• Chair, Materials Science and Engineering
  • Associate Professor, Metallurgical Engineering
  • Associated Faculty for Nuclear Engineering
  • Chair of Materials Science & Engineering, Materials Science and Engineering
  • Adjunct Professor, Civil And Environmental Engin
  • Professor, Metallurgical Engineering

Research Statement

Overview of My Research

Molten salts play a major role in a number of metallurgical separations processes, including aluminum and titanium processing.  I am actively working to support their applications in advanced nuclear energy systems.  In particular, I am interested in the uranium-plutonium metal fuel based Integral Fast Reactor (IFR) as well as molten salt fueled and/or cooled nuclear reactors.   Molten salts are used by the IFR as an electrolyte in electrochemical cells called electrorefiners that separate uranium or uranium/plutonium from spent nuclear fuel.  The recovered actinides are in the metallic state and can readily be re-cast into new fuel rods for these reactors.  In molten salt fueled reactors, uranium, thorium, or plutonium is dissolved in either a fluoride or chloride molten salt. These reactors can operate safely at low pressure and can be designed to very efficiently fission actinides in order to achieve sustainable use of energy resources while minimizing the amount of nuclear waste generated.  Our group specializes in studying electrochemical and pyrochemical processes with these salts.  We are developing technology to monitor the composition of the salts in real time.  We are developing conceptual safeguards approaches to virtually eliminate the potential for diversion of plutonium from nuclear fuel processing facilities.  And we are developing compact, durable waste forms to enable safe permanent disposal of the waste from nuclear reactors.

Additionally, we are applying what we have learned from nuclear-based molten salt systems to support the use of molten salts as heat transfer/storage fluids in concentrating solar power (CSP) plants.  We have recently published research on the electrochemical effect of adding magnesium metal to MgCl2-NaCl-KCl salt mixtures (https://authors.elsevier.com/a/1ZbuR3In-93NRd). This will soon be followed by a publication on the effect of Mg addition on corrosion of other metals.


Research Keywords

  • pyroprocessing
  • molten salt
  • electrochemical processing
  • Nuclear Fuel Reprocessing


