scholarly journals Pourbaix Diagram for The Prediction of Waste Glass Durability in Geologic Environments

1987 ◽  
Vol 112 ◽  
Author(s):  
Carol M. Jantzen
Keyword(s):  
Nuclear Waste ◽  
Oxidation Potential ◽  
Waste Glass ◽  
Natural Environments ◽  
Long Term Effects ◽  
Pourbaix Diagrams ◽  
Nuclear Waste Glass ◽  
Corrosion Mechanisms ◽  
Different Time Scales

AbstractDissolution of nuclear waste glass occurs by corrosion mechanisms similar to those of metallurgical and mineralogic systems albeit on different time scales. The effects of imposed pH and oxidation potential (Eh) conditions existing in natural environments on metals and minerals have been quantatively and phenomenologically described in compendiums of Pourbaix (pH-potential) diagrams. Construction of Pourbaix diagrams to quantify the response of nuclear waste glasses to repository specific pH and Eh conditions is demonstrated. The expected long-term effects of groundwater contact on the durability of nuclear waste glasses can then be unified.

Materials Interactions Relating to Long-Term Geologic Disposal of Nuclear Waste Glass

1986 ◽  
Vol 84 ◽  
Author(s):  
Ned E. Bibler ◽  
Carol M. Jantzen
Keyword(s):  
Nuclear Waste ◽  
Review Paper ◽  
Waste Glass ◽  
Waste Form ◽  
Glass Waste ◽  
Waste Package ◽  
Geologic Disposal ◽  
Nuclear Waste Glass ◽  
Backfill Materials

AbstractIn the geologic disposal of nuclear waste glass, the glass will eventually interact with groundwater in the repository system. Interactions can also occur between the glass and other waste package materials that are present. These include the steel canister that holds the glass, the metal overpack over the canister, backfill materials that may be used, and the repository host rock. This review paper systematizes the additional interactions that materials in the waste package will impose on the borosilicate glass waste form-groundwater interactions. The repository geologies reviewed are tuff, salt, basalt, and granite. The interactions emphasized are those appropriate to conditions expected after repository closure, e.g. oxic vs. anoxic conditions. Whenever possible, the effect of radiation from the waste form on the interactions is examined. The interactions are evaluated based on their effect on the release and speciation of various elements including radionuclides from the glass. It is noted when further tests of repository interactions are needed before long-term predictions can be made.

Ion-Exchange Interdiffusion Model with Potential Application to Long-Term Nuclear Waste Glass Performance

2016 ◽  
Vol 120 (17) ◽  
pp. 9374-9384 ◽  
Author(s):  
James Joseph Neeway ◽  
Sebastien N. Kerisit ◽  
Jia Liu ◽  
Jiandong Zhang ◽  
Zihua Zhu ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Nuclear Waste ◽  
Potential Application ◽  
Waste Glass ◽  
Nuclear Waste Glass

AEM study of reacted surface layer of borosilicate nuclear waste glasses

1992 ◽  
Vol 50 (1) ◽  
pp. 352-353
Author(s):  
L.M. Wang ◽  
S.A. Kaser ◽  
R.C. Ewing ◽  
J.K. Bates
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Nuclear Waste ◽  
Reaction Pathway ◽  
Sample Surface ◽  
Carbon Films ◽  
Waste Glass ◽  
Thin Sections ◽  
Nuclear Waste Glass

Analysis of the reacted surface layer of borosilicate glass is important to the understanding of the long term nuclear waste glass reaction process. The objective is to assess the simulated nuclear waste glass/water reaction pathway by identifying new crystalline phases that appear on the glass surfaces during the reaction. The results can be used to validate models generated to predict long-term performance of the nuclear waste glass under a range of conditions.In this study, extensive scanning electron microscopy (SEM) with qualitative energy dispersive x-ray spectroscopy (EDS) analysis, quantitative analytical and high resolution transmission electron microscopy (AEM and HRTEM) have been performed on two 202U glasses which were reacted in saturated water vapor for 14 and 23 days, respectively. In order to study the microchemical and microstructural changes with increasing depth from the reaction surface, TEM specimens were prepared in cross-section using the ultramicrotomy slicing technique similar to that described by Bates et al. In this process, small chunks containing the reacted surface layer and a thin layer of glass were first broken off from the sample surface and each of these chunks was then embedded in resin to form a block. Finally, thin sections, approximately 90 nm thick, were microtomed from these blocks and were transfered to copper mesh grids covered by holey carbon films for observation. AEM and HRTEM analyses were accomplished using a JEOL JEM-2000FX microscope attached with a Noran/TN-5500 EDS system at the University of New Mexico.

