Characterization and Radiation Resistance of a Mixed-Alkali Borosilicate Glass for High-Level Waste Vitrification

1999 ◽  
Vol 608 ◽  
Author(s):  
J.M. Roderick ◽  
D. Holland ◽  
C.R. Scales
Keyword(s):  
Borosilicate Glass ◽  
Radiation Resistance ◽  
High Level Waste ◽  
Mixed Alkali ◽  
Waste Vitrification ◽  
High Level

Interactions of Simulated High Level Waste (HLW) Calcine with Alkali Borosilicate Glass

2003 ◽  
Vol 807 ◽  
Author(s):  
S. Morgan ◽  
R. J. Hand ◽  
N. C. Hyatt ◽  
W. E. Lee
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Borosilicate Glass ◽  
Glass Frit ◽  
High Level Waste ◽  
Second Stage ◽  
Mixed Alkali ◽  
High Level ◽  
Simulated High Level Waste ◽  
Fuel Reprocessing

ABSTRACTThis study looks at the interactions between simulated calcined high level waste from fuel reprocessing and mixed alkali borosilicate glass frit in the early stages of melting, and the possibility of the formation of yellow phase during these stages. Simulant “calcine” from a full scale inactive trial (Magnox: oxide “blend” 25:75) was pre-mixed with alkali borosilicate glass, to achieve a 25wt% waste loading, and melted at 1050°C at various times. It is shown that dissolution occurs in two separate stages; the first involves formation of a low density CsLiMoO4 fluid, which separates and forms a yellow/green layer on the surface of the melt, accompanied by some dissolution of rare- earth elements (Nd, Ce, Gd) and Zr from the waste into the glass matrix. The second stage entails more extensive migration of these rare-earth elements into the glass, and the disappearance of the surface layer on the melt. The glass appears more homogenized at the later stages of melting, but still contains undissolved particles of calcine after 16 minutes.

Performance of Borosilicate Glass High-Level Waste Forms in Disposal Systems

1986 ◽  
Vol 73 (2) ◽  
pp. 139-139
Author(s):  
Edward J. Hennelly ◽  
E. I. Du Pont de Nemours
Keyword(s):  
Borosilicate Glass ◽  
High Level Waste ◽  
Waste Forms ◽  
High Level

Affinity Rate Law Failure to Describe Sodium Borosilicate Glass Alteration Kinetics

2003 ◽  
Vol 807 ◽  
Author(s):  
P. Frugier ◽  
S. Gin ◽  
C. Jégou
Keyword(s):  
Borosilicate Glass ◽  
Chemical System ◽  
High Level Waste ◽  
Critical Examination ◽  
Sodium Borosilicate Glass ◽  
Kinetic Rate ◽  
Rate Law ◽  
Passionate Debate ◽  
Experimental Findings ◽  
High Level

ABSTRACTSimplified glass compositions were chosen to improve our knowledge of the alteration kinetics of complex glasses dedicated to the confinement of high-level waste. Since 1998, the sodium borosilicate glass system is at the center of a passionate debate between an affinity-based kinetic rate law and a protective surface layer theory. All the authors who have investigated ternary 68/14/18 SiO2–B2O3–Na2O glass agree on the fact that the affinity law cannot satisfactorily account for its alteration kinetics. Some authors explained that these discrepancies between classical kinetic rate law and experimental findings could be due to macromolecular amorphous separation in the 68/14/18 sodium borosilicate system and that this simplified glass could be divided into 90% reedmergnerite (NaBSi3O8) and 10% diborate (Na2O–2B2O3). This article provides evidence of the homogeneity of ternary 68/18/14 SiO2–B2O3–Na2O glass at nanometric scale and shows that even phase separation at less than nanometric scale could not explain the inability of hydrated glass-solution affinity laws to describe its alteration. The relative simplicity of the SiO2–B2O3–Na2O chemical system allows a critical examination of the macroscopic alteration laws developed over the last twenty years based only on the hydrated glass-solution chemical affinity without taking into account the formation and reactivity of the gel or its passivating properties.

Nepheline Crystallization in High-Alumina High-Level Waste Glass

2015 ◽  
Vol 1744 ◽  
pp. 85-91 ◽  
Author(s):  
José Marcial ◽  
John McCloy ◽  
Owen Neill
Keyword(s):  
Nuclear Waste ◽  
Waste Glass ◽  
High Alumina ◽  
High Level Waste ◽  
Interfacial Conditions ◽  
Waste Vitrification ◽  
Cooling Schedules ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Glass Compositions

ABSTRACTThe understanding of the crystallization of aluminosilicate phases in nuclear waste glasses is a major challenge for nuclear waste vitrification. Robust studies on the compositional dependence of nepheline formation have focused on large compositional spaces with hundreds of glass compositions. However, there are clear benefits to obtaining complete descriptions of the conditions under which crystallization occurs for specific glasses, adding to the understanding of nucleation and growth kinetics and interfacial conditions. The focus of this work was the investigation of the microstructure and composition of one simulant high-level nuclear waste glass crystallized under isothermal and continuous cooling schedules. It was observed that conditions of low undercooling, nepheline was the most abundant aluminosilicate phase. Further undercooling led to the formation of additional phases such as calcium phosphate. Nepheline composition was independent of thermal history.

scholarly journals Design and operating features of the high-level waste vitrification system for the West Valley demonstration project

1986 ◽  
Author(s):  
D.H. Siemens ◽  
M.M. Beary ◽  
S.M. Barnes ◽  
D.N. Berger ◽  
R.A. Brouns ◽  
...  
Keyword(s):  
Demonstration Project ◽  
High Level Waste ◽  
The West ◽  
Waste Vitrification ◽  
High Level

Volatilization of 137Cs and 106Ru from Borosilicate Glass Containing Actual High-Level Waste

1989 ◽  
Vol 72 (8) ◽  
pp. 1438-1441 ◽  
Author(s):  
Hiroshi Kamizono ◽  
Shizuo Kikkawa ◽  
Yoshihiro Togashi ◽  
Shingo Tashiro
Keyword(s):  
Borosilicate Glass ◽  
High Level Waste ◽  
High Level

Evaluation of Cesium Sujcotitanates as an Alternative Waste Form

1996 ◽  
Vol 465 ◽  
Author(s):  
Yali Su ◽  
M. Lou Balmer ◽  
Bruce C. Bunker
Keyword(s):  
Borosilicate Glass ◽  
Thermal Conversion ◽  
Chemical Durability ◽  
Waste Form ◽  
High Level Waste ◽  
Ion Exchangers ◽  
Heat Treated ◽  
High Level ◽  
Excellent Chemical ◽  
Better Than

ABSTRACTSilicotitanate ion exchangers are potential materials for the removal of radioactive Cs and Sr from tank wastes. In this paper the viability of direct thermal conversion of Cs-loaded silicotitanates to an acceptable high level waste form has been examined. Results show that in aqueous solutions, the Cs leach rates of crystalline silicotitanates (heat treated at 800°C) are 0.04, 0.18, 0.4 g/m2day for Cs loadings of 1, 5, and 20 wt%, respectively. Heating the Cs-loaded (up to 20 wt %) silicotitanates at or above 900 °C for 1 hour further reduces the Cs leach rates to approximately zero (beyond the lppm detection limits). Moreover, Cs volatilization was found to be < 0.8 wt% at temperatures as high as 1000 °C. These results suggest that thermally converted silicotitanate ion exchangers exhibit excellent chemical durability (comparable to or better than borosilicate glass) and thus, have great potential as an alternative waste form.

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