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Synthesis and Characterization of Co-Cs-Nd-Sr-Doped Perovskite-Rutile-Type Structure

Smolinski T., Zhao L., Rogowski M., Wawszczak D., Olczak T., Brykala M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1417--1423

EN

The perovskite type matrix is considered as solidification material for high-level radioactive waste. In this work the perovskite-rutile-type matrix doped by Co, Cs, Nd and Sr which simulate nuclear waste was prepared by sol-gel route. The material was characterized by several methods such as: X-ray diffraction, energy dispersive X-ray spectrometer, and particle induced X-ray emission combined with Rutherford backscattering spectrometry. The analyzes confirmed chemical composition Co-Cs-Nd-Sr-doped perovskite-rutile-type structure. A virtual model of the pellet`s structure was created non-destructively by Roentgen computed micro-tomography. The leaching tests confirmed high chemical resistance of the matrix.

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Microspheres and Pellets of UO2 Prepared Via ADU by Complex Sol-Gel Process and ICHTJ Process

Brykala M., Rogowski M., Wawszczak D., Olczak T., Smolinski T.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1397--1404

EN

This study is devoted to synthesis and characterization of uranium dioxide microspheres (Ø < 100 μm) and pellets by application of powder-free process called the Complex Sol-Gel Process. The precursors of prepared sols were ascorbic acid solution with dissolved a freshly precipitated ammonium diuranate. The microspheres of uranyl-ascorbate gel were obtained using the ICHTJ Process. The pellets were formed by pressing and sintering of uranium dioxide powder. Studies allowed determining an optimal heat treatment of calcination, reduction and sintering processes at temperatures of 700°C, 900°C and 1300°C, respectively. The main parameters which play a key role in the process of synthesis method and features of the pellets and microspheres of uranium dioxide are described in this article.

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Carbonization of solid uranyl-ascorbate gel as an indirect step of uranium carbide synthesis

Brykala M., Rogowski M., Olczak T.

Nukleonika

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2015

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Vol. 60, No. 4, part 2

921--925

EN

The studies of the synthesis of uranium carbide from uranyl-ascorbate gels using the complex sol-gel process (CSGP) have been carried out. The synthesis of uranyl-ascorbate mixture as liquid sol from uranium trioxide and ascorbic acid and solid gel by extraction of water from sol were carefully examined. Ascorbic acid was used as a complexing agent in complex sol-gel process and as a carbon source. The crucial step to obtain final uranium carbides from the aforementioned substrates is the carbonization process. The thermal behavior of ascorbic acid and uranyl-ascorbate gels in a nitrogen atmosphere in the temperature range of 25–900°C were investigated using TG-DTG. Furthermore, the products of the carbonization of uranyl-ascorbate gels in nitrogen, argon and vacuum atmosphere were identifi ed by X-ray diffraction. TG-DTG was used also as a method for determining of carbon residues in the samples.