Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Thermal dehydration tests of FLiNaK salt for thermal-hydraulic experiments

  • Shuai Che (Department of Nuclear Engineering & Radiological Sciences, University of Michigan) ;
  • Sheng Zhang (Department of Nuclear Engineering & Radiological Sciences, University of Michigan) ;
  • Adam Burak (Department of Nuclear Engineering & Radiological Sciences, University of Michigan) ;
  • Xiaodong Sun (Department of Nuclear Engineering & Radiological Sciences, University of Michigan)
  • Received : 2023.06.29
  • Accepted : 2024.01.24
  • Published : 2024.03.25
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Abstract

Fluoride-salt-cooled High-temperature Reactor (FHR) is a promising nuclear reactor technology. Among many challenges presented by the molten fluoride salts is the corrosion of salt-facing structural components. Higher moisture contents, in the FLiNaK (LiF-NaF-KF, 46.5-11.5-42 mol%) salt, aggravate intergranular corrosion and pitting for the given alloys. Therefore, several thermal dehydration tests of FLiNaK salt were performed with a batch size suitable for thermal-hydraulic experiments. Thermogravimetric Analysis (TGA) was performed for the three constituent fluoride salts individually. Preliminary thermal dehydration plans were then proposed for NaF and KF salts based on the TGA curves. However, the dehydration process may not be required for LiF since its low mass loss (<1.3 wt%). To evaluate the performance of these thermal dehydration plans, a batch-scale salt dehydration test facility was designed and constructed. The preliminary thermal dehydration plans were tested by varying the heating rates, target temperature, and holding time. The sample mass loss data showed that the high temperatures (>500 ℃) were necessary to remove a significant amount of moisture (>1 wt%) from NaF salt, while relatively low temperatures (around 300 ℃) with a long holding time (>10 h) were sufficient to remove most of the moisture from KF salt.

Keywords

Acknowledgement

This research was performed using funding received from the U.S. Department of Energy (DOE) Office of Nuclear Energy's Nuclear Energy University Program (NEUP), award number DE-NE0008977. The authors appreciate the financial support from the DOE NEUP Office. The authors would also like to thank Dr. Russell Bornschein of the University of Michigan, Prof. Minghui Chen and Mr. Yuqi Liu of the University of New Mexico for their valuable commentary and technical support of this work.

