U.S. Department of Energy

Pacific Northwest National Laboratory


Sue Clark - Initiative Lead

Dr. Sue B. Clark is a Battelle Fellow in the PNNL Energy and Environment Directorate and Regents Distinguished Professor of Chemistry with tenure at Washington State University in Pullman. In this joint appointment, she leads a research effort focused on the chemistry and chemical engineering of processing nuclear materials. Her current research areas include chemistry of radioactive waste systems, environmental chemistry, actinide separations, and radioanalytical chemistry. Her research support includes grants and contracts from the U.S. Department of Defense, the U.S. Department of Homeland Security, the U.S. Nuclear Regulatory Commission, and the DOE Office of Science and National Nuclear Security Administration.

Sue Clark
(509) 372-6180
Matt Douglas - Deputy NPSI Lead, Scientist

Dr. Matt Douglas is a research scientist in the Radiochemical Analysis Group within the PNNL National Security Directorate and Deputy Lead for the NPSI. His background is in development of chemical separations to support nuclear materials analysis by radiometric and mass spectrometry means. Dr. Douglas’ work has addressed challenges in safeguards, environmental monitoring, and nuclear forensics. Current interests include streamlining data analysis to more rapidly report final values, timeline reductions in nuclear forensics analysis, and investigation of signatures to support nuclear nonproliferation. From 2011-2013, Dr. Douglas served as a technical advisor within the National Nuclear Security Administration Office of Defense Nuclear Nonproliferation.

Matt Douglas
(509) 375-7372
Reid Peterson - Interfacial Chemistry and Physics Lead

Dr. Reid Peterson has worked largely in the field of waste processing for treatment of high-level waste. Dr. Peterson has an extensive background in managing large research programs and experience in taking projects from inception to pilot-scale proof of concept. Through his experiences at PNNL, the Hanford Tank Waste Treatment and Immobilization Plant (WTP), and Savannah River National Laboratory (SRNL), Dr. Peterson has developed working relationships with key staff across the National Lab complex, including Argonne National Laboratory, Idaho National Engineering Laboratory, Los Alamos National Laboratory, and SRNL, as well as the site contractors for waste processing at both the Savannah River Site and Hanford. Dr. Peterson leads research teams in the areas of separation processes for nuclear applications. Current focus areas include dissolution reaction, cesium removal technologies, and solid/liquid separation techniques.  

Reid Peterson
(509) 375-5386
Jon Schwantes - Chemical Fractionation Lead

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.

Jon Schwantes
(509) 375-7378
Kevin Rosso - Multi-scale Modeling Lead

Dr. Kevin Rosso is a Laboratory Fellow and the Associate Director for the Chemical and Material Science Division, Geochemistry Group. Dr. Rosso joined Pacific Northwest National Laboratory in 1998 and is recognized for his work to creatively address long-standing problems in mineral surface chemistry related to reactivity and electron exchange at the mineral-water interface. Dr. Rosso's current projects include the following: (1) characterizing the kinetics and mechanisms of elementary charge and ion transport processes in redox transformation of iron oxide minerals, (2) predicting molecular-scale electron transfer kinetics in microbially-mediated reduction of bioavailable iron in subsurface environments, (3) studying mechanisms of heterogeneous reduction of contaminant U(VI) and Tc(VII) by Fe(II)-bearing minerals, (4) simulation of coupled charge and ion transport in transition metal oxide electrodes for advanced materials applications, (5) probing mechanisms and kinetics of mineral transformation to metal carbonates for geological carbon sequestration, and (6) studying mechanisms of uptake and retention of uranium in sediments.

Kevin Rosso
(509) 371-6357
Gregg Lumetta - NPSI Project Manager, Engineer

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. 

Gregg Lumetta
(509) 375-5696
Edgar C. Buck - NPSI Project Manager, Scientist

Dr. Edgar C. Buck is currently the Principal Investigator of LDRD Project An In-situ Investigation of gamma-AlOOH Dissolution under High pH Conditions for the Nuclear Process Science Initiative. Additionally, he serves as a Program Manager for the Used Fuel Disposition Project at Pacific Northwest National Laboratory looking at radiolysis effects on spent nuclear fuel. Dr. Buck co-authored a special issue in the MRS Bulletin on actinide spectroscopy and the Chapter on Uranium for the 3rd edition of the Chemistry of the Actinide and Transactinide Elements. He has held other scientific leadership roles over time, including the DARPA projects, nuclear forensics, colloidal migration studies, and the PNNL metal waste form project. Dr. Buck is knowledgeable in the interaction of electron beams with matter, electron and x-ray instrumentation, and materials science with an emphasis on radioactive materials. He has expertise in the long-term behavior of nuclear materials; including oxide spent nuclear fuels, borosilicate glass and ceramic waste forms, radio-colloids, and materials for tritium production. He has also conducted data interpretation for the Hanford Waste Treatment Project intermittently for more than 8 years and worked for the Tritium Readiness Program conducting Post-Irradiation Analysis of target components for more than 7 years.