  • M.F. Simpson (speaker), Justin McAllister, Ethan Hamilton, and Matthew Newton, “Design and Operation of a System for the Preparation of a Molten Chloride Nuclear Fuel Salt,” Annual Meeting of the American Institute of Chemical Engineers, Orlando, Nov 9-14, 2019. Other, Presented, 11/01/2019.
  • M.F. Simpson (speaker), Suhee Choi, Olivia Dale, Mario Gonzalez, and Nicole Orabona, “Effect of Dissolved Mg on the Electrochemistry of Molten MgCl2-NaCl-KCl,” Global 2019, Seattle, September 26, 2019. Other, Presented, 09/2019.
  • M.F. Simpson (speaker), Prashant Bagri, Suhee Choi, Olivia Dale, Huan Zhang, Manish Wasnik, Devin Rappleye, and Nicole Orabona, “Basic Molten Salt Research Needs to Support Development of Liquid Fueled Generation-IV Nuclear Reactors,” Fall Meeting of the American Chemical Society, San Diego, August 28, 2019. Other, Presented, 08/2019.
  • M.F. Simpson (speaker), Emma Faulkner, Matt Jackson, and Marisa Monreal, “Analysis and Effect of Residual Water on Chemistry of Molten CaCl2 used for Plutonium Processing,” Actinide Separations Conference, Kingsport, May 2019. Other, Presented, 05/2019.
  • M.F. Simpson (speaker), S. Choi, N. Orabona, and O. Dale; “Effect of Purification Procedures on Electrochemistry of Molten MgCl2-KCl-NaCl”, Annual TMS Meeting, San Antonio, March 12, 2019. Other, Presented, 03/2019.
  • M.F. Simpson (speaker), M. Wasnik*, K. Carlson, L. Gardner*, and P. Bagri*, "Development of Dechlorinated Salt Wasteforms using H-Y Zeolite," Global 2017, Seoul, September 24-29, 2017. Conference Paper, Presented, 09/28/2017.
  • M.F. Simpson (speaker), C. Zhang*, D. Rappleye*, and Z. Wang*, “Optimized Voltammetry Methods for Measuring Concentration of Multiple Rare Earths in Molten LiCl-KCl,” Annual TMS Meeting, San Diego, March 1, 2017. Conference Paper, Presented, 03/01/2017.
  • M.F. Simpson (speaker); “Examples of the Application of Redox Control for Pyroprocessing Spent Nuclear Fuel in Molten LiCl-KCl;” American Institute of Chemical Engineers Annual Meeting, San Francisco, November 16, 2016. Conference Paper, Presented, 11/16/2016.
  • D. Rappleye*, D. Horvath*, C. Zhang*, Z. Wang*, and M.F. Simpson (speaker); “Methods for Determining the Working Electrode Interfacial Area for Electroanalytical Measurements of Metal Ions in Molten LiCl-KCl;” PRiME 2016, Honolulu, October 3, 2016. Conference Paper, Presented, 10/03/2016.
  • D. Rappleye*, C. Zhang*, Z. Wang*, and M.F. Simpson (speaker); “Development of Advanced Voltammetry Methods for Measuring Concentration of Actinides and Lanthanides in Electrorefiner Salt;” International Pyroprocessing Research Conference, Jeju, Korea, September 23, 2016. Conference Paper, Presented, 09/22/2016.
  • D. Rappleye* and M.F. Simpson (speaker); “Electrochemical Concentration Measurements for Online Monitoring of Used Nuclear Fuel;” American Institute of Chemical Engineers Annual Meeting, Salt Lake City, November 11, 2015. Conference Paper, Presented, 11/11/2015.
  • M.F. Simpson, “What is pyroprocessing, and how can it be applied to CANDU used fuel?” Future Options for Managing Irradiated CANDU Fuel Workshop, Toronto, January 23, 2015. Invited Talk/Keynote, Presented, 01/23/2015.
  • M.F. Simpson, “Process Monitoring and Safeguards of Nuclear Processes involving Molten Salts,” Savannah River National Laboratory Director’s Colloquium, January 8, 2015. Invited Talk/Keynote, Presented, 01/08/2015.
  • M.F. Simpson, “Overview of the Pyrochemical Processing of Spent from from EBR-II,” Seoul National University, December 31, 2014. Invited Talk/Keynote, Presented, 12/31/2014.
  • M.F. Simpson, “Electrochemical Separations Processes for Molten Salt Mixtures,” Seoul National University, December 30, 2014. Invited Talk/Keynote, Presented, 12/30/2014.
  • M.F. Simpson, "Prospects for Safeguarding Pyroprocessing," 5th International Pyroprocessing Research Conference, Idaho Falls, October 21, 2014. Conference Paper, Presented, 10/21/2014.
  • M.F. Simpson, “Striving for Chemical Process Innovation to Enable Closure of the Nuclear Fuel Cycle,” University of Nevada at Reno, Department of Chemical and Materials Engineering Seminar, October 14, 2014. Invited Talk/Keynote, Presented, 10/14/2014.
  • M.F. Simpson, D. Rappleye, E.D. Blandford, and H. Garcia; "Signature Based Safeguards Alternative to Nuclear Material Accountancy;" INMM Annual Meeting, Atlanta, July 20-24, 2014. Conference Paper, Presented, 07/24/2014.
  • M.F. Simpson, "Prospects for Large-Scale Implementation of Pyroprocessing to Close the Nuclear Fuel Cycle;" 29th KAIF/KNS Annual Conference, Busan, South Korea, April 18, 2014. Conference Paper, Presented, 04/18/2014.

