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[摘要]：The recycling and reuse of uranyl salt solutions produced from the acid dissolution of spent nuclear fuels is of particular interest for the reprocessing of nuclear fuels. The ability to utilize these dissolved salts as precursors for bulk UO(2) defines a materials pathway for the reduction of nuclear waste destined for long-term repository storage. We present a room temperature (RT) synthesis of uranium dioxide nanoparticles (NPs) in acidic solutions, whose small size and uniform shape allow for dramatic decreases in sintering temperature. Gamma irradiation is a valuable method for the synthesis of a wide range of metal-based NPs. Here it has been successfully used to form (depleted) uranium oxide (d-UO(2)) NPs. In particular, this study focuses on the reaction dependency of solution pH and reaction dose on the shapes, sizes, yield, and properties of the products. The thermal stability and sintering behavior of the d-UO(2) NPs is studied utilizing transmission electron microscopy (TEM) with an in situ heating stage. These d-UO2 NPs exhibit sintering temperatures in the range of 500 degrees C-600 degrees C, which is between 700-1000 degrees C lower than reported bulk UO(2) sintering temperatures. Detailed characterization results from UV-vis spectroscopy, TEM, and in situ heating stage TEM are presented for the reaction solutions, the RT NP products, and the sintered NPs. |
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