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Title: Investigation of Uranium Polymorphs

Abstract

The UO3-water system is complex and has not been fully characterized, even though these species are common throughout the nuclear fuel cycle. As an example, most production schemes for UO3 result in a mixture of up to six or more different polymorphic phases, and small differences in these conditions will affect phase genesis that ultimately result in measureable changes to the end product. As a result, this feature of the UO3-water system may be useful as a means for determining process history. This research effort attempts to better characterize the UO3-water system with a variety of optical techniques for the purpose of developing some predictive capability for estimating process history in polymorphic phases of unknown origin. Three commercially relevant preparation methods for the production of UO3 were explored. Previously unreported low temperature routes to β- and γ-UO3 were discovered. Raman and fluorescence spectroscopic libraries were established for pure and mixed polymorphic forms of UO3 in addition to the common hydrolysis products of UO3. An advantage of the sensitivity of optical fluorescence microscopy over XRD has been demonstrated. Preliminary aging studies of the α and γ forms of UO3 have been conducted. In addition, development of a 3-D phase field modelmore » used to predict phase genesis of the system was initiated. Thermodynamic and structural constants that will feed the model have been gathered from the literature for most of the UO3 polymorphic phases.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1062522
Report Number(s):
PNNL-20951
400904120
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
uranium polymorphs; UO3; uranium trioxide; uranium oxide hydrolysis; uranium optical spectroscopy; uranium oxides

Citation Formats

Sweet, Lucas E, Henager, Charles H, Hu, Shenyang Y, Johnson, Timothy J, Meier, David E, Peper, Shane M, and Schwantes, Jon M. Investigation of Uranium Polymorphs. United States: N. p., 2011. Web. doi:10.2172/1062522.
Sweet, Lucas E, Henager, Charles H, Hu, Shenyang Y, Johnson, Timothy J, Meier, David E, Peper, Shane M, & Schwantes, Jon M. Investigation of Uranium Polymorphs. United States. https://doi.org/10.2172/1062522
Sweet, Lucas E, Henager, Charles H, Hu, Shenyang Y, Johnson, Timothy J, Meier, David E, Peper, Shane M, and Schwantes, Jon M. 2011. "Investigation of Uranium Polymorphs". United States. https://doi.org/10.2172/1062522. https://www.osti.gov/servlets/purl/1062522.
@article{osti_1062522,
title = {Investigation of Uranium Polymorphs},
author = {Sweet, Lucas E and Henager, Charles H and Hu, Shenyang Y and Johnson, Timothy J and Meier, David E and Peper, Shane M and Schwantes, Jon M},
abstractNote = {The UO3-water system is complex and has not been fully characterized, even though these species are common throughout the nuclear fuel cycle. As an example, most production schemes for UO3 result in a mixture of up to six or more different polymorphic phases, and small differences in these conditions will affect phase genesis that ultimately result in measureable changes to the end product. As a result, this feature of the UO3-water system may be useful as a means for determining process history. This research effort attempts to better characterize the UO3-water system with a variety of optical techniques for the purpose of developing some predictive capability for estimating process history in polymorphic phases of unknown origin. Three commercially relevant preparation methods for the production of UO3 were explored. Previously unreported low temperature routes to β- and γ-UO3 were discovered. Raman and fluorescence spectroscopic libraries were established for pure and mixed polymorphic forms of UO3 in addition to the common hydrolysis products of UO3. An advantage of the sensitivity of optical fluorescence microscopy over XRD has been demonstrated. Preliminary aging studies of the α and γ forms of UO3 have been conducted. In addition, development of a 3-D phase field model used to predict phase genesis of the system was initiated. Thermodynamic and structural constants that will feed the model have been gathered from the literature for most of the UO3 polymorphic phases.},
doi = {10.2172/1062522},
url = {https://www.osti.gov/biblio/1062522}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2011},
month = {Mon Aug 01 00:00:00 EDT 2011}
}