Electron microscopy characterization of the fuel-cladding interaction in medium burnup annular fast reactor MOX

JOURNAL OF NUCLEAR MATERIALS

卷:551

Article

Cappia, F.¹  Winston, A.¹  Miller, B.¹  Kombaiah, B.¹  Teng, F.¹  Murray, D.¹  Frazer, D.¹  Harp, J. M.² 

[1] Idaho Natl Lab, Characterizat & Adv Post Irradiat Examinat Div, POB 1625, Idaho Falls, ID 83415 USA

[2] Oak Ridge Natl Lab, Reactor & Nucl Syst Div, POB 2008, Oak Ridge, TN 37831 USA

关键词: Sodium fast reactors;    Annular MOX;    HT-9 cladding;    FCCI;    SEM;    TEM;   

DOI  :  10.1016/j.jnucmat.2021.152922

来源: Elsevier

【 摘 要 】

In this work, we present electron microscopy data focused on the fuel-cladding interaction layer in annular fast reactor MOX with HT-9 cladding at medium burnup. In agreement with previous literature data, the volatile fission products Cs, Te and I have migrated radially into the extreme fuel periphery and partially interacted with the cladding. The accumulation of Cs has occurred in the outermost rim of the fuel pellet, where grain recrystallization has also been observed. Significant amounts of Pd have been found in the interaction zone, particularly in the sample taken from the upper half of the fissile column where the cladding temperatures are higher. At this axial location, Cr has been enriched at the cladding inner surface and diffused into the fuel. Chromium remains mainly in metallic form, but locally formed oxides. The fission products Cs, Te and I are found, with variable composition, in form of nanocrystalline regions dispersed in the metallic Cr-rich layer. The morphology and chemical characteristics of the layer suggest a non-oxidative corrosion mechanism as principal cladding degradation phenomenon occurring in this sample, with local onset of Cr oxidation within the nanocrystalline precipitates. (c) 2021 Elsevier B.V. All rights reserved.

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