Solid-State Transformation of Uranyl Peroxide Materials through High-Level Irradiation
Melissa Fairley1, Ginger E Sigmon2, Jay A LaVerne1,3
1Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Inorganic Chemistry
|November 16, 2023
Summary
Radiolysis transforms sodium uranyl triperoxide (NaUT) into sodium uranyl tricarbonate (cejkite). Water presence is crucial for this solid-state conversion, impacting uranyl mobility in natural and industrial settings.
Area of Science:
- Radiochemistry
- Solid-state chemistry
- Materials science
Background:
- Sodium uranyl triperoxide (NaUT) is a precursor material.
- Understanding radiolysis effects is crucial for nuclear waste management and environmental studies.
Purpose of the Study:
- To investigate the solid-state transformation of NaUT induced by radiolysis.
- To determine the influence of irradiation type and environment on the transformation process.
- To identify the final product and its implications for uranyl mobility.
Main Methods:
- Gamma and He-ion irradiation of NaUT.
- Analysis using Raman spectroscopy, infrared spectroscopy (IR), and powder X-ray diffraction (PXRD).
- Investigation under hydrated and dry argon atmospheres.
Main Results:
- Gamma irradiation partially transformed NaUT into a mixed peroxide-carbonate species.
- He-ion irradiation, particularly with hydrated argon, completely converted NaUT to sodium uranyl tricarbonate (cejkite).
- Dry argon was less effective, highlighting water's role in the transformation.
Conclusions:
- Radiolysis can induce a solid-state transformation of NaUT to cejkite.
- The presence of water significantly enhances the conversion efficiency.
- This transformation provides insights into uranyl mobility in natural environments and nuclear waste tanks.
