Optimization of a radiochemical-gravimetric workflow for Ni recovery in complex radioactive waste matrices prior to 59Ni and 63Ni determination

Radiochemical analysis of radioactive waste containing difficult-to-measure radionuclides such as 59 Ni and 63 Ni requires robust separation and recovery strategies. In this study, a radiochemical-gravimetric workflow for quantitative nickel recovery was systematically optimized using real radioactive waste samples. Critical operational parameters were evaluated to minimize Ni losses and improve recovery. The optimized workflow, based on AG 1-X4 anion exchange resin, Ni Resin packed in in-house prepared glass columns, and polyethersulfone membrane filtration, achieved recoveries of (89 ± 9) % by gravimetry and (88 ± 10) % by ICP-OES. The methods showed no statistically significant difference ( p = 0.384) and exhibited a significant positive correlation (r = 0.77), supporting reliable subsequent 59 Ni and 63 Ni determination in complex radioactive waste matrices.