AI Article Synopsis
Article Abstract
Most of the highly radioactive spent nuclear fuel (SNF) around the world is destined for final disposal in deep-mined geological repositories. At the end of the fuel's useful life in a reactor, about 96% of the SNF is still UO. Thus, the behaviour of UO in SNF must be understood and evaluated under the weathering conditions of geologic disposal, which extend to periods of hundreds of thousands of years. There is ample evidence from nature that many uranium deposits have experienced conditions for which the formation of coffinite, USiO, has been favoured over uraninite, UO, during subsequent alteration events. Thus, coffinite is an important alteration product of the UO in SNF. Here, we present the first evidence of the formation of coffinite on the surface of UO at the time scale of laboratory experiments in a solution saturated with respect to amorphous silica at pH = 9, room temperature and under anoxic conditions.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7376029 | PMC |
| http://dx.doi.org/10.1038/s41598-020-69161-1 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Geochemical Characteristics and Uranium Mineralization Processes in the Shawan Formation of the Chepaizi Uplift, Junggar Basin, Northwestern China.
ACS Omega
December 2024
School of Earth Sciences, East China University of Technology, Nanchang, Jiangxi Province 330013, China.
Article Synopsis
- The Chepaizi Uplift in northwestern China is a key area for exploring uranium resources, particularly in the newly identified Neogene Shawan Formation.
- This study employs advanced techniques like scanning electron microscopy and X-ray diffraction to analyze uranium minerals and understand their geochemical properties.
- The research reveals that uranium mineralization in the Shawan Formation occurred in two stages, influenced by a dry climate and processes involving lateral migration of oxygenated waters followed by hydrocarbons affecting mineral deposits.
Provenance and Tectonic Setting of the Lower Cretaceous Huanhe Formation in the Northwestern Ordos Basin and Its Implications for Uranium Mineralization.
ACS Omega
January 2024
Geological Party No. 208, CNNC, Baotou 014010, Inner Mongolia, China.
The Ordos Basin is an important sandstone-type uranium enrichment region in China, and the Lower Cretaceous Huanhe Formation has attracted significant attention as a newly discovered ore-bearing stratum. To elucidate the provenance, tectonic background, and sedimentary environment constraints on uranium enrichment in the Huanhe Formation sandstone-type uranium deposits, 10 representative sandstone samples from the study area were analyzed by using electron microscopy, X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), and electron probe microanalysis. Independent uranium minerals in the Yihewusu area of Hangjin Banner were shown for the first time to be composed mainly of coffinite and titanium-uranium oxide, with trace amounts of pitchblende.
View Article and Find Full Text PDFInstability of USi in pressurized water media at elevated temperatures.
Commun Chem
May 2021
Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, NM, USA.
Following the Fukushima Daiichi accident, significant efforts from industry and the scientific community have been directed towards the development of alternative nuclear reactor fuels with enhanced accident tolerance. Among the proposed materials for such fuels is a uranium silicide compound (USi), which has been selected for its enhanced thermal conductivity and high density of uranium compared to the reference commercial light water reactor (LWR) nuclear fuel, uranium oxide (UO). To be a viable candidate LWR fuel, however, USi must also demonstrate that, in the event of this fuel coming in contact with aqueous media, it will not degrade rapidly.
View Article and Find Full Text PDFDiagenetic formation of uranium-silica polymers in lake sediments over 3,300 years.
Proc Natl Acad Sci U S A
January 2021
Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, UMR 7590 Sorbonne Université-CNRS-MNHN-IRD (Museum National d'Histoire Naturelle-Institut de Recherche pour le Développement), 75005 Paris, France.
Article Synopsis
- Uranium-contaminated sediments in former mining areas pose significant environmental challenges, particularly regarding their long-term management and understanding of uranium immobilization mechanisms.
- A study of sediments from Lake Nègre reveals changes in uranium speciation over 3,300 years, showing that initial mononuclear U(IV) species transformed into more complex U(IV)-silica structures, which may have led to a partial conversion into a nanocrystalline coffinite-like phase within 700 years.
- The findings highlight the importance of silica availability and suggest that while transformation reduces uranium reactivity, there remains a risk concerning the long-term management of uranium-contaminated sites and waste in similar environments.
A comparative bio-oxidative leaching study of synthetic U-bearing minerals: Implications for mobility and retention.
J Hazard Mater
February 2021
CSIRO Mineral Resources, Clayton, VIC 3168, Australia; School of Applied Sciences RMIT University, Melbourne, VIC 3001, Australia. Electronic address:
In this study, the effects of bio-oxidative leaching on several synthetic uranium minerals - Uraninite [UO], Pitchblende [UO], Coffinite [USiO], Brannerite [UTiO] and Betafite [(U,Ca)(Ti,Nb,Ta)O]) compared to chemical leaching in the presence of pyrite was investigated. In all cases, bio-oxidative leaching was faster and increased overall %U extraction compared to chemical leaching. The results indicated that the bio-oxidative leachability of the uranium minerals was in the order: pitchblende≈ uraninite > coffinite>> brannerite > betafite.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!