Dr. Brienne Seiner has been a research scientist at Pacific Northwest National Laboratory since 2010. She is a team lead within the Chemistry of Nuclear Materials group in PNNL’s National Security Directorate (NSD). She is a trained radiochemist with experience in inorganic complexation, organic synthesis, chemical separations, and isotope production. Her work at PNNL has focused on R&D projects in areas of nuclear non-proliferation detection and analysis in multiple sponsor spaces. She has served as the nuclear security S&T deputy portfolio manager in charge of internal capability coordination and communication related to PNNL’s work in nuclear science and is also the current mission focus area lead for nuclear science for NSD. In this role she works closely with multiple NSD sectors, sub-sectors, and line managers to develop strategy in new and existing areas, as well as help manage proposal calls and internal investments. Dr. Seiner is also the PNNL program area manager for the material production and detection portfolio within the National Nuclear Security Administration’s Office of Defense Nuclear Nonproliferation R&D (NA-22) program office. 

Dr. Schwantes is a senior scientist at PNNL with over 20 years of experience as a radiochemist working in areas related to the environment, super-heavy element chemistry and physics, astrophysical nucleosynthesis, science-based stockpile stewardship, and nuclear forensics. This work has included the development of novel methods for extracting and detecting radionuclides from fresh and marine waters, integrating these methods with compact, autonomous, in situ, detection systems developed in-house. He has authored or coauthored nearly 70 peer-reviewed journal articles, was part of the confirmatory team for the discovery of element 111 (subsequently named roentgenium), and led a team of researchers in 2009 that identified the oldest known reactor-produced plutonium in the world.

Dr. Gregg Lumetta leads PNNL's Actinide Science Team and serves as the principal investigator for the Nuclear Process Science Initiative DOE project, Fundamental Understanding of Nucleation Processes to Assess Solution Stability and Phase Growth and Genesis, seeking to develop new methods for separating actinides from irradiated nuclear fuel. He also plays a lead technical role in preparing plutonium oxide specimens for nuclear forensics applications. Dr. Lumetta has been responsible for planning and executing various applied and fundamental research projects related to radiochemical separations processes. He serves as a member of Technical Expert Group for DOE's Office of Environmental Management and is focus area lead for the Transuranic Recycle Technology Focus Area of the Sustainable Nuclear Power Initiative at PNNL.  Additionally, he served as PNNL technical lead for the Department of Homeland Security Threat Awareness and Characterization Thrust Area. 

Dr. Jaehun Chun currently serves as the Nuclear Process Science Initiative Principal Investigator of LDRD Project Correlation of Colloidal Interactions and Macroscopic Rheology in Concentrated Electrolyte Solutions. Since joining Pacific Northwest National Laboratory in 2008, Dr. Chun has been performing and leading research in various theoretical and experimental aspects of ‘structured’ fluids: suspension rheology, granular materials, and multiphase flows. He also has been working on related areas such as millimeter wave rheometry and the prediction of magnetic permeability of ferrites. He holds a bachelor's degree in chemical engineering from Yonsei University (Korea), a M.S. from KAIST (Korea) in electrophoresis/hydrodynamic fractionation, a Ph.D. degree in colloidal physics and physicochemical hydrodynamics from Cornell University, and a Postdoctoral Fellow from Princeton University in electrohy drodynamics and dispersion forces.

Dr. David Abrecht is the Nuclear Process Science Initiative Principal Investigator of the LDRD Project Development of Phase Field Modeling to Predict Morphologies of Plutonium Oxalate. He joined Pacific Northwest National Laboratory in April 2013, initially as a postdoctoral fellow in the National Technical Nuclear Forensics program. He was promoted to staff scientist the following year. At PNNL, his work has focused on research and development in chemical process modeling and laboratory materials characterization for the development of nuclear forensic signatures. Dr. Abrecht’s noteworthy accomplishments include development of Pitzer-based models of the historic Hanford Site spent fuel reprocessing stages. He used the models to investigate the dependence of product materials properties on process conditions, and he conducted laboratory analysis of surrogate materials for validation. He also investigated and developed a signal filter based on Kalman filtering mathematics for use in Mössbauer spectrometry. In the years prior to joining PNNL, Dr. Abrecht performed graduate student research and taught courses at the California Institute of Technology. He earned his master’s and doctorate degrees in chemical engineering at Caltech, and holds bachelor’s degrees in paper science and engineering and chemical engineering from North Carolina State University.

