[1I04-07] Vitrification 2

[1I07] Effect of metal-supported catalyst on the hydrothermal decomposition of solvent degradation products in reprocessing process

*Mayu Shimosawa¹, Tatsuya Horimai², Kiyoshi Anzai², Norio Kanehira², Tetsuo Honma¹ (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 PUREX process can be degradated by radiolysis into dibutyl phosphate (DBP). The spent extracted solvent has been recycled with aqueous carbonate solution to produce alkaline liquid waste (ALW). ALW contained DBP has some risk for pipe blockage. In our previous study, hydrothermal DBP decomposition has been 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. Therefore, we performed hydrothermal DBP decomposition with metal supported catalysts to reduce reaction temperature. We also studied apparent first-order rate constant to elucidate an influence of catalyst species on DBP decomposition in hydrothermal condition.