Fabrication, chemical and thermal stability studies of crystalline ceramic wasteform based on oxyapatite phosphate host LaSr4(PO4)3O for high level nuclear waste immobilization

2020 ◽  
Vol 394 ◽  
pp. 122552
Author(s):  
Ramya Ravikumar ◽  
Buvaneswari Gopal ◽  
Hrudananda Jena
Keyword(s):  
Thermal Stability ◽  
Nuclear Waste ◽  
Stability Studies ◽  
Waste Immobilization ◽  
High Level Nuclear Waste ◽  
Crystalline Ceramic ◽  
Nuclear Waste Immobilization ◽  
High Level

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.

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.

In Situ Radiation Damage Studies of Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12

2008 ◽  
Vol 1124 ◽  
Author(s):  
Karl R Whittle ◽  
Mark Blackford ◽  
Gregory R Lumpkin ◽  
Katherine L Smith ◽  
Nestor J Zaluzec
Keyword(s):  
Nuclear Waste ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Voltage Electron ◽  
Significant Difference ◽  
User Facility ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

AbstractGarnets, A3B2C3O12, are considered to be potential host phases for the immobilization of high-level nuclear waste as they can accommodate a number of elements of interest, including Zr, Ti and Fe. The naturally occurring garnet, kimzeyite, Ca3(Zr,Ti)2(Si,Al,Fe)3O12, can contain ˜30wt% Zr. An understanding of the radiation tolerance of these materials is crucial to their potential use in nuclear waste immobilization. In this study two synthetic analogues of kimzeyite of composition Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 were monitored in situ during irradiation with 1.0 MeV Kr ions using the intermediate voltage electron microscope-Tandem User Facility (IVEM) at Argonne National Laboratory. The structure of these materials was previously determined by neutron diffraction and 57Fe Mössbauer spectroscopy. Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 have very similar structural properties with cubic Ia3d symmetry, the only significant difference being the presence of Zr and Hf, respectively, on the 6 coordinated B sites.

Radiation Effects in Silicate Glasses - A Review

1988 ◽  
Vol 125 ◽  
Author(s):  
Ned E. Bibler ◽  
David G. Howitt
Keyword(s):  
Fiber Optics ◽  
Nuclear Waste ◽  
Radiation Effects ◽  
Alpha Particles ◽  
Phase Changes ◽  
Silicate Glasses ◽  
Atomic Displacements ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

ABSTRACTThe study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as high level nuclear waste immobilization and fiber optics. Radiation changes the properties of these glasses by altering their electronic and atomic configurations. These alterations or defects may cause dilatations or microscopic phase changes along with absorption centers that limit the optical application of the glasses. Atomic displacements induced in the already disordered structure of the glasses may affect their use where heavy irradiating particles such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may result. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions.In this paper, we review the literature concerning radiation effects on density, durability, stored energy, microstructure and optical properties of silicate glasses. Both simple glasses and complex glasses used for immobilization of nuclear waste are considered.

Materials Science of High-Level Nuclear Waste Immobilization

MRS Bulletin ◽  
2009 ◽  
Vol 34 (1) ◽  
pp. 46-53 ◽  
Author(s):  
William J. Weber ◽  
Alexandra Navrotsky ◽  
Sergey Stefanovsky ◽  
Eric R. Vance ◽  
Etienne Vernaz
Keyword(s):  
Nuclear Waste ◽  
Materials Science ◽  
Fuel Cycle ◽  
Ceramic Composites ◽  
Nuclear Wastes ◽  
Waste Streams ◽  
Waste Immobilization ◽  
Technical Challenges ◽  
Nuclear Waste Immobilization ◽  
High Level

AbstractWith the increasing demand for the development of nuclear power comes the responsibility to address the issue of waste, including the technical challenges of immobilizing high-level nuclear wastes in stable solid forms for interim storage or disposition in geologic repositories. The immobilization of high-level nuclear wastes has been an active area of research and development for over 50 years. Borosilicate glasses and complex ceramic composites have been developed to meet many technical challenges and current needs, although regulatory issues, which vary widely from country to country, have yet to be resolved. Cooperative international programs to develop advanced proliferation-resistant nuclear technologies to close the nuclear fuel cycle and increase the efficiency of nuclear energy production might create new separation waste streams that could demand new concepts and materials for nuclear waste immobilization. This article reviews the current state-of-the-art understanding regarding the materials science of glasses and ceramics for the immobilization of highlevel nuclear waste and excess nuclear materials and discusses approaches to address new waste streams.

Instantaneous Formation of Synroc-B Phases at Ambient Pressure

1995 ◽  
Vol 412 ◽  
Author(s):  
J. M. Mchale ◽  
N. V. Coppa
Keyword(s):  
Nuclear Waste ◽  
Ambient Pressure ◽  
Nuclear Materials ◽  
Phase Assemblage ◽  
Preparation Conditions ◽  
Nitrate Precursor ◽  
Freeze Dried ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

AbstractThe titanate based nuclear waste immobilization medium, Synroc-B, has been synthesized at atmospheric pressure from freeze dried nitrate precursors. Complete formation of the phase assemblage (CaTiO3, CaZrTi2O7, and BaAl2Ti5O14) occurred upon calcination of the nitrate precursor after only 10 minutes at 1100°C. This improvement in the preparation conditions may lead to practical application of the material in the safe disposal of high level nuclear waste and the immobilization of other strategic nuclear materials.

Nuclear waste immobilization into structure of zirconolite by Complex Sol Gel Process

2014 ◽  
Vol 1683 ◽  
Author(s):  
Tomasz Smoliński ◽  
Andrzej Deptuła ◽  
W. Lada ◽  
Tadeusz Olczak ◽  
Andrzej G. Chmielewski ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Nuclear Waste ◽  
Thermal Analyses ◽  
Sol Gel ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

ABSTRACTZirconolite (CaZrTi2O7) is one of the components of Synroc materials, which are regarded throughout the world nuclear as the second generation of high-level nuclear waste forms. The zirconolite phase was synthesized by a sol-gel method, with one variant of the method making use of ascorbic acid as a strong complexing agent. Into the structure of the zirconolite was incorporated 10 mol% Sr. Undoped and doped samples were examined by thermal analyses and X-ray diffraction. Addition of ascorbic acid to the sols lowered the firing temperature and promoted formation of the zirconolite phase.

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