scholarly journals Vitreous Materials for Nuclear Waste Immobilisation and IAEA Support Activities

MRS Advances ◽  
2016 ◽  
Vol 1 (63-64) ◽  
pp. 4201-4206 ◽  
Author(s):  
Rebecca A. Robbins ◽  
Michael I. Ojovan
Keyword(s):  
Radioactive Waste ◽  
Nuclear Waste ◽  
Chemical Elements ◽  
Phosphate Glasses ◽  
Waste Vitrification ◽  
Waste Immobilization ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level ◽  
High Degree

ABSTRACTVitreous materials are the overwhelming world-wide choice for the immobilisation of HLW resulting from nuclear fuel reprocessing due to glass tolerance for the chemical elements found in the waste as well as its inherent stability and durability. Vitrification is a mature technology and has been used for high-level nuclear waste immobilization for more than 50 years. Borosilicate glass is the formulation of choice in most applications although other formulations are also used e.g. phosphate glasses are used to immobilize high level wastes in Russia. The excellent durability of vitrified radioactive waste ensures a high degree of environment protection. Waste vitrification gives high waste volume reduction along with simple and cheap disposal facilities. Although vitrification requires a high initial investment and then operational costs, the overall cost of vitrified radioactive waste is usually lower than alternative options when account is taken of transportation and disposal expenses. Glass has proven to be also a suitable matrix for intermediate and low-level radioactive wastes and is currently used to treat legacy waste in USA, and NPP operational waste in Russia and South Korea. This report is also outlining IAEA activities aiming to support utilisation of vitreous materials for nuclear waste immobilisation.

Chemical structure and dissolution behaviour of CaO and ZnO containing alkali-borosilicate glass

2022 ◽  
Author(s):  
Adam J Fisher ◽  
Hao Ding ◽  
Prashant Rajbhandari ◽  
Brant Walkley ◽  
Lewis R Blackburn ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Chemical Structure ◽  
Sodium Borosilicate Glass ◽  
Waste Vitrification ◽  
Dissolution Behaviour ◽  
High Level Nuclear Waste ◽  
High Level

Within the context of the UK’s radioactive waste vitrification programme, which utilises a lithium-sodium borosilicate glass modified with CaO and ZnO to immobilise high level nuclear waste, an investigation was...

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.

Product Models for the Vitrification of West Valley High-Level Wastes

1988 ◽  
Vol 127 ◽  
Author(s):  
I. L. Pegg ◽  
E. E. Saad ◽  
X. Feng ◽  
R. B. Adiga ◽  
W. P. Freeborn ◽  
...  
Keyword(s):  
Process Model ◽  
Process Variations ◽  
Product Performance ◽  
Borosilicate Glasses ◽  
The West ◽  
Product Models ◽  
Waste Immobilization ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

ABSTRACTProperty models have been developed for the major properties that need to be controlled in the production of borosilicate glasses for West Valley high-level nuclear waste immobilization. The chemical durability is the most important parameter for product performance, while melt viscosity is the most critical parameter in assuring the processability of the glass. Simple models for these properties are described that are based on data from numerous glasses which were prepared with compositions in the region around the West Valley reference glass. A scheme for optimization of the target glass and for predicting the acceptability of glasses resulting from natural process variations is illustrated. This involves integration of the product models with a process model that was described previously. This approach has guided the present placement of the West Valley reference glass.

TEM Study of Short-Range-Order in Zirconolite Induced by High Temperature Ion Irradiation

1999 ◽  
Vol 5 (S2) ◽  
pp. 756-757
Author(s):  
S. X. Wang ◽  
L. M. Wang ◽  
R. C. Ewing
Keyword(s):  
Oxygen Vacancies ◽  
Ion Irradiation ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
Waste Immobilization ◽  
Temperature Irradiation ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
Shortrange Order ◽  
High Level

Zirconolite (CaZrTi207) is an important phase proposed for high level nuclear waste immobilization. Zirconolite was irradiated by 1 MeV Kr+ at various temperatures. At room temperature, zirconolite became amorphous after a dose of 7x1014 ions/cm2.1 Amorphization dose increased with temperature due to thermal annealing. The critical temperature, above which amorphization does not occur, was estimated to be 654 K. During the low temperature irradiation (<654 K), concurrent with amorphization, zirconolite transformed from a monoclinic structure to the cubic pyrochlore structure and then to the fluorite substructure. The structural change is due to the disordering between cations and between oxygen and oxygen vacancies.After an irradiation at 673 K to a dose of 3.6x1015 ions/cm, the zirconolite samples remained crystalline. The diffraction pattern consists of strong maxima from the fluorite structure and diffuse maxima surrounding the Bragg positions of the pyrochlore superlattice (FIG. 1). Diffuse scattering patterns have been reported in other phases, and were generally attributed to the shortrange- order (SRO) domains.

Corrosion of inconel-690 electrodes in waste glass melts

1999 ◽  
Vol 556 ◽  
Author(s):  
H. Gan ◽  
A. C. Buechele ◽  
C.-W. Kim ◽  
X. Huang ◽  
R. K. Mohr ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Glass Composition ◽  
Waste Glass ◽  
Savannah River ◽  
Glass Melts ◽  
Waste Vitrification ◽  
Inconel 690 ◽  
Ac Current ◽  
High Level Nuclear Waste ◽  
High Level

AbstractInconel-690, a Cr-Ni-Fe-based “superalloy,” has become the material of choice for electrodes in joule-heated waste glass melters and is currently employed in the high-level nuclear waste vitrification systems at West Valley and DWPF, as well as in GTS Duratek's privatized M-Area mixed waste vitrification facility at Savannah River. Future applications of joule-heated vitrification technologies will necessitate an assessment of the limits of performance of this material under more demanding conditions than have been studied previously. In this work, Inconel 690 electrodes were tested in several simulated sodium-rich aluminosilicate waste glasses in wide ranges of AC current density, electrical waveform, temperature, and glass composition.

Non-Linearity in Glass Composition Dependence of Dissolution Rates: Effect of Solution pH

1993 ◽  
Vol 333 ◽  
Author(s):  
Shi-Ben Xing ◽  
Isabelle S. Muller ◽  
Ian L. Pegg
Keyword(s):  
Nuclear Waste ◽  
Glass Composition ◽  
Ph Dependence ◽  
Solution Ph ◽  
Ph Values ◽  
Waste Vitrification ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Soluble Components ◽  
Glass Compositions

ABSTRACTIn our previous studies on the optimization of glass compositions for high-level nuclear waste vitrification it was found that, over certain composition ranges, PCT leachate concentrations increased dramatically with very small changes in glass composition. The large differences that are observed between the leachate pH values for the “durable” and the “less-durable” glasses is one possible cause for this strongly non-linear glass composition effect; conversely, the pH difference may be merely another symptom. In this study, four simulated nuclear waste glasses (two of the less-durable and two of the durable types), were leached in both zwitterionic and inorganic buffer solutions, at fixed pH-values in the ranges of 7 to 12. The very different leaching behaviors of the two types of glasses persisted and, furthermore, different pH-dependence was found despite their very similar glass composition. This study suggests that the leachate pH difference observed between the less-durable and the durable glasses under uncontrolled pH conditions is not the major cause of the large difference of leaching behavior between those glasses. The normalized release ratios of soluble components (B, Li, Na) to Si show significant differences for the two types of glasses.

Sign in / Sign up

Export Citation Format

Share Document