Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

2020 ◽  
Vol 11 (4) ◽  
pp. 660-675 ◽  
Author(s):  
Hua Chen ◽  
José Marcial ◽  
Mostafa Ahmadzadeh ◽  
Deepak Patil ◽  
John McCloy
Keyword(s):  
Nuclear Waste ◽  
Rare Earths ◽  
Glass Ceramics ◽  
Waste Glass ◽  
Nuclear Waste Glass

Secondary Phase Formation and the Microstructural Evolution of Surface Layers During Vapor Phase Alteration of the French Son68 Nuclear Waste Glass at 200 °C

1995 ◽  
Vol 412 ◽  
Author(s):  
W. L. Gong ◽  
R. C. Ewing ◽  
L. M. Wang ◽  
E. Vernaz ◽  
J. K. Bates ◽  
...  
Keyword(s):  
Surface Layer ◽  
Nuclear Waste ◽  
Vapor Phase ◽  
Rare Earths ◽  
Waste Glass ◽  
Transition Elements ◽  
Surface Layers ◽  
Crystalline Phases ◽  
Developed Surface ◽  
Nuclear Waste Glass

AbstractThe SON68 inactive “R7T7” composition is the French reference glass for the LWR nuclear waste glass. Vapor phase alteration was used to accelerate the reaction progress of glass corrosion and to develop the characteristic suite of secondary, alteration phases. Extensive solid-state characterization (AEM/SEM/HRTEM) was completed on six inactive R7T7 waste glasses which were altered in the presence of saturated water vapor (200 °C) for 91, 241, 908, 1000, 1013, and 1021 days. The AEM samples were examined in cross-section (lattice-fringe imaging, microdiffraction, and quantitative thin-film EDS analysis). The glass monoliths were invariably covered with a thin altered rind. The layer became thicker with time: 0.5μm for 22 days; 4 μm for 91 days; 6 μm for 241 days; 10 μm for 908 days; 26 μm for 1013 days; and <35μm for 1021 days. The composite alteration layer of the SON68 samples is at least four time less thick than that of the SRL 131 glass composition.Six distinctive zones, based on phase chemistry and microstructure, were distinguished within the well-developed surface layers. Numerous crystalline phases such as analcime, tobermorite, apatite, and weeksite were identified on the surfaces of the reacted glasses as precipitates. Two crystalline phases, Ag2TeO3 and (Ca,Sr)Mo3O9(OH)2, were found within the inner zones of surface layers, and they must have nucleated in situ, indicating that Ag, Te, Sr, and Mo can be retained within the surface layer. The majority of the surface layer volume is composed of two morphologically and chemically different structures: one consists of well-crystallized fibrous smectite aggregates occurring along with cavities, the A-domain; and the other consists of poorlycrystallized regions containing needle-like smectite (montmorillonite) crystallites, a silica-rich amorphous matrix, and possibly ZrO2 particles, the B-domain. The retention of rare-earths and Zr mostly occurred within B-domains and that of transition elements, such as Zn, Cr, Ni, and Mn, in A-domains. The recrystallization of poorly-crystallized B-domains into well-crystallized Adomains may influence the long-term behavior of rare-earths, Zr, and transition elements. The mechanism of surface layer formation during vapor phase alteration is discussed based on the cross-sectional AEM studies of surface layers of the SON68 waste glasses.

scholarly journals Crystallization study of rare earth and molybdenum containing nuclear waste glass ceramics

2019 ◽  
Vol 102 (9) ◽  
pp. 5149-5163 ◽  
Author(s):  
John S. McCloy ◽  
Brian J. Riley ◽  
Jarrod Crum ◽  
José Marcial ◽  
Joelle T. Reiser ◽  
...  
Keyword(s):  
Rare Earth ◽  
Nuclear Waste ◽  
Glass Ceramics ◽  
Waste Glass ◽  
Nuclear Waste Glass ◽  
Crystallization Study

Infrared Spectroscopy Structural Analysis of Corroded Nuclear Waste Glass K-26

2008 ◽  
Author(s):  
Sergey Stefanovsky ◽  
Alexander Barinov ◽  
Galina Varlakova ◽  
Irene Startseva ◽  
Michael I. Ojovan
Keyword(s):  
Infrared Spectroscopy ◽  
Structural Analysis ◽  
Nuclear Waste ◽  
Waste Glass ◽  
Nuclear Waste Glass

scholarly journals History of Nuclear Waste Glass in France

2014 ◽  
Vol 7 ◽  
pp. 3-9 ◽  
Author(s):  
Étienne Vernaz ◽  
Jérôme Bruezière
Keyword(s):  
Nuclear Waste ◽  
Waste Glass ◽  
Nuclear Waste Glass ◽  
History Of

Hydrotalcite Formed by Alteration of R7T7 Nuclear Waste Glass and Basaltic Glass in Salt Brine at 190°C

1993 ◽  
Vol 333 ◽  
Author(s):  
A. Abdelouas ◽  
J. L. Crovisier ◽  
W. Lutze ◽  
R. Müller ◽  
W. Bernotat
Keyword(s):  
Nuclear Waste ◽  
Waste Glass ◽  
Aluminium Content ◽  
Basaltic Glass ◽  
Alteration Product ◽  
Nuclear Waste Glass ◽  
Salt Brine ◽  
High Aluminium ◽  
Early Alteration

