Helium behaviour in stoichiometric and hyper-stoichiometric UO₂

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• 作者：Z. Talip ; T. Wiss ; E.-A. Maugeri ; J.-Y. Colle ; P.-E. Raison ; E. Gilabert ; M. Ernstberger ; D. Staicu ; R.J.M. Konings
• 关键词：UO2 ; Hyper-stoichiometric UO2 ; U3O8 ; Helium ; Diffusion
• 刊名：Journal of the European Ceramic Society
• 出版年：May, 2014
• 年：2014
• 卷：34
• 期：5
• 页码：1265-1277
• 全文大小：3388 K

文摘

Understanding the long-term behaviour of the UO₂ spent fuel in terms of helium build-up and oxidation is a very important issue for safety aspects of storage and disposal. Although helium behaviour in stoichiometric UO₂ has been studied by many authors, it has not been well established and there is a lack of experimental studies in non-stoichiometric UO₂. In this study, an infusion technique was chosen to introduce helium in stoichiometric and hyperstoichiometric single and polycrystalline UO₂ and polycrystalline U₃O₈ samples. Characterization of the samples before and after infusion and after thermal desorption measurements were performed by thermogravimetry, X-ray diffraction, laser flash technique and scanning electron microscopy. It was observed that the increase of stoichiometry in UO₂ affects barely the dissolved helium quantity (under the same infusion conditions as in stoichiometric), while it has a more pronounced influence on the helium diffusion. These two effects are much more pronounced for U₃O₈.