Effets d'irradiation et comportement des produits de fission dans la zircone et le spinelle

Abstract : Crystalline oxides, such as zirconia (ZrO2) and spinel (MgAl2O4), are promising inert matrices for the transmutation of plutonium and minor actinides. This work deals with the study of the physico-chemical properties of these matrices, more specifically their behaviour under irradiation and their capacity to retain fission products. Irradiations at low energy and incorporation of stable analogs of fission products (Cs, I, Xe) into yttria-stabilized zirconia and magnesium-aluminate spinel single crystals were performed by using the ion implanter IRMA (CSNSM-Orsay). Irradiations at high energy were made on several heavy ion accelerators (GANIL-Caen, ISL-Berlin, HIL-Varsovie). The damage induced by irradiation and the release of fission products were monitored by in situ Rutherford Backscattering Spectrometry experiments. Transmission electron microscopy was also used in order to determine the nature of the damage induced by irradiation. The results show that irradiation of ZrO2 and MgAl2O4 with heavy ions (~ hundred keV and ~ hundred MeV) induces a huge structural damage in crystalline matrices. Total disorder (amorphisation) is however never reached in zirconia, contrary to what is observed in the case of spinel. The results also emphasise the essential role played by the concentration of implanted species on their retention capacity. A dramatic release of fission products was observed when the concentration exceeds a threshold of a few atomic percent. Irradiation of implanted samples with medium-energy noble-gas ions leads to an enhancement of the fission product release. The exfoliation of spinel crystals implanted at high concentration of Cs ions is observed after a thermal treatment at high temperature.
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Material chemistry. Université Paris Sud - Paris XI, 2003. French


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Contributor : Aurelie GENTILS <>
Submitted on : Thursday, November 20, 2003 - 6:36:14 PM
Last modification on : Tuesday, November 29, 2005 - 5:18:27 PM

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Aurélie Gentils. Effets d'irradiation et comportement des produits de fission dans la zircone et le spinelle. Material chemistry. Université Paris Sud - Paris XI, 2003. French. <tel-00003795>

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