Research Groups

  • Nora Alnajjar, Graduate Student. Metallurgical Engineering. 01/01/2018 - 01/01/2019.
  • Emma Faulkner, Graduate Student. Metallurgical Engineering. 01/01/2018 - present.
  • Gregory Strader, Undergraduate Student. Metallurgical Engineering. 09/2016 - 05/2017.
  • Manish Wasnik, Graduate Student. Metallurgical Engineering. 08/15/2016 - present.
  • Silvia Padilla, Undergraduate Student. Metallurgical Engineering. 05/15/2016 - 05/15/2018.
  • Matthew Newton, Undergraduate Student. Metallurgical Engineering. 05/15/2016 - present.
  • Parker Okabe, Graduate Student. Nuclear Engineering. 08/17/2015 - present.
  • Shannon Adams, Graduate Student. Metallurgical Engineering. 08/10/2015 - 06/01/2017.
  • Chao Zhang, Graduate Student. Metallurgical Engineering. 07/01/2015 - present.
  • David Horvath, Graduate Student. Metallurgical Engineering. 01/05/2015 - 01/30/2019.
  • Arielle DeJesus, Undergraduate Student. Metallurgical Engineering. 08/19/2014 - 05/15/2015.
  • Alieksia Minko, Graduate Student. Nuclear Engineering. 08/2014 - 09/2016.
  • Adam Burak, Graduate Student. Metallurgical Engineering. 08/2014 - 03/2019.
  • Mario Gonzalez, Undergraduate Student. Metallurgical Engineering. 05/20/2014 - 03/01/2018.
  • Lauryn Hansen, Undergraduate Student. Metallurgical Engineering. 05/20/2014 - 05/15/2016.
  • Milan Stika, Graduate Student. Metallurgical Engineering. 01/06/2014 - 08/15/2017.
  • Prashant Bagri, Graduate Student. Metallurgical Engineering. 01/06/2014 - 11/01/2017.
  • Devin Rappleye, Graduate Student. Metallurgical Engineering. 08/15/2013 - 06/01/2016.
  • Avi Jurovitzki, Graduate Student. Metallurgical Engineering. 01/05/2013 - 01/30/2015.