Comparison of in Situ and Laboratory Corrosion Experiments with Borosilicate Nuclear Waste Glass

1991 ◽  
Vol 257 ◽  
Author(s):  
Werner Lutze ◽  
Rodney C. Ewing
Keyword(s):  
Nuclear Waste ◽  
Laboratory Data ◽  
Waste Glass ◽  
Simulation Test ◽  
In Situ Tests ◽  
Nuclear Waste Glass ◽  
Systems Simulation ◽  
Long Term Behavior

ABSTRACTThe comparison of laboratory data from the corrosion of borosilicate nuclear waste glass (German SM513LW11 and French R7T7) with data from the Materials Interface Interactions Test (MIIT) and Repository Systems Simulation Test (RSST) illustrates the inherent limitations of in situ tests. Although in situ tests may confirm the short term behavior of waste forms and identify phenomena associated with the repository system, they do not provide the fundamental basis for the extrapolation of long-term behavior.

Effects of Heat Treatment on the Microstructure of a Fully Simulated Nuclear Waste Glass

1990 ◽  
Vol 212 ◽  
Author(s):  
Terese V. Palmiter ◽  
I. Joseph ◽  
L. David Pye
Keyword(s):  
Heat Treatment ◽  
Nuclear Waste ◽  
Scanning Transmission Electron Microscopy ◽  
Waste Glass ◽  
Amorphous Phases ◽  
Transmission Electron ◽  
Heat Treated ◽  
Nuclear Waste Glass ◽  
Scanning Transmission

ABSTRACTSamples of a fully simulated nuclear waste glass under consideration for use in the West Valley Demonstration Project were isothermally heat treated and studied by scanning transmission electron microscopy (STEM). Both fully oxidized and partially reduced specimens were heat treated for 3 hours at 600°C, 700°C, 800°C and 900°C and for 45 days at 10°C above Tg (447°C -461°C) and at 10°C below TB (427°C -441°C). Microstructural features in untreated as well as the heat-treated glasses were studied using STEM. Analysis by energy dispersive spectroscopy (EDS) was used to identify the elemental compositions of the features observed.The predominant crystalline phase present in the samples heat treated for 3 hours was an Fe3O4 type spinel with Ni and Cr substituting for some of the Fe. The spinels varied in size from 0.02 to 10.0 µm, the larger crystals present at higher heat-treatment temperatures. Long term heat treatment above Tg resulted in the formation of small iron-containing crystals ranging in size from 10 to 35 nm. Heat treatment below Tg produced no crystalline or amorphous phases.

scholarly journals The Role of Natural Glasses as Analogues in Projecting the Long-Term Alteration of High-Level Nuclear Waste Glasses: Part 1

1993 ◽  
Vol 333 ◽  
Author(s):  
James J. Mazer
Keyword(s):  
Nuclear Waste ◽  
Waste Glass ◽  
Molecular Water ◽  
Natural Environments ◽  
Water Contact ◽  
Natural Analogues ◽  
High Level Nuclear Waste ◽  
Common Observation ◽  
High Level

ABSTRACTThe common observation of glasses persisting in natural environments for long periods of time (up to tens of millions of years) provides compelling evidence that these materials can be kinetically stable in a variety of subsurface environments. This paper reviews how natural and historical synthesized glasses can be employed as natural analogues for understanding and projecting the long-term alteration of high-level nuclear waste glasses. The corrosion of basaltic glass results in many of the same alteration features found in laboratory testing of the corrosion of high-level radioactive waste glasses. Evidence has also been found indicating similarities in the rate controlling processes, such as the effects of silica concentration on corrosion in groundwater and in laboratory leachates. Naturally altered rhyolitic glasses and tektites provide additional evidence that can be used to constrain estimates of long-term waste glass alteration. When reacted under conditions where water is plentiful, the corrosion for these glasses is dominated by network hydrolysis, while the corrosion is dominated by molecular water diffusion and secondary mineral formation under conditions where water contact is intermittent or where water is relatively scarce. Synthesized glasses that have been naturally altered result in alkali-depleted alteration features that are similar to those found for natural glasses and for nuclear waste glasses. The characteristics of these alteration features appear to be dependent on the alteration conditions which affect the dominant reaction processes during weathering. In all cases, care must be taken to ensure that the information being provided by natural analogues is related to nuclear waste glass corrosion in a clear and meaningful way.

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