[2B17-20] Aqueous reprocessing

5:55 PM - 6:10 PM JST(8:55 AM - 9:10 AM UTC)

[2B20] Study on the structural changes of HONTA in organic phase due to neodymium (Ⅲ) ion extraction

*Hiroto Saito¹, Hiroki Fukumoto¹, Yasunori Miyazaki², Yuichi Sano² (1. Ibaraki Univ., 2. JAEA)

Keywords:

solvent extraction,HONTA,minor actinide

High-level liquid waste from spent fuel reprocessing is vitrified and disposed of as high-level radioactive waste (HLW). To address the growing challenge of repository capacity, separating minor actinides (MA: Am, Cm) from HLW is expected to reduce the number of HLW canisters per unit area, decreasing the required disposal space. SELECT process using CHNO-type extractants has been proposed for MA separation. This study focuses on the elemental selectivity of N,N,N’,N’,N’’,N’’-hexaoctylnitrilotriacetamide (HONTA) toward Nd ion as pseudo MA. Shaking extraction experiments of HONTA/n-dodecane were conducted with nitric acid concentration as a parameter, and a complex formation model was developed based on the extraction behavior of water, nitric acid and Nd. Structural analyses including ¹H NMR revealed that nitric acid co-extraction affects Nd selectivity and third-phase formation.