1. Formation of β-U3O8from UCl3Salt Compositions under Oxygen Exposure
- Author
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Tuffy, Benjamin W., Birkner, Nancy R., Schorne-Pinto, Juliano, Davis, Ryan C., Mofrad, Amir M., Dixon, Clara M., Aziziha, Mina, Christian, Matthew S., Lynch, Timothy J., Bartlett, Maxwell T., Besmann, Theodore M., Brinkman, Kyle S., and Chiu, Wilson K. S.
- Abstract
Complementary X-ray absorption fine structure (XAFS) and Raman spectroscopy studies were conducted on various UCl3concentrations in alkali chloride salt compositions. The samples were 5 mol % UCl3in LiCl (S1), 5 mol % UCl3in KCl (S2), 5 mol % UCl3in LiCl–KCl eutectic (S4), 50 mol % UCl3in KCl (S5), and 20 mol % UCl3in KCl (S6) molar concentrations. Samples were heated to 800 °C and allowed to cool to room temperature with measurements performed at selected temperatures; the highest temperatures showed the most stability and will be primarily referenced for conclusions. The processing and interpretation of the Raman and extended X-ray absorption fine structure (EXAFS) peaks revealed several uranium–oxygen bond lengths and symmetries in the samples before, during, and after heating. Based on published thermodynamic data of similar systems, X-ray absorption fine structure spectroscopy, and identification of Raman peaks, a β variation of α-U3O8, typical at room temperature, is the suspected dominant phase of all samples at high temperatures (800 °C). In the existing literature, this β structure of U3O8was synthesized by slow cooling of uranium oxides from 1350 °C. This paper suggests the rapid formation of the compound due to the decomposition of the uranium chlorides or oxychlorides at increasing temperatures and O2reaction kinetics.
- Published
- 2024
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