Dr. Amanda Casella is the Nuclear Process Science Initiative Principal Investigator of LDRD Project Interfacial Diffusion and Crud Formation at the Liquid:Liquid Interface of Solvent Extraction Processes. She holds a B.S. in chemical engineering, a M.S. and Ph.D. in nuclear engineering from the University of Missouri. Dr. Casella has experience, expertise, and capabilities in the following areas:

• Pu oxide processing and metal conversion
• Solvent extraction relative to nuclear fuel processing utilizing batch methods, centrifugal contactors, and mixer-settlers
• Modeling radiolysis effects with specific relation to research in nuclear used fuel dissolution kinetics
• Nuclear used fuel wasteform corrosion
• Dosimetry modeling at the fuel-water interface
• Spectroscopic techniques (UV, visible, NIR, Raman)
• Kinetic phosphoresce analysis, isothermal titration calorimetery, and gas chromatography-mass spectrometry
• Thermal analysis and fission gas release of irradiated nuclear fuels (LFA, DSC, TG/DTA-MS)

Dr. Richard Clark is currently the Nuclear Process Science Initiative Principal Investigator for LDRD Project Modeling the Interfacial Effects, Partitioning, and Production Routes of Epsilon Particles in Uranium Oxide. For this project, he will lead the development of a new mass spectrometry instrument based on the use of NF3 to fluorinate, volatilize, and separate components of samples. Dr. Clark joined the Pacific Northwest National Laboratory in 2014 as a scientist within the Nuclear Process Signatures Group and a postdoctoral fellow the field of Chemistry (Nuclear Forensics - Mass Spectrometry).

Dr. Greg Kimmel is the Nuclear Process Science Initiative Principal Investigator of the LDRD Project radAFM: Coupled Radiation Source/Liquid-cell AFM to Study Radiation-induced Interfacial Processes. Dr. Kimmel is interested in the chemistry and physics occurring at metal and metal oxide surfaces and in the structure and reactivity of aqueous systems on metals, oxides and nano-engineered materials. He has investigated the thermal and photochemical reactions of small molecules such as O₂, H₂O and CO on transition metal oxides using ultrahigh vacuum surface science techniques. He has also investigated the non-thermal, electron-stimulated reactions in thin amorphous solid water (ASW) and crystalline ice (CI) films. The use of model systems provides insight into the transport of energetic and reactive species, adsorbate geometries, the spatial profile of reactions in the films, and other key properties of these systems.

Dr. Steven R. Spurgeon is the principal investigator of the NPSI project, Damage Mechanisms and Defect Formation in Irradiated Model Systems. He joined PNNL in 2015 and became a staff member in 2017. His research is focused on the structure, properties, and behavior of nanoscale materials systems for energy, data storage, and next-generation electronics. Dr. Spurgeon is an expert in the characterization of functional materials using scanning transmission electron microscopy, electron energy loss spectroscopy, and image simulations. His research employs complementary, multidimensional analysis techniques and theory calculations to generate deep insight into the behavior of complex materials systems.

Barbara Beller serves as the Nuclear Process Science Initiative’s Project Coordinator, a role she has held since November 2016. Ms. Beller works closely with the NPSI Lead, performing a wide range of administrative and planning functions to help advance initiative objectives. She also extends this support to the initiative’s leadership team and research staff. Her previous experience at PNNL includes more than six years in the Business Systems Directorate, where she provided expertise to a contracts group, business offices and several departments, and delivered dependable, timely, quality service through reports, analysis, training and advice. Ms. Beller holds a bachelor’s degree in Business Administration, with a major in Accounting, from Washington State University.