Edgar C. Buck
(509) 375-5166
Jaehun Chun - NPSI Project Manager, Scientist

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.

Jaehun Chun
(509) 372-6257
Richard Daniel - NPSI Project Manager, Research Scientist

Dr. Daniel Richard is the Nuclear Process Science Initaive Principal Investigator of LDRD Project Particle-Filter Surface Interactions and Dynamics in the Presence of Cross-Flow. He has worked as a Research Scientist for the Pacific Northwest National Laboratory since 2005 and currently serves the Fluid and Computational Engineering Group. Dr. Richard holds a B.S. in chemical engineering Florida Institute of Technology and earned his Ph.D. from the University of Washington.

Richard Daniel
(509) 375-5664
David Abrecht - NPSI Project Manager, Scientist

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.

David Abrecht
(509) 375-7376
Dallas Reilly - NPSI Project Manager, Scientist

Dr. Dallas Reilly serves as the Nuclear Process Science Initiative Principal Investigator for LDRD Project Monitoring Diffusion of Actinide Daughters and Granddaughters in Metals for Chronometer Applications. While working for the Pacific Northwest National Laboratory (PNNL), Dr. Reilly has been involved with multiple projects, including work directly funded by NTNFC and other scope meaningful for the development of technical skills necessary for nuclear forensics. Dr. Reilly participated in the Development of Predictive Signatures project by evaluating and summarizing the previous modeling efforts and has worked to help develop the database of thermodynamic constants and Pitzer parameters necessary to operate the database. He holds a B.A. in chemistry from Carthage College (Kenosha, WI), a Ph.D. in Radiochemistry from the University of Nevada, and a Postdoctoral Research Fellow in the Radiochemical Analysis Group at PNNL. 

Dallas Reilly
(509) 375-7382
Amanda Casella - NPSI Project Manager, Research Engineer

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)
Amanda Casella
(509) 375-5622
Ram Devanathan - NPSI Project Manager, Nuclear Sciences Technical Group Manager

Dr. Ram Devanathan is currently the Nuclear Process Science Initiative Principal Investigator of LDRD Project Ion Implantation and Characterization of Epsilon Metal Phase Formation in Ceria. Additionally serves as the Technical Group Manager for the Reactor Materials and Mechanical Design group. He has more than 25 years of experience in materials research using multiscale computer simulations integrated with materials characterization. Dr. Devanathan serves as Adjunct Research Professor in the School of Mechanical and Materials Engineering at Washington State University. He has mentored postdoctoral researchers, and graduate, undergraduate, and high school students through programs such as Young Women in Science, Science Undergraduate Laboratory Internship (SULI), and the Mickey Leland Fellowship. Dr. Devanathan was selected as a Chair of the 2015 Fall Meeting of the Materials Research Society. He is a Fellow of the American Ceramic Society and Chair Elect of the Richland Section of the American Chemical Society.

Ram Devanathan
(509) 371-6487
Richard Clark - NPSI Project Manager, Scientist

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).

Richard Clark
(509) 375-5582
Sebastien Kerisit - NPSI Project Manager, Scientist

Dr. Sebastien Kerisit is the Nuclear Process Science Initiative Principal Investigator of the LDRD Project Fundamental Insights into Gamma-Radiation Effects at Complex Oxide-Water Interfaces from First Principles Simulations. Dr. Kerisit holds a master's degree in chemistry and a Ph.D. in computational chemistry from the University of Bath, U.K. He is an expert in the development and application of atomistic/molecular simulations techniques and has extensive experience with molecular dynamics, kinetic Monte Carlo, and electronic structure simulations, including rare-event techniques. Dr. Kerisit has developed molecular dynamics and Monte Carlo computer codes including programs to simulate glass corrosion in aqueous conditions and charge transport in crystalline solids.

Sebastien Kerisit
(509) 371-6382
Greg Kimmel - NPSI Project Manager, Scientist

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.

Greg Kimmel
(509) 371-6134
Barbara Beller - Project Coordinator

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.

Barbara Beller
(509) 371-7593
Tim Ledbetter - Communications Specialist

Tim Ledbetter is a communications specialist within PNNL’s Energy and Environment Directorate. He possesses nearly 30 years of experience, spanning from broadcast news to organizational and marketing communications. In addition to providing support to the Nuclear Process Science Initiative, Tim serves as the communications point-of-contact for PNNL’s Control of Complex Systems Initiative and is involved in a wide range of communications and marketing activities for PNNL's power grid and buildings research.

Tim Ledbetter
| Pacific Northwest National Laboratory