Thermal behaviour of caesium implanted in UO2: A comparative study with the xenon behaviour

JOURNAL OF NUCLEAR MATERIALS

卷:543

Article

Panetier, C.¹  Pipon, Y.^1,2  Gaillard, C.¹  Moncoffre, N.¹  Wiss, T.³  Mangin, D.⁴  Dieste, O.³  Marchand, B.¹  Ducher, R.⁵  Dubourg, R.⁵  Epicier, T.⁶  Raimbault, L.⁷ 

[1] Univ Claude Bernard Lyon 1, Univ Lyon, UMR 5822, CNRS IN2P3,IP2I Lyon, 4 Rue Enrico Fermi, F-69622 Villeurbanne, France

[2] Univ Lyon, Dept Chim, UCBL, IUT Lyon 1, F-69622 Lyon, France

[3] European Commiss, DG Joint Res Ctr, Directorate Nucl Safety & Secur G, POB 2340, D-76125 Karlsruhe, Germany

[4] Univ Lorraine, IJL, CNRS UMR7198 CS 14234, F-54042 Nancy, France

[5] IRSN, LETR, BP3, F-13115 St Paul Les Durance, France

[6] Univ Claude Bernard Lyon 1, Univ Lyon, INSA Lyon, CLYM,MATEIS,UMR CNRS 5510, 7,Ave Jean Capelle, F-69621 Villeurbanne, France

[7] PSL Res Univ, MINES ParisTech, Ctr Geosci, 35 Rue St Honore, F-77305 Fontainebleau, France

关键词: UO2;    SIMS;    TEM;    Cs;    Xe;    bubbles;   

DOI  :  10.1016/j.jnucmat.2020.152520

来源: Elsevier

【 摘 要 】

Xenon and caesium are among the most impacting fission products when studying the nuclear fuel: xenon for its role on the fuel rod thermomechanical behaviour during reactor operation and caesium in the case of atmospheric radioactive release during an accident in a nuclear power plant. This paper focuses on the comparison of caesium and xenon thermal behaviour in polycrystalline uranium dioxide (UO2) pellets. Caesium-133 or xenon-136 stable isotopes were introduced in depleted UO2 samples by ion implantation at a maximum concentration of 0.08 at% at a depth of around 140 nm below the sample surface. Annealing under reducing atmosphere (Ar/H-2 5 %) was performed at 1000 degrees C or 1600 degrees C, which corresponds respectively to a representative temperature during nuclear reactor operation (at the centre of the fuel pellets) and during an accident. The caesium migration in UO2 was investigated by Secondary Ion Mass Spectrometry and compared to the thermal behaviour of xenon in UO2 at 1600 degrees C. Transmission Electron Microscopy was performed in order to characterise UO2 microstructure before and after annealing. The results indicate that caesium has a different behaviour than xenon with which it is often compared for its release from the nuclear fuel. In particular, we highlight a difference between the growth kinetics of caesium and of xenon bubbles at 1600 degrees C which can be correlated to the availability of thermal vacancies in UO2 and to the different ability of Xe and Cs atoms for thermal resolution. (C) 2020 Elsevier B.V. All rights reserved.

【 授权许可】

Free