Study on the Zirconolite Solidification of Simulated Np/Pu Radioactive Incineration Ash |
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| Institution: | ;1.Institute of Nuclear and New Energy Technology;2.Tsinghua University |
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| Abstract: | High level waste is nuclear energy generated during the application process ,which is the greatest and the most difficult to management the waste. Proper treatment and disposal of it has already become a worldwide problem, and has become one of the key factors of restricting nuclear energy for sustainable development. Zirconolite (CaZrTi2O7) is one of the most stable mineral on the Earth and actinide major parasitic phase, therefore, it is widely used to solidify actinides separated from high level radioactive waste. In this paper, the zirconolite solid solution was synthesized by high temperature solid-stated method using a particular composition of simulated Np/Pu radioactive incineration ash (SRIA). The phase composition has been investigated by X-ray diffraction (XRD), the calcined temperature gained according to thermogravimetry scanning calorimeter (TG-DSC) analysis. Anti-leaching performance has also been researched with MCC-1 method. Results show that CaZrTi2O7 can load 40% SRIA, the accumulated leaching fraction of Ca is only about 10-4 cm in 28 days at 90 ℃, the concentrations of Zr , Ti and other noble metal ions were all less than detectability of ICP-MS, the leaching rate , normalization leaching rate, and accumulated leaching fraction of all Zr , Ti and other noble ions were 10-8 cm/d, 10-8 g/cm2·d and 10-7 cm, the results indicate that the zirconolite solidification has excellent chemical durability. |
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