Chemist
Chemist

Biography

Richard Clark joined Pacific Northwest National Laboratory (PNNL) in 2010 as a graduate research fellow, then went on to teach and gain experience at another national laboratory. Clark returned to PNNL in 2014 and is now a research scientist in the National Security Directorate (NSD).

Clark has experience in radiochemistry related to gaseous fluorinations and separations, thermoluminescence, nuclear material science, nuclear fuel cycle, and microscopy. As a fluorination subject matter expert, Clark has extensive experience with fluorination of actinides using various reagents. In the nuclear fuel cycle, Clark researches signature discovery during several parts of the process. The majority of his work is focused on the production of oxides.

Research Interest

  • Actinide Chemistry
  • Nuclear and Radiochemistry
  • Nuclear Forensics
  • Nuclear Fuel Cycle
  • Nuclear Materials Processing
  • Nuclear Nonproliferation

Education

  • PhD in chemistry, University of Missouri-Columbia
  • BS in chemistry, Brigham Young University-Idaho

Awards and Recognitions

  • PNNL
    • NSD Core Value Award – Collaboration, 2020
    • Pathway to Excellence, 2019
    • National Nuclear Security Administration Joule Award, 2018
  • University of Missouri-Columbia Chemistry Department
    • David E. Troutner Fellowship, 2011
    • American Nuclear Society James R. Vogt Radiochemistry Scholarship, 2009
    • Nuclear Forensics Graduate Fellowship, 2009
  • Brigham Young University-Idaho
    • Idaho Award of Excellence, 2004-2007
    • CRC Press Freshman Chemistry Achievement Award, 2005

Publications

2024

  • Dunn, S.A.; Schwerdt, I.J.; Meier, D.E.; Marks, N.E.; Shaw, T.; Hanson, A.; Sentz, K.; Said, M.; Clark, R.A.; Makovsky, K.A.; Lonergan, J.L.; Gilbert, M., “Morphology and particle size (MaPS) exercise: Testing the applications of image analysis and morphology descriptions for nuclear forensics.” Journal of Radioanalytical and Nuclear Chemistry, 2024, Accepted.
  • McDonald IV, L.W.; Sentz, K.; Hagen, A.; Chung, B.W.; Nizinski, C.A.; Schwerdt, I.J.; Hanson, A.; Donald, S.; Clark, R.; Sjoden, G.; Porter, R.; Athon, M.T.; Tasdizen, T.; Noel, V.; Webb, S.M.; Van Veelen, A.; Hickam, S.M.; Ly, C., “Review of multi-faceted morphologic signatures of actinide process materials for nuclear forensic science.” Journal of Nuclear Materials, 2024, 588, 154779 (1-13).

2023

  • Emerson, H.P.; Sinkov, S.I.; Pearce, C.I.; Cantrell, K.J.; Delegard, C.H.; Snyder, M.M.V.; Thomas, M.-L.; Reilly, D.D.; Buck, E.C.; Sweet, L.E.; Casella, A.J.; Carter, J.C.; Corbey, J.F.; Schwerdt, I.J.; Clark, R.A.; Heller, F.D.; Meier, D.E.; Zavarin, M.; Kersting, A.B.; Freedman, V.L., “Solubility controls on plutonium and americium release in subsurface environments exposed to acidic processing wastes.” Applied Geochemistry, 2023, 153, 105241 (1-13).
  • Gilbert, A.J.; McDonald, B.S.; Kasparek, D.M.; Wittman, R.S.; Gillis, W.C.; Clark, R.A.; Brayfindley, E.; Sweet, L.E., “Quantitative uranium elemental reconstruction with spectral X-ray radiography.” Journal of Applied Physics, 2023, 134, 024902 (1-11).
  • Hainje, C.M.; Nizinski, C.A.; Jackson, S.W.; Clark, R.A.; Heller, F.D.; Schwerdt, I.J.; Buck, E.C.; Meier, D.E.; Hagen, A.R., “Investigation of process history and underlying phenomena associated with the synthesis of plutonium oxides using Vector Quantizing Variational Autoencoder.” Chemometrics and Intelligent Laboratory Systems, 2023, 240, 104909 (1-9).
  • LaCount, M.D.; Meier, D.E.; Ritzmann, A.M.; Muller, S.E.; Clark, R.A.; Buck, E.C.; Abrecht, D.G., “Ab Initio Modeling and Thermodynamics of Hydrated Plutonium Oxalates.” Journal of Nuclear Materials, 2023, 583, 154504 (1-8).
  • Lonergan, J.; Goncharov, V.; Swinhart, M.; Makovsky, K.; Rollog, M.; McNamara, B.; Clark, R.; Cutforth, D.; Armstrong, C.; Guo, X.; Paviet, P., “Thermodynamic investigation of the NaCl- KCl salt system from 25 to 950 °C.” Journal of Molecular Liquids, 2023, 391, 122591 (1-12).

