Effects of fission product incorporation on the microstructure of cubic zirconia

Cesium, iodine and strontium ions have been implanted into yttria-stabilized cubic zirconia (YSZ) to determine the effects of fission product incorporation in YSZ that is considered as an inert nuclear fuel matrix. The ion implantation was conducted at room temperature to 1×1021 ions/m2 for each ion with ion energies ranging from 70 to 400 keV. The peak displacement damage level and the peak ion concentration in YSZ reached 205–330 displacement per atoms (dpa) and 11–26 at.%, respectively. The microstructure of the implanted YSZ was studied by in situ and cross-sectional transmission electron microscopy (TEM). In the iodine and strontium implanted samples, a damaged layer with a high density of defect clusters was observed, while in the cesium implanted specimen, most of the damaged layer is amorphous.Nanocrystalline precipitates were observed in the strontium implanted specimen after annealing at 1273 K. The results are discussed in terms of the ionic size, mobility and the solubility of the implanted species in YSZ.