ABSTRACTThe R7T7 and synthetic basaltic glasses were submitted to corrosion in a saline MgCl2dominated solution at 190°C. For both glasses, the early alteration product is a hydrotalcite-like compound in which HPO42-, SO4-2and Cl-substitutes to CO32. The measured d003spacing is 7.68 Å for the hydrotalcite formed from R7T7 glass and 7.62 Å for the hydrotalcite formed from basaltic glass which reflect the high aluminium content. Chemical microanalyses show that the hydrotalcite is subsequently covered by a silica-rich gel which evolves into saponite after few months.

scholarly journals Does Fully Radioactive Glass Behave Differently than Simulated Waste Glass?

1992 ◽  
Vol 294 ◽  
Author(s):  
X. Feng ◽  
J. K. Bates ◽  
C. R. Bradley ◽  
E. C. Buck
Keyword(s):  
Radiation Field ◽  
Nuclear Waste ◽  
Potassium Feldspar ◽  
Waste Glass ◽  
Solution Ph ◽  
Static Tests ◽  
Leach Rate ◽  
Nuclear Waste Glass ◽  
Surface Alteration ◽  
Leach Behavior

ABSTRACTStatic tests at SA/V (ratio of surface area of glass to solution volume) 20,000 m−1 on SRL 200 glass compositions show that, at long test periods, the simulated nuclear waste glass (nonradioactive) leaches faster than the corresponding radioactive glass by a factor of about 40, although comparative tests, done through 560 days, at lower SA/V, 2000 m−1, indicate little difference in the leach behavior of the two types of glasses. The similarity in leach behavior between radioactive and simulated glasses at SAN of 2000 m−1 or lower is also observed for SRL 165/42 and 131/11 compositions. The accelerated glass reaction with the simulated glass 200S is associated with the formation of crystalline phases such as clinoptilolite (or potassium feldspar), and a pH excursion. The radiation field generated by the fully radioactive glass reduces the solution pH. This lower pH, in turn, may retard the onset of increased reaction rate. The radiation field generated by the radioactive glasses does not directly affect the stability of the glass surface alteration layer under those conditions where the radioactive and simulated glasses react at the same rate. These results suggest that the fully radioactive nuclear waste glass 200R may maintain a much lower leach rate than the simulated 200S, if the lower pH in the 200R leachate can be sustained. Meaningful comparison tests between radioactive and simulated nuclear waste glasses should include long-term and high SA/V tests.

scholarly journals Hydrogen Speciation in Hydrated Layers on Nuclear Waste Glass

1986 ◽  
Vol 84 ◽  
Author(s):  
Roger D. Aines ◽  
Homer C. Weed ◽  
John K. Bates
Keyword(s):  
Nuclear Waste ◽  
Vapor Phase ◽  
Waste Glass ◽  
Hydroxyl Group ◽  
Molecular Water ◽  
Hydroxyl Groups ◽  
Phase Layer ◽  
Nuclear Waste Storage ◽  
Nuclear Waste Glass ◽  
Saturated Atmosphere

AbstractThe hydration of an outer layer on nuclear waste glasses is known to occur during leaching, but the actual speciation of hydrogen (as water or hydroxyl groups) in these layers has not been determined. As part of the Nevada Nuclear Waste Storage Investigations Project, we have used infrared spectroscopy to determine hydrogen speciations in three nuclear waste glass compositions (SRL-131 & 165, and PNL 76-68), which were leached at 90°C (all glasses) or hydrated in a vapor-saturated atmosphere at 202°C (SRL-131 only). Hydroxyl groups were found in the surface layers of all the glasses. In addition, molecular water was found in the surface of SRL-131 and PNL 76-68 glasses that had been leached for several months in deionized water, and in the vapor-hydrated sample. The water/hydroxyl ratio increases with increasing reaction time; molecular water makes up most of the hydrogen in the thick reaction layers on vapor-phase hydrated glass while only hydroxyl occurs in the least reacted samples. Using the known molar absorptivities of water and hydroxyl in silica-rich glass the vapor-phase layer contained 4.8 moles/liter of molecular water, and 0.6 moles water in the form hydroxyl. A 15 micrometer layer on SRL-131 glass formed by leaching at 90°C contained a total of 4.9 moles/liter of water, 2/3 of which was as hydroxyl. The unreacted bulk glass contains about 0.018 moles/liter water, all as hydroxyl.The amount of hydrogen added to the SRL-131 glass was about 70% of the original Na + Li content, not the 300% that would result from alkali-hydronium ion (H30+) interdiffusion. If all the hydrogen is then assumed to be added as the result of alkali-H+ interdiffusion, the molecular water observed may have formed from condensation of the original hydroxyl groups according to:20H = H20 molecular + 00where 00 refers to a bridging oxygen, and OH refers to a hydroxyl group attached to a silicate polymer. The hydrated layer on the nuclear waste glasses appears to be of relatively low water content (4 to 7% by weight) and is not substantially hydroxylated. Thus, these layers do not have many of the properties associated with “gel” layers.

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