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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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Bonding xenon and krypton on the surface of uranium dioxide single crystal

Dąbrowski L., Szuta M.

Nukleonika

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2014

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Vol. 59, No. 3

83--89

EN

We present density functional theory (DFT) calculation results of krypton and xenon atoms interaction on the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalised gradient approximation (GGA) was applied using the ABINIT program package. To compute the unit cell parameters, the 25 atom super-cell was chosen. It has been revealed that close to the surface of a potential well is formed for xenon and krypton atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of ab initio calculations in adiabatic approximation. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown that the potential well for the oxygenic surface is deeper than for the metallic surface. The thermal stability of immobilising the atoms of krypton and xenon in the potential wells were evaluated. The results are shown in graphs.

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Bonding xenon on the surface of uranium dioxide single crystal

Dąbrowski L., Szuta M.

Nukleonika

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2013

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Vol. 58, No. 4

453--458

EN

We present density functional theory (DFT) calculation results of xenon atom interaction with the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalized gradient approximation (GGA) was applied using the ABINIT program package. It has been revealed that close to the surface a potential well is formed for xenon atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of “ab initio” calculations. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown, that the potential well for the oxygenic surface is deeper than for the metallic surface.

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Ageing of ceramics under a temperature gradient.

Ruello P., Petot C., Petot-Ervas G.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

790-791

EN

This paper reviews the conditions leading to a kinetic demixing process in semiconducting and ionic compounds. Experimental results for CoO, MgO, uranium dioxide and yttria-doped zirconia samples are reported.