Experimental study on elemental behaviors in fluorination of nuclear spent fuel with flame reactor |
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Authors: | Daisuke Watanabe Yuko Kani Akira Sasahira Kuniyoshi Hoshino Fumio Kawamura |
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Affiliation: | 1. Hitachi Research Laboratory, Hitachi Ltd., 7-2-1 Omika-cho, Hitachi-shi, Ibaraki-ken 319-1221, Japan;2. Hitachi Works, Hitachi-GE Nuclear Energy, Ltd., 3-1-1 Saiwai, Hitachi, Ibaraki-ken 317-0073, Japan |
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Abstract: | Our proposed spent nuclear fuel reprocessing technology named FLUOREX is a hybrid system based on reprocessing technologies of fluorination and solvent extraction for light water reactor fuel. In the current research, we experimentally clarified solid–gas transfer behaviours of the fluorides in the FLUOREX process and identified the volatile and non-volatile compounds in the fluorination. We carried out a fluorination experiment for simulated spent nuclear fuel and solid separation from the UF6 gas stream. The distribution ratios of fission product elements in the experimental apparatus were evaluated. Molybdenum, Te, Nb, and Ru were volatilized by fluorination and they accompanied the UF6 gas. However, 22.9% of the Ru and 3.4% of the Nb were retained as solids in the experimental apparatus, contrary to the fact that their partial pressures in the experiment were lower than their vapor pressures. Rubidium, Sr, Zr, Ce, and Nd were completely recovered as solid fluorides, and these results agreed with the prediction based on boiling points of their fluorides. Antimony was completely recovered as a solid; nevertheless, the boiling point of antimony pentafluoride was lower than the process temperature, and that was attributed to the formation of a non-volatile antimony oxyfluoride. |
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Keywords: | reprocessing FLUOREX fluoride volatility method flame reactor spent fuel fission product fluoride UF6 |
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