References

  1. D.E. Holcomb, G.F. Flanagan, G.T. Mays, et al., Fluoride Salt-Cooled High-Temperature Reactor Technology Development and Demonstration Roadmap, Oak Ridge National Laboratory, 2013,. ORNL/TM-2013/401. 
  2. D. Jiang, D. Zhang, X. Li, et al., Fluoride-salt-cooled high-temperature heactors: review of historical milestones, research status, challenges, and outlook, Renew. Sustain. Energy Rev. 161 (2022) 112345. 
  3. H. Zhao, L. Fick, A. Heald, et al., Development, verification, and validation of an advanced systems code KP-sam for Kairos power fluoride salt-cooled high-temperature reactor (KP-FHR), Nucl. Sci. Eng. (2022) 1-27. 
  4. R.C. Robertson, MSRE Design & Operations Report Part 1 Description of Reactor Design, Oak Ridge National Laboratory, 1965,. ORNL-TM-728. 
  5. H.A. Schmutz, P. Sabharwall, C. Stoots, Tritium Formation and Mitigation in High Temperature Reactors, Idaho National Laboratory, 2012. INL/EXT-12-26758. 
  6. S. Zhang, Study of a passive decay heat removal system and tritium mitigation for fluoride-salt-cooled high-temperature reactors, in: Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 2020. 
  7. M.S. Sohal, M.A. Ebner, P. Sabharwall, et al., Engineering Database of Liquid Salt Thermophysical and Thermochemical Properties, Idaho National Laboratory, 2010,. INL/EXT-10-18297. 
  8. Y. Liu, Y. Song, H. Ai, et al., Corrosion of Cr in molten salts with different fluoroacidity in the presence of CrF3, Corrosion Sci. 169 (2020) 108636. 
  9. L.C. Olson, Materials Corrosion in Molten Lithium Fluoride-Sodium Fluoride-Potassium Fluoride Eutectic Salt, The University of Wisconsin - Madison, United States - Wisconsin, 2009, p. 260. 
  10. P.J. Linstrom, W.G. Mallard, NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg, MD, 2024. 
  11. K. Sridharan, T.R. Allen, in: F. Lantelme, H. Groult (Eds.), Molten Salts Chemistry, Elsevier, Oxford, 2013, pp. 241-267. 
  12. F.-Y. Ouyang, C.-H. Chang, B.-C. You, et al., Effect of moisture on corrosion of Ni-based alloys in molten alkali fluoride FLiNaK salt environments, J. Nucl. Mater. 437 (2013) 201-207. 
  13. M. Kondo, T. Nagasaka, Q. Xu, et al., Corrosion characteristics of reduced activation ferritic steel, JLF-1 (8.92Cr-2W) in molten salts flibe and flinak, Fusion Eng. Des. 84 (2009) 1081-1085. 
  14. W.D. Manly, J.G.M. Adamson, J.H. Coobs, et al., Aircraft Reactor Experiment- Metallurgical Aspects, Oak Ridge National Laboratory, 1958,. ORNL-2349. 
  15. S.S. Raiman, S. Lee, Aggregation and data analysis of corrosion studies in molten chloride and fluoride salts, J. Nucl. Mater. 511 (2018) 523-535. 
  16. D.G. Lovering and R.J. Gale, Molten Salt Techniques Vol. 1. 1983, United States: Plenum Press,New York, NY.. 
  17. G. Zong, Z.-B. Zhang, J.-H. Sun, et al., Preparation of high-purity molten FLiNaK salt by the hydrofluorination process, J. Fluor. Chem. 197 (2017) 134-141. 
  18. J.R. Keiser, J.H. DeVan, E.J. Lawrence, Compatibility of molten salts with type 316 stainless steel and lithium, J. Nucl. Mater. 85-86 (1979) 295-298. 
  19. D.F. Williams, L.M. Toth, K.T. Clarno, Assessment of Candidate Molten Salt Coolants for the Advanced High Temperature Reactor (AHTR), Oak Ridge National Laboratory, 2006,. ORNL/TM-2006/12. 
  20. K.T. Clarno, C.W. Forsberg, J.C. Gehin, et al., Trade Studies for the Liquid-Salt-Cooled Very High-Temperature Reactor: Fiscal Year 2006 Progress Report, Oak Ridge National Laboratory, 2007,. ORNL/TM-2006. 
  21. M.T. Kelley, C.D. Susano, A Method for the Determination of Water in Fluoride Salts, Oak Ridge National Laboratory, 1953. ORNL-1618. 
  22. J.C. Warf, W.D. Cline, R.D. Tevebaugh, Pyrohydrolysis in the determination of fluoride and other halides, Anal. Chem. 26 (1954) 342-346. 
  23. J. Xu, T. Li, T. Yan, et al., Dehydration kinetics and thermodynamics of magnesium chloride hexahydrate for thermal energy storage, Sol. Energy Mater. Sol. Cell. 219 (2021) 110819. 
  24. L.C. Olson, J.W. Ambrosek, K. Sridharan, et al., Materials corrosion in molten LiF-NaF-KF salt, J. Fluor. Chem. 130 (2009) 67-73. 
  25. Sigma-Aldrich, Safety Data Sheet - Hydrogen Fluoride, 2021. 
  26. Sigma-Aldrich, Safety Data Sheet - Hydrogen, 2015. 
  27. S.S. Sawant, B.D. Gajbhiye, S. Tyagi, et al., High temperature corrosion studies in molten salt using salt purification and alloy coating, Indian Chem. Eng. 59 (2017) 242-257. 
  28. S. Zhang, H.-C. Lin, K. Cheng, et al., Design of a high-temperature fluoride salt test facility (HT-FSTF), in: 2019 ANS Winter Meeting, 2019. Washington, D.C. 
  29. P. Gabbott, Principles and Applications of Thermal Analysis, John Wiley & Sons, 2008. 
  30. B. Lothenbach, P. Durdzinski, K. De Weerdt, Thermogravimetric Analysis, A Practical Guide to Microstructural Analysis of Cementitious Materials, vol. 1, 2016, pp. 177-211. 
  31. D.W. Green, R.H. Perry, Perry's Chemical Engineers' Handbook, eighth ed., McGraw-Hill Professional Publishing, Blacklick, United States, 2007. 
  32. R.A. Ross, F. East, C.B. Cooney, et al., Hydration effects in reactions between aluminum and potassium fluorides, Thermochim. Acta 101 (1986) 169-176. 
  33. E. Freeman, V.D. Hogan, Thermoanalysis of some inorganic fluorides and silicofluorides, Anal. Chem. 36 (1964) 2337-2340. 
  34. A.V. Matyskin, Research of Potassium Fluoride Hydration-Dehydration Process, ТОМСК, 2011, pp. 11-13. МАЯ 2011 Г. 
  35. R.A. Nunes, A.P. da Silva Sotero, L.C. Scavarda do Carmo, et al., Photoluminescence of LiF : NaF films at room temperature, J. Lumin. 60-61 (1994) 552-555. 
  36. F. Somma, A. Ercoli, S. Santucci, et al., Production and characterization of multilayer KCl: LiF thin films on glass, J. Vac. Sci. Technol. A: Vacuum, Surfaces, and Films 13 (1995) 1013-1016. 
  37. M.C. Ball, C.M. Snelling, A.N. Strachan, Dehydration of sodium carbonate monohydrate, J. Chem. Soc., Faraday Trans. 1: Physical Chemistry in Condensed Phases 81 (1985) 1761-1766. 
  38. A.C. Baglie, T.C. DeVore, Effect of sample mass on the apparent Arrhenius parameters observed for the thermal dehydration of sodium carbonate monohydrate, Thermochim. Acta 717 (2022) 179364. 
  39. Y. Kirsh, S. Yariv, S. Shoval, Kinetic analysis of thermal dehydration and hydrolysis of MgCl.6HO by DTA and TG, J. Therm. Anal. 32 (1987) 393-408. 
  40. F. Gotzfried, Production of fluoridated salt, Schweiz. Monatsschr. Zahnmed. 116 (2006) 367. 
  41. W.L. Argo, F.C. Mathers, B. Humiston, et al., The electrolytic production of fluorine, J. Phys. Chem. 23 (1919) 348-355.