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Application of Mechanical Activation to Production of Pyrochlore Ceramic Containing Rare-Earth-Actinide Fraction of HLW.

DE2004825766

Publication Date	2004
Personal Author	Stefanovsky, S. V.; Kirjanova, O. I.
Page Count	12
Abstract	Samples of zirconate pyrochlore ceramic (REE)2(Zr,U)2O7 (REE = La-Gd) containing simulated REE-An fraction of HLW were synthesized by two routes: (1) conventional cold compaction of oxide mixtures in pellets under pressure of 200 MPa and sintering of the pellets at 1550 C for 24 hours; and (2) using preliminary mechanical activation of oxide powders in a linear inductive rotator (LIV-0.5E) and a planetary mill - activator with hydrostatic yokes (AGO-2U) for 5 or 10 min. All the samples sintered at 1550 C were monolithic and dense with high mechanical integrity. As follows from X-ray diffraction (XRD) data, the ceramic sample produced without mechanical activation is composed of pyrochlore as major phase but contains also minor unreacted oxides. The samples prepared from pre-activated mixtures are composed of the pyrochlore structure phase only. Scanning electron microscopy (SEM) data also show higher structural and compositional homogeneity of the samples prepared from mechanically activated batches. The samples produced from oxide mixtures mechanically activated in the LIV for 10 min were slightly contaminated with iron resulting in formation of minor perovskite structure phase not detected by XRD but seen on SEM-images of the samples. Comparison of the samples prepared from non-activated and activated batches showed higher density, lower open porosity, water uptake, and elemental leaching for the samples fabricated from mechanically activated oxide mixtures.
Keywords	Radioactive waste processing High-level radioactive wastes Mechanical vibrations Ceramics Pyrochlore Actinides Sintering Compacting Oxides Partition Waste forms Zirconates Pirconate pyrochlore ceramic(REE)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Mendeleev Inst. Moscow (Russia). Dept. of Chemical Engineering.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200514

Application of Mechanical Activation to Production of Pyrochlore Ceramic Containing Rare-Earth-Actinide Fraction of HLW.

Application of Mechanical Activation to Production of Pyrochlore Ceramic Containing Rare-Earth-Actinide Fraction of HLW.
DE2004825766

Publication Date	2004
Personal Author	Stefanovsky, S. V.; Kirjanova, O. I.
Page Count	12
Abstract	Samples of zirconate pyrochlore ceramic (REE)2(Zr,U)2O7 (REE = La-Gd) containing simulated REE-An fraction of HLW were synthesized by two routes: (1) conventional cold compaction of oxide mixtures in pellets under pressure of 200 MPa and sintering of the pellets at 1550 C for 24 hours; and (2) using preliminary mechanical activation of oxide powders in a linear inductive rotator (LIV-0.5E) and a planetary mill - activator with hydrostatic yokes (AGO-2U) for 5 or 10 min. All the samples sintered at 1550 C were monolithic and dense with high mechanical integrity. As follows from X-ray diffraction (XRD) data, the ceramic sample produced without mechanical activation is composed of pyrochlore as major phase but contains also minor unreacted oxides. The samples prepared from pre-activated mixtures are composed of the pyrochlore structure phase only. Scanning electron microscopy (SEM) data also show higher structural and compositional homogeneity of the samples prepared from mechanically activated batches. The samples produced from oxide mixtures mechanically activated in the LIV for 10 min were slightly contaminated with iron resulting in formation of minor perovskite structure phase not detected by XRD but seen on SEM-images of the samples. Comparison of the samples prepared from non-activated and activated batches showed higher density, lower open porosity, water uptake, and elemental leaching for the samples fabricated from mechanically activated oxide mixtures.
Keywords	Radioactive waste processing High-level radioactive wastes Mechanical vibrations Ceramics Pyrochlore Actinides Sintering Compacting Oxides Partition Waste forms Zirconates Pirconate pyrochlore ceramic(REE)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Mendeleev Inst. Moscow (Russia). Dept. of Chemical Engineering.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200514