Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (7): 70102-070102.doi: 10.11889/j.0253-3219.2018.hjs.41.070102


Study on the microstructure of Th1-xUxO2+y by synchrotron radiation XAFS technique

XIE Chunyu1,2, CAO Hanjie1,2, YUE Zenghui1,2, BAO Hongliang1, WANG Jianqiang1   

  1. 1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-03-17 Revised:2018-04-23 Online:2018-07-10 Published:2018-07-07
  • Supported by:
    Supported by National Natural Science Foundation of China (No.U1532259, No.21701183)

Abstract: [Background] Thorium-uranium mixed oxides exist in different stages of the thorium fuel cycle. The physicochemical properties of Th-U mixed oxides, such as melting point, solubility, and oxido-reduction, are closely related to their microstructures. [Purpose] This study aims to study the microstructure of the Th-U mixed oxides by X-ray absorption fine structure (XAFS) technique. In order to macroscopically simulate the physical and chemical properties of Th-U mixed oxides, relevant microstructure data are provided. [Methods] The local structures of Th and U in as-prepared Th1-xUxO2+y samples are obtained by XAFS spectroscopy technique. [Results] The Th and U L3-edge XAFS data shows that the dominant structure in Th1-xUxO2+y is the mixture of ThO2 component and local U3O8 component. The extended X-ray adsorption fine structure (EXAFS) data of Th0.8U0.2O2+y sample is further analyzed. The result shows that there is Th-U interaction in Th0.8U0.2O2+y sample. The Th-U interaction results that the Th-Th/U bond length in Th0.8U0.2O2+y slight shorter than that of pure ThO2 and the U-O bond length in Th0.8U0.2O2+y larger than that of pure U3O8. [Conclusion] The XAFS technique can supply complementary structure information of Th-U mixed oxides, such as the local structure of Th and U.

Key words: Synchrotron radiation, XAFS, Th-U mixed oxides, Microstructure

CLC Number: 

  • TL99