Characterization of the Surface of the HLW Glass R7T7 Reacted in Salt Brines

1988 ◽  
Vol 127 ◽  
Author(s):  
H. Roggendorf ◽  
R. Conradt ◽  
H. Schmidt
Keyword(s):  
Surface Composition ◽  
Volume Ratio ◽  
Product Layer ◽  
Waste Form ◽  
Borosilicate Glasses ◽  
Federal Republic Of Germany ◽  
Reaction Product Layer ◽  
Solution Volume

ABSTRACTBorosilicate glasses are proposed as waste form for the final disposal of High Level Waste (HLW) in salt formations by the Federal Republic of Germany. To check the safety of this waste form the corrosion of the non-radioactive borosilicate glass R7T7 in salt brines has been studied in collaboration with the Hahn-Meitner-Institut, Berlin. Temperatures up to 190°C and S/V ratios (surface area to solution volume ratio) between 3.3 and 1000 m were applied. S/V was varied by the addition of glass powder. The results presented here concern the characterization of the surface composition of the corroded glass (corroded at 190°C in a brine containing high amounts of MgCl-, called Q brine in this paper) after removing the reaction product layer. The corrosion conditions were chosen to obtain samples typical of long term (silica saturation) corrosion. The surface composition was analyzed quantitatively by X-ray photoelectron spectroscopy (XPS) by using external standard glasses with a composition similar to R7T7. Additionally scanning electron microscopy (SEM) was employed.

scholarly journals Aem Analyses of SRL 131 Glass Altered as a Function of SA/V

1991 ◽  
Vol 257 ◽  
Author(s):  
James J. Mazer ◽  
John K. Bates ◽  
Bruce M. Biwer ◽  
C. R. Bradley
Keyword(s):  
Experimental Studies ◽  
Volume Ratio ◽  
Scaling Factor ◽  
Experimental Results ◽  
Geologic Repository ◽  
Short Term ◽  
Natural Systems ◽  
Test Conditions ◽  
Solution Volume

Experimental studies of silicate glass/water reactions at low temperatures have previously identified the glass surface area-to-solution volume ratio (SA/V) as a significant rate determining parameter [1-4]. The value produced when SA/V is multiplied by reaction time, hereafter referred to as SVT, has been proposed as a scaling factor for comparing experimental results collected under different test conditions and for extrapolating short-term results to longer periods of time. Developing an understanding of the effect of SAN is needed for modeling experimental results where SA/V ranges in value or may vary during experiments. It is also useful to understand the effect of SA/V for modeling natural systems where this value almost certainly varies, such as during the hydrothermal diagenesis of natural glasses or projecting the long-term reaction of water and borosilicate nuclear waste glass in a geologic repository.

Raman studies of technetium in borosilicate waste glass

2007 ◽  
Vol 95 (5) ◽  
Author(s):  
David A. McKeown ◽  
Andrew C. Buechele ◽  
Wayne W. Lukens ◽  
D. K. Shuh ◽  
Ian L. Pegg
Keyword(s):  
Raman Spectroscopy ◽  
Waste Glass ◽  
Borosilicate Glasses ◽  
Coordination Environment ◽  
X Ray ◽  
Waste Vitrification ◽  
X Ray Absorption ◽  
Raman Spectral

The characterization of technetium (Tc) environments in borosilicate glasses is important with regard to the long-term isolation of Tc in nuclear wastes from the environment by waste vitrification. In this study, Raman spectroscopy was used to detect Tc in various borosilicate waste glass formulations in which Tc valence and average coordination environment were previously characterized by X-ray absorption spectroscopy. Raman spectral comparisons between chemically equivalent Tc-containing and Tc-free borosilicate glass pairs indicate Tc-dependent features near 320 and 910 cm

Leached Nuclear Waste Glasses: Ultramicrotomy and AEM Characterization

1990 ◽  
Vol 48 (2) ◽  
pp. 444-445
Author(s):  
J.P. Bradley ◽  
J.K. Bates
Keyword(s):  
Nuclear Waste ◽  
Waste Form ◽  
Experimental Program ◽  
Nuclear Waste Repository ◽  
Aqueous Environment ◽  
Borosilicate Glasses ◽  
Secondary Phases ◽  
Thin Sections ◽  
The Stability

The long term performance of a nuclear waste repository depends ultimately on the stability of the waste form. Borosilicate glasses have been proposed as a waste form because they can incorporate radionuclides into their structures and they are relatively resistant to corrosion in an aqueous environment. Experimental and computer modeling programs are in progress to evaluate their long term stability in a geological repository. In the experimental program, glasses have been reacted in sealed vessels (for between 7 and 280 days) to simulate the effects of terrestrial aqueous alteration (leaching). During leaching, a layer of secondary phases (predominantly layer silicates) builds up on the glass surfaces (Pigs. 1-3). Determination of the mineralogy of the leached layer is critical for evaluation of glass performance, but the layers are typically ultra-thin (1-50 μm), poorly crystallized, friable coatings that have eluded detailed characterization. Using ultramicrotomy, we have successfully prepared electron transparent thin-sections of the glasses plus leached layers with minimal disturbance of their indigenous microstructures (Figs. 2-4).

scholarly journals Basalt Glass: An Analogue for the Evaluation of the Long-Term Stability of Nuclear Waste form Borosilicate Glasses

