Evaluation of Aluminum Hexacyanoferrate utilization for PGM and Mo removal from simulated high-level-raffinates in reprocessing for repository area minimization

Nakase, Masahiko*; Mishima, Ria ; Abe, Takumi ; Okamura, Tomohiro*; Asano, Hidekazu*

Higher burnup LWR and MOX spent fuels contain increased levels of Platinum Group Metals (PGMs; Pd, Ru, Rh) and Mo, necessitating their control to ensure stable glass melter operations and prevent yellow phase formation, thereby maintaining vitrified glass quality. Separating PGMs and Mo during reprocessing can significantly reduce the repository space required for vitrified high-level wastes. This study explores the use of Aluminum Hexacyanoferrate (AlHCF) for simultaneous separation of PGMs and Mo, which involves the elution of structural Al during sorption. A fundamental methodology was developed for analyzing the back-end processes of the nuclear fuel cycle, focusing on the quantitative impact of AlHCF. By integrating adsorption experiments of simulated high-level liquid waste with mass balance calculations and thermal conductive calculation via NMB 4.0, the study identified practical AlHCF utilization conditions (11 to 40 wt% waste loading and 100 to 200 kg/tHM of AlHCF). It also established the relationship between AlHCF amount, waste loading, and reductions in both vitrified waste and repository size, highlighting optimal conditions for minimizing repository footprint.