Formulation, Testing, and Structural Characterization of High-Zirconium High-Level Waste Glasses

1999 ◽  
Vol 556 ◽  
Author(s):  
David A. McKeown ◽  
Isabelle S. Muller ◽  
Andrew C. Buechele ◽  
Ian L. Pegg ◽  
Christopher A. Kendziora ◽  
...  
Keyword(s):  
High Level Waste ◽  
Borosilicate Glasses ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Potential Applications ◽  
High Level Nuclear Waste ◽  
High Level ◽  
A Minor ◽  
Zirconia Content

AbstractA range of compositions of high-zirconia borosilicate glasses were formulated and their structures investigated by a combination of techniques. These compositions have potential applications for high-level nuclear waste storage in combination with advanced reprocessing methods. Raman and Zr EXAFS data were collected for a series of glasses spanning a range of zirconia concentrations. The Raman spectra indicate that Zr acts as a silicate network modifier, where the silicate tetrahedral network depolymerizes as the zirconia content increases. Zr EXAFS analysis indicates that Zr is found in octahedral sites, and to a minor extent, sevencoordinated sites. As the zirconia content increases, the fraction of seven-coordinated Zr-sites increases; this may be the cause of ZrO2 baddeleyite crystallization that was observed in some Zr-rich glasses investigated.

Study of Melted Synroc Doped with Simulated High-Level Waste

1996 ◽  
Vol 465 ◽  
Author(s):  
I. A. Sobolev ◽  
S. V. Stefanovsky ◽  
S. V. Ioudintsev ◽  
B. S. Nikonov ◽  
B. I. Omelianenko ◽  
...  
Keyword(s):  
Bulk Composition ◽  
Barometric Pressure ◽  
High Level Waste ◽  
Savannah River ◽  
Savannah River Plant ◽  
High Level ◽  
A Minor ◽  
Simulated High Level Waste ◽  
Additional Phase

ABSTRACTPreparation and characterization of inductively-melted Synroc containing 20 wt% simulated plant “Mayak” reprocessing waste were performed. The sample bulk composition was as follows, (in wt.%): 55.4 TiO2; 15.8 ZrO2; 7.5 CaO; 7.4 BaO; 4.3 Al2O3 2.0 MnO; 1.8 SiO2; 0.7 Na2O; 1.9 K2O, 0.5 Ce2O3; 1.0 UO2; 0.9 NiO; 0.6 Cr2O3, and 0.2 FeO. The sample was produced by melting in air at 1550–1600 °C under barometric pressure. It is composed of a few crystalline phases and a minor glass phase. Most of the phases (hollandite, zirconolite, perovskite and rutile) are similar to the analogous phases found in the other Synroc formulations. An additional phase with average composition, wt.%: 59.8 TiO2; 15.6 CaO; 7.0 UO2; 5.6 ZrO2; 4.7 MnO; 4.1 Ce2O3, and 1.8 Al2O3 was found. Some elements (Ba, Si, Ni, K, Na, Fe) were present in the phase in negligible quantities. Its formula (Ca2.65U0.3Ce0.2)(Ti7.3Mn0.6Zr0.4Al0.3)O20.0 is rather close to a rare mineral uhligite - Ca3(Ti,Zr,Al)9O20. Another possible counterpart of the phase is murataite-like mineral previously described in tailored ceramic designed for Savannah River Plant wastes fixation. This phase as well as zirconolite are the major host for U in the sample Preliminary data on the material leachability in water at 350 °C and 50 MPa have been obtained Uranium contents in the solution were about 1 ppb and close to the uranium dioxide solubility in deionized water under the same P-T conditions.

scholarly journals Post Emplacement Environment of Waste Packages

1983 ◽  
Vol 26 ◽  
Author(s):  
K. G. Knauss ◽  
V. M. Oversby ◽  
T. J. Wolery
Keyword(s):  
Water Chemistry ◽  
Geographic Location ◽  
High Level Waste ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Reaction Extent ◽  
Waste Repository ◽  
High Level ◽  
Water Ratio ◽  
Topopah Spring Tuff

ABSTRACTExperiments have been conducted as part of the Nevada Nuclear Waste Storage Investigations Project to determine the changes in water chemistry due to reaction of the Topopah Spring tuff with natural groundwater at temperatures up to 150°C. The reaction extent has been investigated as a function of rock-to-water ratio, temperature, reaction time, physical state of the samples, and geographic location of the samples within the tuff unit. Results of these experiments will be used to provide information on the water chemistry to be expected if a high level waste repository were to be constructed in the Topopah Spring tuff.

Characterization of High-Level Nuclear Waste Glass Using Magnetic Measurements

1993 ◽  
Vol 333 ◽  
Author(s):  
Frank E. Senftle ◽  
Arthur N. Thorpe ◽  
Julius R. Grant ◽  
Aaron Barkatt
Keyword(s):  
Nuclear Waste ◽  
Magnetic Measurements ◽  
Rapid Quenching ◽  
Small Sample ◽  
High Level Waste ◽  
Air Cooling ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Simulated High Level Waste

ABSTRACTMagnetic measurements constitute a promising method for the characterization of nuclear waste glasses in view of their simplicity and small sample weight requirements.Initial studies of simulated high-level waste glasses show that the Curie constant is generally a useful indicator of the Fe2+:Fe3+ ratio. Glasses produced by air-cooling in large vessels show systematic deviations between experimental and calculated values, which are indicative of the presence of small amounts of crystalline iron-containing phases. Most of the iron in these phases becomes dissolved in the glass upon re-heating and more rapid quenching. The studies further show that upon leaching the glass in water some of the iron in the surface regions of the glass is converted to a form which has high temperature-independent magnetic susceptibility.

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