1984 ◽  
Vol 44 ◽  
Author(s):  
C. D. Byers ◽  
M. J. Jercinovic ◽  
R. C. Ewing ◽  
K. Keil
Keyword(s):  
Nuclear Waste ◽  
Laboratory Data ◽  
Waste Form ◽  
Borosilicate Glasses ◽  
Term Stability ◽  
Long Term Stability ◽  
Basalt Glass ◽  
Time Periods ◽  
Basalt Glasses

AbstractThe long-term stability of nuclear waste form borosilicate glasses can be evaluated by understanding the processes that effect the long-term alteration of glass and by comparing laboratory alteration of synthetic basalt and borosilicate glasses with the observed stability of naturally occurring basaltic glasses in diverse geologic environments. This paper presents detailed electron microprobe analyses of naturally altered basaltic glasses (with maximum ages of 10,000 to 20 million years) from low-temperature environments. These results are compared to laboratory data on the corrosion of a synthetic basaltic glass in MCC-1 tests (90°C, a SA/V of 0.1 cm−1 and time periods up to 182 days), MCC-2 tests (190°C, a SA/V of 0.1 cm−1 and time periods up to 210 days) and hydration tests in saturated water vapor (240°C, an estimated SA/V of ∼ 106 cm−1 and time periods up to 63 days). Additionally, laboratory induced hydration alteration of synthetic basalt and borosilicate glasses is compared. These preliminary experiments provide evidence that the alteration processes observed for natural basalt glasses are relevant to understanding the alteration of nuclear waste glass, as both appear to react via similar processes.

Characterization of Steel/Concrete Interface for a Long-Term Corroded Beam Stored in Chloride Environment

2010 ◽  
Vol 163-167 ◽  
pp. 3415-3420 ◽  
Author(s):  
Rui Jin Zhang ◽  
Hui Lin Yang ◽  
Valérie L’Hostis ◽  
Arnaud Castel ◽  
Raoul François
Keyword(s):  
Spatial Distribution ◽  
Iron Oxides ◽  
Product Layer ◽  
Chemical Compositions ◽  
Iron Species ◽  
Corrosion Product Layer ◽  
Chloride Environment ◽  
Concrete Interface

This paper deals with the steel/concrete interface of a corroded beam B2CL1 after a 23 years exposure in chloride environment. XRD, SEM and Raman techniques were performed to investigate the chemical compositions and the spatial distribution of corrosion products. The experimental results illustrate that the corrosion product layer is a multi-layer constituted as marbling structure. It is composed of a mix of iron oxides and iron oxi-hydroxides. Iron species were found in the vicinity of concrete mainly in cracks, as it was already observed in the literature.

Development and Characterization of Borosilicate Glasses for Immobilization of Plutonium-containing Alkaline Sludges

2000 ◽  
Vol 663 ◽  
Author(s):  
A.S. Aloy ◽  
O.A. Iskhakova ◽  
T.I. Koltsova ◽  
A.V. Trofimenko ◽  
L.J. Jardine
Keyword(s):  
Sodium Content ◽  
Scale Production ◽  
Borosilicate Glasses ◽  
Electron Probe Analysis ◽  
High Sodium ◽  
Long Term Storage ◽  
Before And After ◽  
Ray Methods

ABSTRACTSeveral glasses were melted using laboratory-scale microwave (MW) equipment to study the vitrification of Pu-containing sludges from the Mining and Chemical Combine in Zheleznogorsk, Russia. This work is part of an effort to identify glass compositions that can be adopted for industrial scale production. The glass must meet durability requirements and have good technological properties for long-term storage and geologic disposal.Electron Probe Analysis (EMPA), scanning electron microscope (SEM) and x-ray methods were used to characterize glasses containing 50 wt% solid sludge residues with high sodium content.Leach tests of 3, 7, 14, and 28 day durations were performed using the MCC-1 method at 90°C. The surface of the glass was analyzed before and after leaching. Based on the observed results, there are differences in the behavior of Pu and U for the glasses tested, and glass durability is dependent on homogeneity, the uranium oxidizing state, and the SiO2/Na2O+Li2O ratio.

Chemical Stability of Simiulated HLW Forms in Contact With Clay Media

1981 ◽  
Vol 11 ◽  
Author(s):  
P. Van Iseghem ◽  
W. Timmerans ◽  
R. De Batist
Keyword(s):  
Corrosion Behaviour ◽  
Volume Ratio ◽  
Water Mixture ◽  
Borosilicate Glasses ◽  
Corrosion Stability ◽  
Corrosion Rates ◽  
Waste Forms ◽  
Reference Medium ◽  
Saturation Effects ◽  
Solution Volume

ABSTRACTThe corrosion stability of six simulated HLW forms proposed by several European countries (five borosilicate glasses and one borosilicate glass ceramic) in contact with different media relating to the clay disposal has been investigated for periods up to 80 days and at a surface area to solution volume ratio of 1 cm−1 under non de-aerated conditions. In the reference medium distilled water the corrosion stabilities are largely determined by saturation effects for elements such as Si, Ca, Mg, Sr, Fe and U. Si saturation is found to be enhanced by a large Al2O3 concentration in the glass. In the clay-water mixture these saturation effects are much less predominant. Wet clay attacks the waste forms faster than the clay-water mixture, although the corrosion rates tend to decrease with time in both clay media. In general, no simple Arrhenius-type temnnerature dependence for the corrosion behaviour is found for the interval between 40 and 200°C.

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