cations due to competition for a finite number of sorption and/or exchange sites. However, as temperature increases, sorption of actinide ions is hypothesized to increase based on an entropy driven displacement of solvating waters. Therefore studies at extremely high ionic strengths and at high temperatures are necessary. We will use a suite of actinide ions in these experiments to allow for a systematic and quantitative understanding of ion interactions with these materials as a function of ion size, hydration state, and charge. The deliverable will be a qualitative conceptual model and a quantitative thermodynamic aqueous/surface complexation speciation model describing actinide sorption to engineered barrier materials, which is based upon a mechanistic understanding of specific sorption processes as determined from both micro-scale and macro-scale experimental techniques.

    Hypotheses: The overarching hypothesis of this research is that strong actinide interactions with metal (oxyhydr)oxide surfaces are manifested by large stability constants for the actinide surface complexes. These large stability constants are due to positive entropies which are mechanistically driven by displacement of solvating water molecules from the actinide ion and the mineral surface during sorption and/or surface precipitation. Such entropies are accessible through measurement of sorption enthalpies and stability constants using surface complexation modeling and calorimetric titration techniques. Additional specific hypotheses that are corollaries to this general hypothesis are:

    • Dehydration of metal ions upon sorption may provide an energetic barrier to desorption.
    • The ability of bentonite clay to sequester radionuclides can be enhanced via amendment of the clay with functionalized or redox active materials such as fly ash or zeolites.


    Outcomes: This work directly addresses the expressed need in Technical Work Scope Identifier FC-6 for understanding “aqueous speciation and surface sorption at high temperature and high ionic strengths anticipated in near field conditions.” The primary deliverable will be a set of thermodynamically based sorption and ion exchange constants describing radionuclide sorption to engineered barrier materials. These data will provide an understanding of the fundamental reaction mechanisms occurring at the mineral-water interface. A greater understanding of these processes will reduce the uncertainty in strategies for sequestration of radionuclide bearing wastes. Overall this project will increase our understanding of radionuclide interfacial reactions and help to ensure human and environmental health are protected during treatment and disposal of radionuclide bearing wastes.

  • Ultra-Trace Level Quantification of Alpha- and Beta- Emitting Radionuclides with Extractive Scintillating Resin

    The objective of this research is to advance scientific understanding in the development of high-selectivity sensor materials, high-sensitivity sensors, and data analysis techniques for ultra-trace-level quantification of radionuclides, particularly α- and β-emitting radionuclides. An on-line system for ultra-low-level detection of α- and β-emitting radionuclides in environmental media (water, air and sewage) would be a powerful nuclear forensics tool. Currently, no such system is available.

    Scope:

    1. Design, synthesize, and characterize a new class of extractive scintillator resins that incorporate covalently bound scintillator molecules and selective ligands for α- and β-emitting radionuclides. We will prepare two resin platforms for comparative testing: one incorporates ligands continuously throughout the resin matrix and the other isolates ligands within a polymer nanolayer adjacent to the resin-solution interface. The second type of resin will be prepared by grafting ligand-rich nanolayers from the resin surface using surface-initiated atom transfer radical polymerization (ATRP). Study variables include scintillator and ligand type, monomer composition in the formulation, and polymerization time. Focus in Years 1-3 will be given to development of extractive scintillation resins for Sr, Tc, U. Years 4-5 would focus on the development of resins for Cs and Pu.
    2. Quantify the fundamental parameters that control the sensitivity of the extractive scintillator sensor. Using deterministic and Monte Carlo techniques, we will assess trade-offs among resin size, flow-cell diameter and geometry, energy deposition in the scintillator, light collection efficiency, radionuclide selectivity, type of radiation, and resin capacity. Preliminary calculations show that detection of alpha radiation below mBq/L levels is possible. The focus for the first 1.5 years will be on the charged particle modeling. From year 1.5 – 3.0 our team will work on the light collection model. While in year 3, we will begin to work on the combined energy deposition and light collection models. This effort will extend into years 4 and 5.
    3. Develop statistical control chart methods that will lower the detection limit of the sensors developed under Tasks 1 and 2. Preliminary tests indicate that some control chart methods are significantly more sensitive to detection of small changes in count rate over conventional paired analyses. The ability of the control chart to improvement the detection limit is expected to be an order of magnitude or better. During years 1 and 2 our team will concentrate on control chart data using count rate data. During year 2 and 3 our team will develop the control chart methods using the time-interval data.
  • Synthesis-Microstructure-Performance Relations in Oxide Ceramic Scintillators