Other Profile Data


  • L. Gardner & M. Wasnik, B. Riley, M. Simpson, K. Carlson (2020). Effect of Reduced Dehalogenation on the Performance of Y Zeolite-Based Sintered Waste Forms. Journal of Nuclear Materials. Vol. 545. Published, 12/24/2020.
  • David Horvath, Olivia Dale & Michael Simpson (2019). Electrochemical Response of Metal Alloys to Oxygen Gas Bubbling in Molten LiCl-Li2O Melt. Journal of Radioanalytical and Nuclear Chemistry. Published, 11/07/2019.
  • Wasnik M., Grant A., Carlson K. & Simpson M. (2019). Dechlorination of molten chloride waste salt from electrorefining via ion-exchange using pelletized ultra-stable H-Y zeolite in a fluidized particle reactor. Journal of Radioanalytical and Nuclear Chemistry. Vol. 320, 309-322. Published, 05/15/2019.
  • Neil Taylor & Nora Alnajjar, Josh Jarrell, Michael Simpson, Thomas Blue, Lei Cao (2019). Isotopic Concentration of Uranium from Alpha Spectrum of Electrodeposited Source on 4H-SiC Detector at 500oC. Journal of Radioanalytical and Nuclear Chemistry. Vol. 320, 441-449. Published, 03/2019.
  • Wasnik M., Livingston T., Carlson K. & Simpson M. (2019). Kinetics of Dechlorination of Molten Chloride Salt Using Protonated Ultrastable y Zeolite. Industrial and Engineering Chemistry Research. Published, 01/01/2019.
  • Chao Zhang & J. Wallace*, and M.F. Simpson (2018). Electrochemical measurement of high concentrations of UCl3 and GdCl3 in molten LiCl-KCl eutectic. Electrochemical Acta. Vol. 280. Published, 09/2018.
  • Levi Gardner & B.J. Riley, C. Elliott*, M. Simpson, and K. Carlson (2018). Viscosities and Working Region Predictions for Bismuth Aluminoborosilicate Glasses. Journal of Applied Glass Science. Vol. 10. Published, 09/2018.
  • Joshua Jarrell & Milan Stika*, Michael Simpson, Thomas E. Blue, and Lei R. Cao (2018). 4H-SiC Alpha Spectrometry for Nuclear Forensics with Electrodeposited Sources. Journal of Radioanalytical and Nuclear Chemistry. Vol. 318. Published, 08/2018.
  • Mario Gonzalez & A. Burak*, S. Guo, and M.F. Simpson (2018). Identification, measurement, and mitigation of key impurities in LiCl-Li2O used for direct electrolytic reduction of UO2. Journal Nuclear Materials. Vol. 510. Published, 08/2018.
  • S. Adams & M.F. Simpson (2017). Simulated Response to process abnormalities during spent fuel electrorefining. Annals of Nuclear Energy. Vol. 110, 1002-1009. Published, 12/2017.
  • M. Wasnik & K. Carlson and M.F. Simpson (2017). Waste Minimization of Electrorefiner Waste Salt via Dechlorination: A New Approach. Proceedings of the Winter Meeting of the American Nuclear Society. Published, 11/2017.
  • C. Zhang & M.F. Simpson (2017). Electrorefiner Salt Analytes Concentration Monitoring Through Voltammetric Methods. Proceedings of the Winter Meeting of the American Nuclear Society. Published, 11/2017.
  • M. Wasnik & L. Gardner, K. Carlson, and M. Simpson (2017). Electrorefiner Salt Dechlorination in Ultra-Stable HY Zeolite. Proceedings of Global 2017. Published, 09/2017.
  • P. Bagri and M.F. Simpson, “Activity Coefficient of Gadolinium(III) Chloride in Molten LiCl-KCl Eutectic Salt and its Dependence on Cesium Chloride Concentration using EMF Measurements,” Journal of the Electrochemical Society, 164 (8) H5299-H5307 (2017); doi: 10.1149/2.0441708jes. Published, 07/2017.
  • C. Zhang & M.F. Simpson (2017). Density of Molten Salt Mixtures of Eutectic LiCl-KCl containing UCl3, CeCl3, or LaCl3. Journal of Nuclear Fuel Cycle and Waste Technology. Vol. 15. Published, 06/2017.
  • P. Bagri, C. Zhang, and M.F. Simpson, “Galvanic reduction of uranium(III) chloride from LiCl-KCl eutectic salt using gadolinium metal,” Journal of Nuclear Materials, vol. 493 (2017) 120-123. Published, 06/2017.
  • M. Wasnik & M.F. Simpson (2017). Ion Exchange of LiCl-KCl in H-Y Zeolite for Dechlorination of Electrorefiner Salt Waste Forms. Proceedings of the Annual Meeting of the American Nuclear Society. Published, 06/2017.
  • C. Zhang (2017). Normal Pulse Voltammetry for Real Time Analysis of Electrorefiner Salt with High Concentrations of Analytes. Proceedings of the Annual Meeting of the American Nuclear Society. Published, 06/2017.