2022

  • Liu, L.; Kruska, K.; Hall, G.B.; Clark, R.A.; Meier, D.E.; Buck, E.C., “Formation and growth of cerium (III) oxalate nanocrystals by liquid-cell transmission electron microscopy.” Scripta Materialia, 2022, 219, 114856 (1-6).
  • McNamara, B.K.; O’Hara, M.J.; Morrison, S.; Soderquist, C.Z.; Clark, R.A.; Carter, R., “Separations of U/Pu and Np/Pu using fluoride volatility.” Journal of Fluorine Chemistry, 2022, 257-258, 109952 (1-10).

2021

  • Pope, T.R.; Stene, R.E.; Guerrero, R.; Clark, R.; Koh, K.; Beck, C.L.; Thomas, M.-L., “Single-use destructive assay for uranium hexafluoride sampling.” Proceedings of the Institute of Nuclear Materials Management Conference, August 23-26, 2021.
  • Walter, E.D; Capan, C.; Casella, A.J.; Carter, J.C.; McNamara, B.K.; Soderquist, C.Z.; Sinkov, S.I.; Clark, R.A.; Heller, F.D.; Sweet, L.E.; Corbey, J.F.; Cho, H., “Measurement of local magnetic fields in actinide tetrafluorides.” The Journal of Chemical Physics, 2021, 154, 211101 (1-5).

2020

  • Clark, R.A.; Conroy, M.A.; Lach, T.G.; Buck, E.C.; Pellegrini, K.L.; McNamara, B.K.; Schwantes, J.M., “Distribution of metallic fission product particles in the cladding liner of spent nuclear fuel.” npj Materials Degradation, 2020, 4(4), 1-9.
  • Kessler, S.H.; Lach, T.G.; Garrett, K.E.; Conroy, M.A.; Abrecht, D.G.; Schwantes, J.M.; Clark, R.A., “Direct Observations of Pd-Te Compound Formation within Noble Metal Inclusions in Spent Nuclear Fuel.” Journal of Nuclear Materials, 2020, 538, 152249 (1-8).
  • McNamara, B.K.; Casella, A.M.; Buck, E.C.; Clark, R.A.; Schwerdt, I.J.; Surbella III, R.G.; McCoy, K.M., “Targeted uranium recovery from complex alloys using fluoride volatility.” Journal of Fluorine Chemistry, 2020, 235, 109539 (1-7).
  • McNamara, B.K.; O’Hara, M.J.; Clark, R.A.; Morrison, S.S.; Soderquist, C.Z.; Scheele, R.D., “Gas- phase molybdenum-99 separation from uranium dioxide by fluoride volatility using nitrogen trifluoride.” RSC Advances, 2020, 10, 3472-3478.
  • Schwantes, J.M.; Bair, J.L.; Buck, E.C.; Devanathan, R.; Kessler, S.H.; Lach, T.G.; Lonergan, J.M.; McNamara, C.J.; Palmer, C.J.; Clark, R.A., “A new non-diffusional gas bubble production route in used nuclear fuel: implications for fission gas release, cladding corrosion, and next generation fuel design.” Physical Chemistry Chemical Physics, 2020, 22, 6086-6099. (Journal cover article)

