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To simulate self-irradiation effects of nuclear waste forms in long period of deep geological disposal, Gd2Ce2O7 as simulated An4+ matrix was chosen to be irradiated using 0.5 MeV alpha ions to fluences ranging from 1 × 1015 to 1 × 1017 ions cm−2. Irradiation-induced structural change and microstructural evolution were examined using grazing incidence X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Lattice swelling and amorphization in irradiated layer indicated an enhanced disordering degree with increased ion fluences. Main Raman peaks broaden and intensity decrease indicated a significant bonds distortion. In addition, no element aggregation about Gd, Ce and O occurs after He2+ irradiation. [ABSTRACT FROM AUTHOR]

In this paper, a sol-spray pyrolysis route was employed to fabricate (Cs, Ba)-hollandite ceramic waste forms. The high-phase purity (Cs0.8−xBa0.4+x)(Al1.6+xTi6.4−x)O16 (0 ≤ x ≤ 0.4) ceramics were synthesized at 1050 °C using the produced powders by sol-spray pyrolysis. The results show that all samples show tetragonal hollandite with rod morphology. Additionally, the sintered (Cs, Ba)-hollandite ceramics exhibit a good chemical durability. The normalized release rates of Cs and Ba were < 10−2 g m−2 d−1 after 14 days. These results indicate that hollandite ceramics are promising candidate for immobilizing radioactive cesium. [ABSTRACT FROM AUTHOR]