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DOE OSTI · 2377310

Solid-state transformation of uranyl peroxide materials through high-level irradiation

Fairley, Melissa Rier Catherine·Sigmon, Ginger E.·LaVerne, Jay A.
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Abstract

The solid-state transformation of sodium uranyl triperoxide (Na 4 (UO 2 )(O 2 ) 3 ∙9H 2 O, NaUT) to sodium uranyl tricarbonate (Na 4 (UO 2 )(CO 3 ) 3 ) by radiolysis has been observed for the first time. The exposure of NaUT to 3 MGy gamma irradiation resulted in partial breakdown of the peroxides forming a mixed peroxide and carbonate species. The effects of He ion irradiation on NaUT was also investigated up to 225 MGy using both hydrated argon and dry argon. The complete conversion to the uranyl tricarbonate phase by 56 MGy using hydrated argon, while dry argon did not fully convert showing the importance of water in the system. He-ion irradiated NaUT samples all convert to the tricarbonate phase with time in air post radiation exposure. This transition was monitored via Raman spectroscopy, infrared spectroscopy (IR), and powder X-ray diffraction (PXRD) to further confirm the identity of the final product as the sodium uranyl tricarbonate, čejkaite. This transformation outlines a mechanism for the mobility of uranyl in natural environments and in the Hanford tanks.

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38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRYCarbonatesIrradiationPeroxidesUranyl

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Fairley, Melissa Rier Catherine, Sigmon, Ginger E., LaVerne, Jay A.. 2023-11-16. Solid-state transformation of uranyl peroxide materials through high-level irradiation. https://doi.org/10.2172/2377310

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