2019

  • Casella, A.; Carter, J.; Lines, A.; Bello, J.; Bryan, S.; Clark, R.; Corbey, J.; Delegard, C.; Heller, F.; McNamara, B.; Sweet, L., “In stream monitoring of off-gasses from plutonium dioxide fluorination.” Actinide Research Quarterly, 2019, 2, 31-35.
  • Lach, T.G.; Edwards, D.J.; Buck, E.C.; McNamara, B.K.; Schwantes, J.M.; Clark, R.A., “Fission recoil- induced microstructural evolution of the fuel-cladding interface [FCI] in high burnup BWR fuel.” Journal of Nuclear Materials, 2019, 521, 120-125.
  • Palmer, C.P.; Gerez, K.R.; Schwantes, J.M.; Clark, R.A., “Scoping evaluation of trace isotopic ratios within the noble metal-phase as indicators of reactor class.” Progress in Nuclear Energy, 2019, 117, 103059.
  • Pellegrini, K.L.; Soderquist, C.Z.; Shen, S.D.; Krogstad, E.J.; Palmer, C.J.; Gerez, K.R.; Buck, E.C.; Lach, T.G.; Schwantes, J.M.; Clark, R.A., “Chemical and isotopic characterization of noble metal phase from commercial UO2 fuel.” Analytical Chemistry, 2019, 91, 6522-6529.
  • Schwantes, J.M.; Conroy, M.; Lach, T.G.; Lonergan, J.M.; Pellegrini, K.L.; Robertson, J.D.; Clark, R.A., “Changing the rules of the game: Used fuel studies outside of a remote handling facility.” Journal of Radioanalytical and Nuclear Chemistry, 2019, 322, 1267-1272.
  • Schwantes, J.; Reilly, D.; Clark, R.; Perea, D.; Buckner, R.; Pierson, R.; Buck, E.; Cliff, J.; Conroy, M.; Lach, T.; MacFarlan, P.; Clark, S.; Peterson, R.; Robertson, J.D.; Palmer, C.; Palmer, T., “Nuclear materials science at the micron scale.” Actinide Research Quarterly, 2019, 2, 36-39.

2018

  • Palmer, C.J.; Gerez, K.R.; Clark, R.A.; Schwantes, J.M., “Trace isotopic ratios within the noble metal phase as indicators of reactor class.” ANS Transactions, Advances in Nuclear Nonproliferation Technology and Policy. 2018, 119, 949-952.

2016

  • Clark, R.A.; Barinaga, C.J.; McNamara, B.K.; Schwantes, J.M.; Ballou, N.E., “Selective fluorination and separation of metals with NF3 for mass spectrometry.” Journal of Radioanalytical and Nuclear Chemistry, 2016, 307, 1587-1590.
  • Kessler, S.H.; Abrecht, D.G.; Clark, R.A.; Schwantes, J.M., “Vibrational contributions to phase stability in the Mo-Ru system.” Journal of Alloys and Compounds, 2016, 689, 969-976.

2015

  • Clark, R.A.; McNamara, B.K.; Barinaga, C.J.; Peterson, J.M.; Govind, N.; Andersen, A.; Abrecht, D.G.; Schwantes, J.M.; Ballou, N.E., “Electron ionization mass spectrum of tellurium hexafluoride.” Inorganic Chemistry, 2015, 54, 4821-4826.

2013

  • Clark, R.A.; Robertson, J.D.; Schwantes, J.M., “Intrinsic dosimetry: Elemental composition effects on the thermoluminescence of commercial borosilicate glass.” Radiation Measurements, 2013, 59, 270-276.
  • Clark, R.A.; Robertson, J.D.; Walter, E.D.; Miller, S.D.; Schwantes, J.M., “Intrinsic dosimetry of glass containers: A potential interrogation tool for nuclear forensics and waste management.” Journal of Radioanalytical and Nuclear Chemistry, 2013, 296, 663-668.

2012

  • Clark, R.A., Intrinsic dosimetry: Properties and Mechanisms of Thermoluminescence in Commercial Borosilicate Glass. Ph.D. Dissertation, University of Missouri, Columbia, MO, 2012.
  • Schwantes, J.M.; Orton, C.R.; Clark, R.A., “Analysis of a nuclear accident: Fission and activation product releases from the Fukushima Daiichi nuclear facility as remote indicators of source identification, extent of release, and state of damaged spent fuel.” Environmental Science and Technology 2012, 46, 8621-8627.

2010

  • Clark, R.A.; Miller, S.D.; Robertson, J.D.; Gregg, R.A.; Murphy, M.K.; Schwantes, J.M., “Intrinsic dosimetry: A potential new tool for nuclear forensics investigations.” Proceedings of the 51st Annual Institute of Nuclear Materials Management Conference, Baltimore, MD, July 11-15, 2010.