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Gamma decomposition and powder formation of γ - U8Mo nuclear fuel alloys via a hydration – dehydration process / Fábio Branco Vaz de Oliveira in Industrial & engineering chemistry research, Vol. 51 N° 24 (Juin 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 24 (Juin 2012) . - pp. 8237–8245 Titre : Gamma decomposition and powder formation of γ - U8Mo nuclear fuel alloys via a hydration – dehydration process Type de document : texte imprimé Auteurs : Fábio Branco Vaz de Oliveira, Auteur ; Adriano Michael Bernardin, Auteur ; Humberto Gracher Riella, Auteur Année de publication : 2012 Article en page(s) : pp. 8237–8245 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Alloys  Nuclear  fuel Résumé : Gamma uranium–molybdenum alloys have been considered as the fuel phase in plate type fuel elements for material test reactor (MTR) reactors, mainly owing to their acceptable performance under irradiation and metallurgical processing. Regarding their usage as a dispersion phase in aluminum matrix, it is necessary to convert the as cast structure into powder, and one of the techniques considered for this purpose at IPEN/CNEN (Brazil) is by means of the HDH (hydration–dehydration) reactions. This paper shows that, under specific conditions of heating and cooling, hydration–dehydration is sometimes unnecessary, and γUMo fragmentation occurs in a nonreaction predominant mechanism, as shown by the curves of hydrogen absorption/desorption by the gamma uranium–molybdenum alloys as a function of time and temperature. Our focus was on the experimental results presented by the addition of 8% weight molybdenum. Subsequent to their production by induction melting, samples of the alloys were thermally treated under a constant flow of hydrogen for temperatures varying from 500 to 600 °C and for time of 2 to 4 h. The curves relating mass incorporation and time for the above-mentioned temperatures were obtained, and the results were related to the fragmentation. The main conclusion is that, even without a massive hydration–dehydration process, the samples could be fragmented under specific conditions of thermal treatment under the thermal shock phase of the experiments and that there is a strong correlation between absorption and the rate of gamma decomposition or the gamma phase stability of the alloy. In addition, a suggested value of 568.4 °C was obtained for the maximum rate of gamma decomposition, which can also be related to its eutectoid transformation temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202708d [article] Gamma decomposition and powder formation of γ - U8Mo nuclear fuel alloys via a hydration – dehydration process [texte imprimé] / Fábio Branco Vaz de Oliveira, Auteur ; Adriano Michael Bernardin, Auteur ; Humberto Gracher Riella, Auteur . - 2012 . - pp. 8237–8245. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 24 (Juin 2012) . - pp. 8237–8245 Mots-clés : Alloys  Nuclear  fuel Résumé : Gamma uranium–molybdenum alloys have been considered as the fuel phase in plate type fuel elements for material test reactor (MTR) reactors, mainly owing to their acceptable performance under irradiation and metallurgical processing. Regarding their usage as a dispersion phase in aluminum matrix, it is necessary to convert the as cast structure into powder, and one of the techniques considered for this purpose at IPEN/CNEN (Brazil) is by means of the HDH (hydration–dehydration) reactions. This paper shows that, under specific conditions of heating and cooling, hydration–dehydration is sometimes unnecessary, and γUMo fragmentation occurs in a nonreaction predominant mechanism, as shown by the curves of hydrogen absorption/desorption by the gamma uranium–molybdenum alloys as a function of time and temperature. Our focus was on the experimental results presented by the addition of 8% weight molybdenum. Subsequent to their production by induction melting, samples of the alloys were thermally treated under a constant flow of hydrogen for temperatures varying from 500 to 600 °C and for time of 2 to 4 h. The curves relating mass incorporation and time for the above-mentioned temperatures were obtained, and the results were related to the fragmentation. The main conclusion is that, even without a massive hydration–dehydration process, the samples could be fragmented under specific conditions of thermal treatment under the thermal shock phase of the experiments and that there is a strong correlation between absorption and the rate of gamma decomposition or the gamma phase stability of the alloy. In addition, a suggested value of 568.4 °C was obtained for the maximum rate of gamma decomposition, which can also be related to its eutectoid transformation temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202708d