    Scintillators are unique materials that transform high energy ionizing radiation into detectable visible light, being used for the detection and measurement of radiation in security, energy, medical diagnosis, and other strategic fields. Presently, there is a knowledge gap relating the fabrication and processing conditions of transparent ceramic scintillators with their scintillation output, a situation that negatively impacts the widespread use of these materials, as well as undermines their performance. We hypothesize that the intensities of scintillation and afterglow are related to the concentration of structural imperfections that generate electronic traps, and that it is possible to mitigate afterglow by identifying suitable rare earth (RE) dopants to drain charge carriers off the traps. In order to evaluate the above hypothesis, it is proposed to:

    1. Investigate the effect of grain boundary density on the scintillation efficiency and afterglow intensity and duration. Manipulation of grain size will be promoted by controlled thermal treatments in vacuum and characterized by electron microscopy,
    2. Investigate the effect of oxygen non-stoichiometry on the scintillation efficiency and afterglow intensity and duration. Systematic variation of the oxygen content will be promoted by controlled thermal treatments under O2 and reducing atmospheres and monitored by compositional analysis,
    3. Develop a predictive capability to identify suitable RE dopants to decrease afterglow intensity and duration. Traps energy depth will be determined by thermoluminescence measurements, and identification of suitable RE dopants to drain charge carriers off these traps will be based on Dorenbos model of RE energy levels within the band gap.


    The innovative aspect of the proposed research is to go beyond the fabrication of transparent ceramics to establish relations between fabrication conditions, microstructure and defect characteristics with afterglow and scintillation performance, and to develop a predictive capability to identify RE dopants to mitigate afterglow. The project will focus on RE-doped Lu2O3, Y2O3, and Y3Al5O12 transparent ceramics.

  • Alternative Sample Loading Preparation for Thermal Ionization Mass Spectrometry

    The objectives of this project are to design and test an alternative sample loading method for thermal ionization mass spectrometry (TIMS) analysis. TIMS is one of the most sensitive analytical tools for determining isotopic ratios for plutonium and uranium and is used widely within the nuclear nonproliferation and safeguards communities. This work seeks to introduce a polymer thin film based method for loading samples that would replace the traditional ‘bead loading’ method. This thin film system has the potential to decrease sample preparation time, increase sensitivity, and minimize the risk of sample loss due to explosive decompression commonly observed using the current bead loading technique.

    The project team has extensive experience in radioisotope detection and measurement, radiochemical separations, and the surface engineering technologies required to produce the thin films to be utilized in this work. Here is a summary of methods to be employed by this team:

    Thin film coating: Degassed rhenium ribbons will be coated with a thin film of type 1 strong anion-exchange polymer. Polymer thin films will be deposited on the ribbons using a dip-coating method. The experiments will focus on elucidating the impacts of solvents, polymer solution concentration, and dip-coating withdrawal speed on film thickness. A theoretical framework for thin film formation will be used to guide experimental design. Characterization will verify uniform coating of rhenium ribbons by the polymer films and will determine their thickness values.

    Sample loading: These experiments will examine methods for loading uranium and plutonium from solutions onto the ribbons, determine the uptake kinetics, and determine loading capacities. Three methods will be used to load uranium and plutonium onto the coated ribbons: Static batch uptake experiments, flow-through uptake in continuously stirred batch reactors, and microvolume additions directly to the ribbon.

    TIMS analysis: A side-by-side comparison of traditional bead-loaded materials and thin film-loaded samples will be performed at SRNL. The analysis will be performed using a reference plutonium sample, examining both the isotopic ratios and the total counts obtained for each sample. These studies will allow determination of any signal enhancement created by the alternative loading method and potentially indicate reduction of sample loss due to explosive decompression.

    Ribbon geometry: After optimal thin film formation and loading conditions have been determined, the research will focus on fabrication and testing of ribbons with novel rhenium physical geometry. The varying geometries may result in greater ionization of plutonium during the TIMS analysis.

    The primary deliverable from this project will be a method for producing polymer thin film-coated rhenium ribbons to improve TIMS analyses. The knowledge gained from these studies has the potential to increase the sensitivity of TIMS analyses by one or more orders of magnitude. Increasing the sensitivity of TIMS analyses may lead to enhanced ability to detect proliferant isotopes. The results from this project will be disseminated to the scientific community in the form of progress reports to NNSA, technical presentations at national meetings, and publication of the results in peer-reviewed literature.