  • C. Zhang, D. Rappleye, and M.F. Simpson, “Preliminary Study of Optimization of Normal Pulse Voltammetry for Actinide Measurement in Molten Salt Electrorefiners using LiCl-KCl-UCl3-MgCl2 as a Surrogate Salt,” Journal of the Electrochemical Society, 164 (8) H5218-H5223 (2017). Published, 05/2017.
  • M. Stika, S. Padilla, J. Jarrell, T. Blue, L.R. Cao, and M. Simpson, “Thin-Layer Electrodeposition of Thorium Metal from Molten LiCl-KCl,” Journal of the Electrochemical Society, 164 (8) H5078-H5085 (2017). Published, 05/2017.
  • D. Horvath, D. Rappleye, and M.F. Simpson, “Electrochemical Study of MnCl2 in Molten Eutectic LiCl-KCl;” Journal of Nuclear Materials, vol.493 (2017) 189-199. Published, 05/2017.
  • D. Rappleye and M.F. Simpson; “Application of the Rotating Cylinder Electrode in Molten LiCl-KCl Eutectic Containing Uranium(III)- and Magnesium(II)- Chloride;” Journal of Nuclear Materials, vol. 487, 362-372 (2017). Published, 02/2017.
  • D. Rappleye, M.L. Newton, C. Zhang, and M.F. Simpson; “Electroanaytical Measurements of Binary-Analyte Mixtures in Molten LiCl-KCl Eutectic: Uranium(III)- and Magnesium(II)-Chloride;” Journal of Nuclear Materials, vol. 486, 369-380, 2017. Published, 02/2017.
  • H.E. Garcia, M.F. Simpson, W.-C. Lin, R.B. Carlson, and T.S. Yoo; “Application of Process Monitoring to Anomaly Detection in Nuclear Material Processing Systems via System-centric Event Interpretation of Data from Multiple Sensors of Varying Reliability,” Annals of Nuclear Energy, 103 (2017) 60-73. Published, 01/2017.
  • J. Jarrell, M. Stika, M. Chaiken, M. Simpson, T.E. Blue, and L.R. Cao; "Determination of the Thickness of an Electrodeposited Thorium Film with SiC Alpha Detectors;" Journal of Radioanalytical and Nuclear Chemistry, 2016, doi:10.1007/s10967-016-5093-x. Published, 12/2016.
  • Wang, Zhonghang, Lahti, Erik, Simpson, Michael, Zhang, Jinsuo & Samin, Adib (2016). Estimation of key physical properties for LaCl3 in molten eutectic LiCl–KCl by fitting cyclic voltammetry data to a BET-based electrode reaction kinetics model. Elsevier BV. Vol. 475, 149-155. Published, 01/2016.
  • D. Rappleye and M.F. Simpson; “Electroanalytical Measurements of Binary-Analyte Mixtures in Molten LiCl-KCl Eutectic: Gadolinium(III) and Lanthanum(III) Chloride;” J. of Electrochemical Society, v. 163, n. 9, B507-516, 2016. doi:10.1149/2.1011609jes. Published, 01/2016.
  • D. Rappleye, S.M. Jeong, and M.F. Simpson; “Application of Multivariate Analysis Techniques to Safeguards of the Electrochemical Treatment of Used Nuclear Fuel;” Annals of Nuclear Energy (2015), pp. 265-272. Published, 12/05/2014.
  • H.S. Ji, H.Y. Ryu, E.Y. Choi, S.W. Cho, M.F. Simpson, and S.M. Jeong; “Preparation of NdNi5 using an electrochemical reduction of a NiO-Nd2O3 mixture in molten LiCl;” J. Ind. Eng. Chem. (2014), http://dx.doi.org/10.1016/j.jiec.2014.09.039. Published, 10/05/2014.
  • H.Y. Ryu*, H.S. Ji*, S.M. Jeong, and M.F. Simpson; “Formation of Mg-Li Alloy by Electro-Intercalation of Li+ Ions on a Solid Mg Cathode in an Eutectic LiCl-KCl Salt;” Journal of Chemical Engineering of Japan; vol. 47, n. 9, pp. 750-755, 2014. Published, 09/20/2014.
  • A. Weisberg, R.E. Lakis, M. Simpson, L. Horowitz, and J. Craparo; “Measuring Lanthanide Concentrations in Molten Salt Using Laser-Induced Breakdown Spectroscopy (LIBS);” Applied Spectroscopy, vol. 68, n.9, pp. 937-948, 2014. Published, 08/2014.
  • D.S. Rappleye, M.F. Simpson, R. Cumberland, D. McNelis, and M.S. Yim; “Simulated Real-Time Process Monitoring of a Molten Salt Electrorefiner;” Nuclear Engineering and Design, Volume 273, Pages 75-84, 2014. Published, 07/2014.
  • D. Rappleye, M. Stika, and M.F. Simpson; “Simulated Response of Electrochemical Sensors for Monitoring Molten-Salt Fueled Reactors;” Proceedings of the 2014 INMM Annual Meeting, Atlanta; July 20-24, 2014. Published, 06/09/2014.
  • M.F. Simpson, D. Rappleye, E.D. Blandford, and H. Garcia; “Signature Based Safeguards Alternative to Nuclear Material Accountancy;” Proceedings of the 2014 INMM Annual Meeting, Atlanta; July 20-24, 2014. Published, 06/09/2014.
  • P. Lafreniere, D. Rappleye, M.F. Simpson, and E. Blandford; “Demonstration of Signature-Based Safeguards for Pyroprocessing as Applied to Electrorefining and the Ingot Casting Process;” Nuclear Technology, vol. 189, No. 2, February 2015, pp. 173-185. Published, 02/22/2014.