Aqueous alteration of VHTR fuels particles under simulated geological conditions

Abstract : Very High Temperature Reactor (VHTR) fuels consist of the bistructural-isotropic (BISO) or tristructural-isotropic (TRISO)-coated particles embedded in a graphite matrix. Management of the spent fuel generated during VHTR operation would most likely be through deep geological disposal. In this framework we investigated the alteration of BISO (with pyrolytic carbon) and TRISO (with SiC) particles under geological conditions simulated by temperatures of 50 and 90 C-circle and in the presence of synthetic groundwater. Solid state (scanning electron microscopy (SEM), micro-Raman spectroscopy, electron probe microanalyses (EPMA) and X-ray photoelectron spectroscopy (XPS)) and solution analyses (ICP-MS, ionique chromatography (IC)) showed oxidation of both pyrolytic carbon and SiC at 90 C-circle. Under air this led to the formation of SiO2 and a clay-like Mg silicate, while under reducing conditions (H-2/N-2 atmosphere) SiC and pyrolytic carbon were highly stable after a few months of alteration. At 50 C-circle, in the presence and absence of air, the alteration of the coatings was minor. In conclusion, due to their high stability in reducing conditions, HTR fuel disposal in reducing deep geological environments may constitute a viable solution for their long-term management. (C) 2014 Elsevier B.V. All rights reserved.
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Article dans une revue
Journal of Nuclear Materials, Elsevier, 2014, 448 (1-3), pp.206-216. 〈10.1016/j.jnucmat.2014.01.049〉
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Soumis le : mardi 29 septembre 2015 - 17:00:52
Dernière modification le : mardi 24 juillet 2018 - 08:34:01

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Abdelouahed Ait Chaou, Abdesselam Abdelouas, Gökhan Karakurt, Bernd Grambow. Aqueous alteration of VHTR fuels particles under simulated geological conditions. Journal of Nuclear Materials, Elsevier, 2014, 448 (1-3), pp.206-216. 〈10.1016/j.jnucmat.2014.01.049〉. 〈hal-01206900〉

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