Recovery of uranium from (U,Gd)O sub(2) nuclear fuel scrap using dissolution and precipitation in carbonate media

• Published in: Journal of nuclear materials 2011-11, Vol.418 (1-3), p.93-26
• Main Authors: Kim, Kwang-Wook, Hyun, Jun-Taek, Lee, Eil-Hee, Park, Geun-Il, Lee, Kune-Woo, Yoo, Myung-June, Song, Kee-Chan, Moon, Jei-Kwon, Yoshida, Keita, Arima, Tatsumi, Inagaki, Yaohiro, Idemitsu, Kazuya, Osaka, Masahiko, Miwa, Shuhei
• Format: Article
• Language: English
• ISSN: 0022-3115
• DOI: 10.1016/j.jnucmat.2011.06.019

This work studied a process to recover uranium from contaminated (U,Gd)O sub(2) scraps generated from nuclear fuel fabrication processes by using the dissolution of (U,Gd)O sub(2) scraps in a carbonate with H sub(2)O sub(2) and the precipitation of the dissolved uranium as UO sub(4). The dissolution characteristics of uranium, Gd, and impurity metal oxides were tested, and the behaviors of UO sub(4) precipitation and Gd solubility were evaluated with changes of the pH of the solution. A little Gd was entrained in the UO sub(4) precipitate to contaminate the uranium precipitate. Below a pH of 3, the uranium dissolved in the form of uranyl peroxo-carbonato complex ions in the carbonate solution was precipitated as UO sub(4) with a high precipitation yield, and the Gd had a very high solubility. Using these characteristics, the Gd-contaminated UO sub(4) could be purified using dissolution in a 1-M HNO sub(3) solution with heating and re-precipitation upon addition of H sub(2)O sub(2) to the solution. Finally, an environmentally friendly and economical process to recover pure uranium from contaminated (U,Gd)O sub(2) scraps was suggested.