[1D12-16] Aqueous Reprocessing and Pyroprocessing

[1D14] Effect of solid catalyst on the hydrothermal decomposition of solvent degradation products from reprocessing process.

*Tetsuo Honma¹, Mayu Shimosawa¹, Tatsuya Horimai², Kiyoshi Anzai², Takeshi Tsukada² (1. NIT Hachinohe College, 2. JNFL)

Keywords:high-pressure and high-temperature water, Alkaline liquid waste, Solvent degradation products, Dibutyl phosphate, Solid catalyst

Tributyl phosphate as a extraction solvent for PULEX process can be converted by radiolysis into dibutyl phosphate (DBP). The spent extracted solvent has been recycled by washing with aqueous carbonate solution. DBP in alkaline liquid waste produced by washing process has some risk for pipe blockage. DBP decomposition in hydrothermal condition can be achieved 99% conversion with 30 min at 573 K and 5 min at 623 K. However, sodium carbonate precipitation has been occurred above 573 K. In this study, we have performed hydrothermal DBP decompositions with metal oxide catalysts to reduce reaction temperature and to avoid carbonate precipitations in hydrothermal conditions. A first-order reaction analysis and product qualification analysis by mass spectroscopy has been also performed.