Fases identificables en la zona de interacción de placas combustibles dispersas U3Si2/Al


Matéria (Rio J.)




ABSTRACT Fuel elements based on U3Si2 particles dispersed in a pure Al matrix (known as dispersion fuel element) are known to be very stable under irradiation, in plate type configurations. For this reason, they were or are being used to convert to low enriched uranium a large number of research reactors without significant loss in performance. According to this statement it is perfectly lawful to extend this good irradiation performance to any compound grown by interdiffusion between silicide and Al during the fabrication process. On the other hand, a great effort is being carried out to qualify U(Mo) alloys as higher density fuel. In this sense, plates or miniplates with meats formed by U(Mo) particles dispersed in an Al(Si) matrix are being internationally studied. Post-irradiation examinations performed on plates that underwent satisfactorily irradiation tests were studied taking into account the analysis of plates after fabrication process. As a result it was observed that good irradiation behavior is associated to the formation (during fabrication) of an interaction layer formed by Si-containing phases which surrounds U(Mo) particles. In this work two plates fabricated with U3Si2 particles dispersed in an Al matrix were analyzed by optical and scanning electron microscopies, wave length dispersive microanalysis and x-ray diffraction after fabrication process. The results showed the formation of two phases: U(Al,Si)3 and U3Si2 with modified cell volume. This information would be considered useful, in the U(Mo) qualification process, in order to select Al(Si) matrix that promotes the formation of what can considered “a proper interaction layer”.

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