Novel approaches for the in situ study of the sintering of nuclear oxide fuel materials and their surrogates
Résumé
Sintering is one of the key-point of the processing of ceramic materials. It is then of
primary interest for the nuclear fuel cycle, in which it constitutes an important step in the
fabrication of either UO2 or (U,Pu)O2 pellets used in current PWR reactors. The sintering of
actinides oxides not only drives the final density and microstructure of the fuels, but also
several characteristics that can impact significantly their behavior in the reactor. Dedicated
tools are then needed to monitor the microstructure of such materials and forecast their
evolution. In this frame, this paper presents the new potentialities offered by the use of
environmental scanning electron microscope at high temperature (HT-ESEM) for the study of
nuclear ceramics sintering.
First, the results obtained from bulk pellets are detailed, either regarding original
fundamental data at the grain level (such as grain boundaries and pores motion), or design of
dedicated microstructures through the assessment of grain growth kinetics. Acquisition of
sintering maps thanks to the combination of HT-ESEM observations and classical
dilatometric measurements are also addressed. In a second part, observations undertaken at
the 2-grain scale to monitor the first stage of sintering, dedicated to neck elaboration, are
presented, and compared to the results currently provided by numerical models.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
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