Experimental study of the diffusion of Xe and Kr implanted at low concentrations in UO2 and determination of their trapping mechanisms

JOURNAL OF NUCLEAR MATERIALS

卷:556

Article

Gerardin, M.^1,2  Gilabert, E.³  Horlait, D.³  Barthe, M-f.⁴  Carlot, G.¹ 

[1] CEA, DEN, DEC, F-13108 St Paul Les Durance, France

[2] Univ Lorraine, CNRS, GeoRessources, F-54000 Nancy, France

[3] Univ Bordeaux, CNRS, CENBG IN2P3, F-33170 Gradignan, France

[4] Univ Orleans, CNRS, CEMHTI, 3A Rue Ferollerie, F-45071 Orleans 2, France

关键词: Uranium dioxide;    Rare gases;    Diffusion;    Modelling;    Ion implantation;    Radiation induced defects;   

DOI  :  10.1016/j.jnucmat.2021.153174

来源: Elsevier

【 摘 要 】

The fission of uranium dioxide produces gaseous elements degrading nuclear fuel properties. A thorough understanding of the transport and release of gaseous products is thus essential. The present work focuses on xenon and krypton migration mechanism in uranium dioxide. Desorption experiments on ion implanted UO2 were performed at 1300 degrees C. Xe and Kr releases were simulated using a mesoscale model that was developed taking into account single gas atom diffusion and defect traps. We showed that the defects have a high influence on Xe and Kr migration mechanisms and therefore have to be considered to accurately determine diffusion coefficients. We evaluated the diffusion coefficient of Xe and Kr at (1.73 +/- 0.15)x10(-20) m(2)/s at 1300 degrees C and we showed that the diffusion of rare gases is subjected to two trapping mechanisms. The first occurs during the ion implantation and the second during high-temperature annealings. The nature of the trapping sites is discussed in the light of the literature on radiation induced defects. This study also consolidates the use of non activated UO2 implanted with heavy ions as a less-hazardeous substitute for irradiated UO2. (C) 2021 Elsevier B.V. All rights reserved.

【 授权许可】

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