  • Examination of Actinide Chemistry at Solid-Water Interfaces to Support Advanced Actinide Separations
    abstract coming soon
  • SRR Technical Support Provided
    abstract coming soon
  • SRR Technical Support Provided by Clemson University
    abstract coming soon
  • Clemson University Nuclear Engineering and Radiological Sciences Scholarship Program
    Scholarships sponsored by the Nuclear Regulatory Commission support fifteen undergraduate students per year at Clemson University. Scholarship students will be required to pursue the new Nuclear Engineering and Radiological Science (NERS) minor. As part of the minor, scholars will be encouraged to participate in a summer internship with an outside partner such as a national laboratory, utility, or regulatory agency. This will provide scholars with an opportunity both to interact with a practicing professional and to apply their academic knowledge in the nuclear sector. The NERS minor is a new undergraduate minor built on thirty years of experience of the graduate only Nuclear Environmental Engineering and Science academic program housed within the department of Environmental Engineering and Earth Science. The minor will enrich engineering and science undergraduates with knowledge on nuclear specific topics, including introduction to nuclear engineering, environmental health physics, radioactive waste management, environmental risk assessment, the nuclear fuel cycle, radiation detection and measurement. The scholarship program is expected to attract the top students from Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Materials Science and Engineering, Mechanical Engineering, and Physics, for participation in the NERS minor.
  • Stabilization of PU Surface Complexes on Mineral Colloids by Natural Organic Matter
    abstract coming soon
  • Radiation Detection Research and Development in Accordance with SOW No. G-SOW-A-01422, REV. 0
    Clemson University will assist in material research and development and conduct radiation detection testing under this contract. This work will use nanoscale neutron conversion materials and analyze the response to neutron radiation for development of radiation detector technology. Proportional detectors are a common type of gas-filled radiation detection device utilized in the nuclear industry because they are robust and inexpensive. Boron-lined proportional counters have been considered as a potential next generation neutron detector. Scintillation based detectors are desirable for many radiation detection applications (portal and border monitoring, safeguards verification, contamination detection and monitoring). The development of next generation scintillators will require improved detection sensitivity for weak gamma ray sources, and fast and thermal neutron identification.
  • MDOA and TEA Resins Development
    Clemson University will generate two batches of special technetium extraction resins – one incorporating methyldioctylamine (MDOA) and the other incorporating triethylamine (TEA). The MDOA and TEA resins will be utilized in a series of technetium extraction/retention studies performed at the Savannah River Laboratory. These studies will be carried out as part of a Laboratory Directed Research and Development project.
  • Robust Extractive Scintillating Resin and Adsorptive Membranes for Plutonium Isotopic Analyses of Aqueous Media
    The objective of this research is to advance scientific understanding in the development of high-selectivity sensor materials and high-sensitivity sensors for ultra-trace-level isotopic analysis of plutonium in aqueous media. The capability brought about by this research program to concentrate and detect plutonium in natural water with a single material would be a powerful nuclear forensics tool that is currently not available. Scope: 1. Design, synthesize, and characterize a new class of extractive scintillator resins that incorporate covalently bound scintillator molecules and selective ligands for simultaneous concentration and detection of plutonium in aqueous media. We will prepare two resin platforms for comparative testing: one incorporates ligands continuously throughout the resin matrix and the other isolates ligands within a polymer nanolayer adjacent to the resin-solution interface. The second type of resin will be prepared by grafting ligand-rich nanolayers from the resin surface using surface-initiated atom transfer radical polymerization. Building off our prior experience developing extractive scintillators for other radionuclides, the focus of this grant will be on the identification and testing of ligands for the selective removal of plutonium from near-neutral waters. By positioning the extractive scintillator in front of a photomultiplier tube or other light sensitive device, the plutonium sorbed onto the resin can be quantified during the loading period. Subsequent to the plutonium loading, the sorbed radioactivity can be eluted from the column and prepared by nanofiltration for alpha spectroscopy. In the case where the ligand is not sufficiently selective for plutonium, the radioactivity can be eluted sequentially and the fractions prepared for alpha spectroscopy by nanofiltration. Design, synthesize, and characterize a new class of adsorptive membranes for the selective concentration of plutonium. Adsorptive membranes offer the possibility of higher solution flow rates combined with the possibility to perform direct alpha spectroscopy on the plutonium-loaded membranes. These membranes will be prepared with either the ligand bound or unbound to an ultrathin surface coating on an ultrafiltration support. A third strategy will attach the ligand to a polymer that is then suspended in solution prior to ultrafiltration. In all cases the end result is a membrane with a nearly ideal surface for direct isotopic determination via alpha spectroscopy
  • Stabilization of Pu Surface Complexes on Mineral Colloids by Natural Organic Matter Statement of Work
    abstract coming soon
  • Two-Day Workshop at SRS
