Structural analysis of molybdenum in the nuclear waste vitrification process

Okamoto, Yoshihiro; Nagai, Takayuki; Tanida, Hajime; Sato, Seiichi*; Inose, Takehiko*; Hatakeyama, Kiyoshi*; Akiyama, Daisuke*; Koshino, Haruya*; Kirishima, Akira*

no journal, , 

To understand the behavior of molybdate compounds (yellow phase; YP) that reduce the safety performance of vitrified products, the local structure and chemical state of molybdenum in the process where the vitrified radioactive waste is produced was investigated using simulated waste samples and XAFS analytical technique. It was found that sodium molybdate was generated when only the simulated high-level liquid waste (HLLW) was heated, while molybdenum dissolved into the glass phase when heated together with the borosilicate glass. This indicates that sodium molybdate tends to form when the molybdenum has little contact with the glass. Micro XAFS analysis using an X-ray beam focused on 1 micro meter showed that the YP contained more calcium molybdate, not sodium molybdate.