Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT) (방사성폐기물학회지)

Korean Radioactive Waste Society (한국방사성폐기물학회)
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Thermodynamic Calculations on the Chemical Behavior of SrO During Electrolytic Oxide Reduction

  • Received : 2020.03.31
  • Accepted : 2020.07.20
  • Published : 2020.09.30
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Abstract

Strontium is known as a salt-soluble element during the electrolytic oxide reduction (EOR) process. The chemical behavior of SrO during EOR was investigated via thermodynamic calculations to provide quantitative data on the chemical status of Sr. To achieve this, thermodynamic calculations were conducted using HSC chemistry software for various EOR conditions. It was revealed that SrO reacts with LiCl salt to produce SrCl2, even in the presence of Li2O, and that the ratio of SrCl2 depends on the initial concentration of Li2O dissolved in LiCl. It was found that SrO reacts with Li to produce Sr during EOR and that the reduced Sr reacts with LiCl salt to produce SrCl2. As a result, the proportions of metallic forms were lower in Sr than in La and Nd under various EOR conditions. The thermodynamic calculations indicated that the three chemical forms of SrO, SrCl2, and Sr co-exist in the EOR system under an equilibrium with Li, Li2O, and LiCl.

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References

  1. E.-Y. Choi, J. Lee, D.H. Heo, S.K. Lee, M.K. Jeon, S.S. Hong, S.-W. Kim, H.W. Kang, S.-C. Jeon, and J.-M. Hur, "Electrolytic reduction runs of 0.6 kg scale-simulated oxide fuel in a $Li_2O$-LiCl molten salt using metal anode shrouds", J. Nucl. Mater., 489, 1-8 (2017). https://doi.org/10.1016/j.jnucmat.2017.03.035
  2. S. Herrmann, S. Li, and M. Simpson, "Electrolytic reduction of spent light water reactor fuel: Bench-scale experiment results", J. Nucl. Sci. Technol., 44(3), 361-367 (2007). https://doi.org/10.1080/18811248.2007.9711295
  3. Y. Sakamura and T. Omori, "Electrolytic reduction and electrorefining of uranium to develop pyrochemical reprocessing of oxide fuels", Nucl. Technol., 171(3), 266-275 (2010). https://doi.org/10.13182/NT10-A10861
  4. S.D. Herrmann, S.X. Li, M.F. Simpson, and S. Phongikaroon, "Electrolytic reduction of spent nuclear oxide fuel as part of an integral process to separate and recover actinides from fission products", Sep. Sci. Technol., 41(10), 1965-1983 (2006). https://doi.org/10.1080/01496390600745602
  5. S. Phongikaroon, S.D. Herrmann, and M.F. Simpson, "Diffusion model for electrolytic reduction of uranium oxides in a molten $LiCl-Li_2O$ salt", Nucl. Technol., 174(1), 85-93 (2011). https://doi.org/10.13182/NT171-85
  6. A. Burak, J. Chamberlain, and M.F. Simpson, "Study of entrainment of $Li_2O$ in product from direct electrolytic reduction of $UO_2$ in molten $LiCl-Li_2O$. Part 1: Post-processing and analysis techniques", J. Nucl. Mater., 529, 151913 (2020). https://doi.org/10.1016/j.jnucmat.2019.151913
  7. W. Park, E.-Y. Choi, S.-W. Kim, S.-C. Jeon, Y.-H. Cho, and J.-M. Hur, "Electrolytic reduction of a simulated oxide spent fuel and the fates of representative elements in a $Li_2O-LiCl$ molten salt", J. Nucl. Mater., 477, 59-66 (2016). https://doi.org/10.1016/j.jnucmat.2016.04.058
  8. S.D. Herrmann and S.X. Li, "Separation and recovery of uranium metal from spent light water reactor fuel via electrolytic reduction and electrorefining", Nucl. Technol., 171(3), 247-265 (2010). https://doi.org/10.13182/NT171-247
  9. B.H. Park, D.-S. Kang, C.-S. Seo, and S.-W. Park, "Development of a mass transfer model and its application to the behavior of the Cs, Sr, Ba, and oxygen ions in an electrolytic reduction process for SF", J. Kor. Rad. Waste Soc., 3(2), 85-93 (2005).
  10. B.H. Park and J.-M. Hur, "Behavior of diffusing elements from an integrated cathode of an electrochemical reduction process", Korean J. Chem. Eng., 27(4), 1278-1283 (2010). https://doi.org/10.1007/s11814-010-0191-x
  11. E.-Y. Choi and H.W. Kang, "Quantitative analysis of barium and strontium in simulated oxide fuel during electrolytic reduction and salt distillation", J. Radioanal. Nucl. Chem., 317(2), 853-862 (2018). https://doi.org/10.1007/s10967-018-5960-8
  12. HSC Chemistry 9.0 software, Outotec, Pori, Finland.
  13. M.K. Jeon, S.-W. Kim, and E.-Y. Choi, "Thermodynamic investigation on the behavior of rare earth oxides during electrolytic reduction process", J. Radioanal. Nucl. Chem., 317(2), 1089-1093 (2018). https://doi.org/10.1007/s10967-018-5975-1
  14. J.-M. Hur, S.M. Jeong, and H. Lee, "Underpotential deposition of Li in a molten $LiCl-Li_2O$ electrolyte for the electrochemical reduction of U from uranium oxides", Electrochem. Commun., 12(5), 706-709 (2010). https://doi.org/10.1016/j.elecom.2010.03.012
  15. J. Liu and J.-C. Poignet, "Measurement of the activity of lithium in dilute solutions in molten lithium chloride between $650^{\circ}C$ and $800^{\circ}C$", J. Appl. Electrochem., 20(5), 864-867 (1990). https://doi.org/10.1007/BF01094318

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