    This proposed project will continue to refine lecture material for an introductory multidisciplinary course for junior and senior undergraduate students and graduate students in the areas of Advanced Nuclear Separation Science and Issues related to Safeguards and Non-proliferation in the South Carolina region. The material developed will be used in a two-day workshop held at SRNL and will be implemented in nuclear fuel cycle and nuclear forensics courses taught at Clemson University. The proposed work will integrate resources at Clemson University and Savannah River National Laboratory to include lectures from experts from national laboratories and DOE agencies. This proposal will also benefit other HCD thrust areas including safeguards internships, short courses, knowledge retention and mid-career transition. The proposed multidisciplinary course material integrates policy, technical and scientific topics relevant to the verification and monitoring of nuclear facilities under the NPT and Additional Protocol (INFCIRC-540). Current nuclear-related courses will include: guest lecturers from NL experts in the areas of separation science, safeguards, and international treaties; hands-on experience targeting concepts and approaches for the verification of separation facilities; and, visits to operational facilities such as MOX, H-Canyon, and Westinghouse fuel fabrication facility. Relevant topics and specific lectures will be identified and developed in consultation with NNSA HCD program managers and other experts on the field as required. A multi-step approach is proposed to build up the required knowledge, infrastructure and momentum to develop a safeguard curriculum with focus in advances nuclear separation.
  • Reactive Membranes for Rapid Isotopic Analyses of Waterborne Special Nuclear Material
    This multidisciplinary research effort will develop the basic science associated with a new class of reactive membranes for rapid isotopic quantification of waterborne special nuclear material (SNM). Comprehensive and systematic studies will be done to test the hypothesis that reactive membranes with U and Pu selective ligands will enable the rapid concentration of samples from solution and simultaneously prepare substrates for direct isotopic analyses and, after addition of scintillating quantum dot coatings, quantitative elemental analyses. The work will provide a deep understanding of the roles of membrane type, degree of SNM loading, and quantum dot characteristics and coating thickness on the SNM analyses. The analytical methods utilizing the proposed materials will be simple and will allow measurements to be conducted in the field. Thus, the ultimate outcome will be a fast and reliable method to conduct forensics of debris from a nuclear event by integrating the science of reactive membranes for SNM isolation and concentration with accurate nuclear spectroscopy for activity and isotope quantification. The proposed rapid radiometric nuclear forensics tool currently is not available, even for laboratory analyses.
  • Reliable Nuclear Materials Identification Technology from Spectroscopy Data
    The project will be focused on development of new algorithms and instruments for radioactive materials detection in order to increase control of the radioactive materials storage and to prevent their illicit shipment. The research is motivated by the quest for reliable means for early detection of these threats. The goal of suggested research is to develop low-cost neutron/gamma-ray detection systems for monitoring of radiological and nuclear threats. It will include development of the new algorithms for treating full spectra signals and developing new scintillator detectors. The approach will give the possibility of precise near real time identification of radioactive materials.
  • R&D of the Liquid Sampling, Atmospheric Pressure Glow Discharge (LS-APGD) with Respect to Uranium Sensitivity and Isotope Ratio Accuracy
    Clemson University shall collaborate with the Pacific Northwest National Laboratory (PNNL) in support of the project entitled “Feasibility of Fieldability Issues for Atomic Mass Spectrometry”, funded through the NA-24 program. Dr. Marcus at Clemson University has expertise in the design, assembly, and operation of liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization sources, which hold promise in applications that are the topic of said project. PNNL will provide hardware, supporting documentation, and research support both in the Clemson University laboratories and on-site at the PNNL.
  • Technetium Extraction/Retention Studies (NSCB00008)
    Clemson University will generate one batch of special technetium extraction resin. Polymethacrylate-based solid phase (PMA) will be prepared, and then functionalized with methyldioctylamine (MDOA). The MDOA resin will be utilized in a series of technetium extraction/retention studies performed at the Savannah River Laboratory (SRNL). These studies will be carried out as part of a Laboratory Directed Research and Development (LDRD) project.
  • Coupling Experiments and Atomic Modeling to Characterize Actinide Oxides in Support of Nuclear Forensics
    Dr. Lindsay Shuller-Nickles’ experience in nuclear materials science will be applied to technical nuclear forensics as she develops a research program integrating computational and experimental techniques for characterizing actinide oxides. Research objectives include (i) identification of microstructural changes during conversion of U and Pu metal to oxides for storage, (ii) quantification of I2 diffusion through solid matrices to aid atmospheric monitoring near reprocessing facilities, and (iii) characterization of U and Pu associated with particulates found in post-detonation melt glass. The proposed research expands on Clemson University’s existing collaborations with nuclear forensics experts at Savannah River National Laboratory (SRNL) and Lawrence Livermore National Laboratory (LLNL), which will ensure an applicable program. Dr. Shuller-Nickles is an assistant professor in the Nuclear Environmental Engineering and Science program housed within Environmental Engineering and Earth Sciences Department at Clemson University. Her major teaching efforts are on materials production and disposal throughout the nuclear fuel cycle. She will expand this course to include nuclear forensics applications, particularly safeguarding and monitoring of nuclear materials. Additional outreach objectives include a nuclear summer workshop for K-12 educators to expand their knowledge of nuclear science with the intention that participants share this knowledge-base with a broad audience of students.
  • Radionuclide Waste Disposal: Development of Multi-scale Experimental and Modeling Capabilities
  • US NRC Fellowship Grant at Clemson University
    Fellowships are requested to support three graduate students (MS/PhD) per year in nuclear environmental engineering and science (NEES) program within the Environmental Engineering and Earth Sciences Department at Clemson University. Fellowship students will pursue a course of study in either Environmental Health Physics (ABET-ASAC accredited at MS level) or Environmental Radiochemistry. Fellows will conduct their thesis/dissertation research in collaboration with an outside partner such as a national laboratory, utility, or regulatory agency. This will provide fellows with an opportunity both to interact with a practicing professional and to conduct research that contributes to the solution of a contemporary technical issue in the nuclear sector.
  • Probabilistic Risk Assessment Faculty Development in Nuclear Engineering and Science Program at Clemson University

