Innovative separation method for advanced spent fuel reprocessing based on tertiary pyridine resin

Radiochemical separation experiments have been performed in order to realize a novel reprocessing method based on chromatography techniques using a novel pyridine resin. The newly synthesized tertiary pyridine resin with two functions of ion exchanger and soft-donor was dedicated to the experiments, where highly irradiated mixed oxide fuel from the experimental fast reactor JOYO was used as a reference spent fuel. With a 3-step separation, pure Am and Cm were individually obtained as minor actinide products, and ¹⁰⁶Ru group, lanthanides with ¹³⁷Cs group and Pu group were fractionated, respectively. The decontamination factor of ¹³⁷Cs and trivalent lanthanides (¹⁵⁵Eu, ¹⁴⁴Ce) against the Am product exceeded 3.9 × 10⁴ and 1.0 × 10⁵, respectively. The decontamination factor as the mutual separation of ²⁴³Cm was larger than 2.2 × 10³ against the Am product. Moreover, the content of ¹³⁷Cs, trivalent lanthanides and ²⁴³Cm in Am product did not exceed 2 ppm. The tertiary pyridine resin method is a candidate separation system for an “advanced ORIENT process”, where enhanced separation, transmutation and utilization of actinides, long-lived fission products and rare metal fission product would be oriented.