Structure of the Americium Pyrochlore Am2Zr2O7 and its Evoluation under Alpha Self-Irradiation

Nuclear waste disposal is after safety the main issue of nuclear industry, both in terms of scientific challenge as well as public acceptance. Among the different options that have been envisioned and explored for minor actinides over the past thirty years, two alternatives currently remain: long term disposal in a safe repository or nuclear wastes ¿burning¿ in a so-called transmutation process, both options being generally ultimately related. To fulfill the needs for long-term disposal, geological-time-resistant materials to be employed have to sustain both lixiviation and self-irradiation. This latter should not turn the material into an amorphous one since lixiviation would then be dramatically enhanced. A good knowledge of radiation damages is thus a key prerequisite to select the proper material. In that prospect, we turned our attention on zirconium ceramic oxides, namely pyrochlores of formula An2Zr2O7 (An= actinide), which have been proposed for long term radioactive wastes disposal as well as for transmutation of actinides. Since Am is one of the main long-lived radioactive elements generated in reactors during the fission process, we focused here on studying Am2Zr2O7. Polycrystals were synthesized and a structural analysis by the Rietveld method was followed by an X-ray diffraction study of the effect of a self-irradiation on the structure as a function of time.

BELIN R.C.;  VALENZA P.J.;  RAISON Philippe; 

2009-11-10

Royal Society of Chemistry (RSC)

JRC33995

http://www.springer.com/chemistry/inorganic/book/978-0-85404-678-2,    https://publications.jrc.ec.europa.eu/repository/handle/JRC33995,   

10.1039/9781847555366,