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 Near-Surface Leaching Studies of Pb-Implanted Savannah River Waste Glass

1981 ◽  
Vol 11 ◽  
Author(s):  
G. W. Arnold ◽  
C. J. M. Northrup ◽  
N. E. Bibler
Keyword(s):  
Energy Deposition ◽  
Surface Damage ◽  
High Level Waste ◽  
Savannah River ◽  
Near Surface ◽  
Ion Tracks ◽  
Savannah River Plant ◽  
High Level ◽  
Storage Times ◽  
Long Storage

Ion implantation into simulated nuclear waste glasses is a rapid means of producing near-surface energy deposition similar to that produced by α-recoil nuclei after long storage times (typically 103 – 106 years). For example, Dran, Maurette, and Petit1 used 200 keV Pb-ion implantations in glass at a fluence of 5 × 1012/cm2 to produce surface damage. This fluence is equivalent to approximately 2 × 1018 alpha-decays/cm3 which corresponds to approximately 106 years storage for glass containing Savannah River Plant (SRP) defense high-level waste (DHLW). These authors1 found that this fluence value corresponded to a critical fluence (Φc) for enhanced etching (a factor of 20 increase as inferred by step-height changes) for several silicate glasses when etched in a NaCl solution at 100°C. This critical fluence value also corresponds very well with the fluence at which significant overlap of individual ion tracks occurs.

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.

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.

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