@article{oai:repo.qst.go.jp:00084931,
 author = {Akihiro, Uehara and Daisuke, Akiyama and Ikeda-Ohno, Atsushi and Chiya, Numako and Yasuko, Terada and Kiyofumi, Nitta and Toshiaki, Ina and Shino, Takeda and Akira, Kirishima and Nobuaki, Sato and Akihiro, Uehara and Shino, Takeda},
 journal = {Journal of Nuclear Materials},
 month = {Nov},
 note = {Characterization of the fuel debris has been required for decommissioning Fukushima Daiichi Nuclear Power Station. To understand the reaction mechanisms involved for mixed UO 2 –ZrO 2 compounds, these materials were treated at high temperatures (1473 to 1873 K) under oxidizing, inert, and reducing atmo- spheres. The reaction products were analysed by a combination of powder X-ray diffraction (PXRD) and X-ray absorption spectroscopic measurements of the U L III - and Zr K-edges. Principal component analysis of the X-ray absorption near edge structure and extended X-ray absorption fine structure of U L III - and Zr K-edges provided a breakdown of the composition of each species within the products, these results were further supported by PXRD. Under an oxidizing atmosphere, the formation of U 3 O 8 and U 2 Zr 5 O 15 was observed in equilibrium with UO 2 , monoclinic-ZrO 2 , and tetragonal-ZrO 2 . However, when O 2 gas was purged through the reaction tube during the cooling process to room temperature, pentavalent U in ZrU 2 O 7 was produced by the oxidation of solid solution UO 2 formed at > 1774 K during the tempera- ture dropped at < 1473 K. Under the inert atmosphere, mixed oxides of uranium were found to form at > 1673 K due to a low concentration of O 2 impurity with the Ar gas. Although the oxidized UO 2 was able to form in such a system, tetravalent UO 2 and its solid solution were instead present throughout the whole temperature range examined under a reducing atmosphere (H 2 gas). This study can pave the way for understanding the interaction between the nuclear fuels and the cladding materials in damaged reactors enabling further simulation of possible decontamination procedures.},
 title = {Speciation on the reaction of uranium and zirconium oxides treated under oxidizing and reducing atmospheres},
 volume = {559},
 year = {2021}
}