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pelletMoroi, Yuriko*; Kirishima, Akira*; Akiyama, Daisuke*; Sato, Nobuaki*; Kitamura, Akira; Kimuro, Shingo
no journal, ,
Direct disposal of spent nuclear fuel is considered as an alternative option of geological disposal of high level radioactive wastes. In this case, the dissolution speed of uranium should be one of the most important parameter. In this study, the dissolution behavior of UO in the simulated groundwater contains high concentration of carbonate ion was investigated, then, it was revealed that uranium dissolution was promoted by the carbonate ion.
Moroi, Yuriko*; Kirishima, Akira*; Akiyama, Daisuke*; Sato, Nobuaki*; Kitamura, Akira; Kimuro, Shingo
no journal, ,
The technical investigations of direct disposal of spent nuclear fuel are necessary for the progress of back-end strategy, which was affected by the severe accident of Fukushima No.1 Nuclear Power Plant. In this study, the effect of carbonate ion for the leaching of uranium dioxide, which is the main component of spent nuclear fuel, was tested by the batch experiment. The leaching tests carried out in Ar gas atmosphere in glove box and sodium dithionite was used as reductant to simulate the deep underground environment. As a result, the leaching of uranium dioxide was clearly promoted by the carbonate ion. In addition, the dissolution rate of uranium also increased with the concentration of carbonate ion.
pelletMoroi, Yuriko*; Kirishima, Akira*; Akiyama, Daisuke*; Sato, Nobuaki*; Kitamura, Akira; Kimuro, Shingo
no journal, ,
Development of spent nuclear fuel direct disposal system is one of important options in Japan to maintain flexibility of the back-end strategy of nuclear fuel cycle. Other countries like Sweden and Finland advance in research and development of the direct disposal system. However, it is known that some groundwater in Japan contains higher concentration of carbonate ion than that in Sweden or Finland. Therefore, the effect of carbonate ion on the dissolution rate of UO has to be discussed to evaluate feasibility of the direct disposal system in Japan.