    This proposal seeks start-up package funds and partial salary for a new tenure-track faculty position in level 3 probabilistic risk assessment (PRA) and/or radioecology within the Nuclear Environmental Engineering and Science (NEES) program at Clemson University. This faculty member would complement existing expertise in environmental radiochemistry and environmental health physics (EHP) while bringing skills that would allow the NEES faculty to tap into research funds that are currently beyond their reach. The ideal faculty candidate will have expertise in level 3 PRA which provides insight regarding the risks and consequences of nuclear related activities such as power plant production, waste disposal, and site remediation. The primary research activities of the ideal candidate will be to examine the transport, effects, and risks from environmental releases of radionuclides to human health and biota. R. A. Fjeld (Emeritus NEES faculty), N. A. Eisenberg (Emeritus NRC employee), and K. L. Compton (Ph.D. EEES (NEES) and current NRC employee) co-authored a textbook entitled: Quantitative Environmental Risk Analysis for Human Health, in 2007 which is just one of two textbooks in the field of level 3 PRA. Dr. Fjeld retired in 2009 and we are looking to fill this new faculty position with someone with similar expertise. There is a recognized worldwide need for educational programs focusing on nuclear science and technology due to the aging nuclear workforce and declining nuclear educational programs. European communities have recognized the need for similar research and educational programs and as a result have developed the Strategy for Allied Radioecology (STAR) Alliance (http://www.star-radioecology.org/). Similar efforts are underway in the United States through the National Center for Radioecology (NCoRE) managed by the Savannah River National Lab (SRNL) of which Clemson University is a key partner. With this grant the new faculty member will have the tools and support needed to develop a world-class research and educational program given the existing strengths in the current NEES program, the location of NCoRE close to Clemson University, and existing collaborations between current NEES faculty and SRNL scientists.


NEESRWM Director: Dr. Tim DeVol
Environmental Engineering and Earth Sciences | 342 Computer Court, Anderson, SC 29625 | (864) 656-1014