Rapid separation of zirconium using microvolume anion-exchange cartridge for ⁹³Zr determination with isotope dilution...

Estimating the risks associated with radiation from long-lived fission products (LLFP) in radioactive waste is essential to ensure the long-term safety of potential disposal sites. In this study, the amount of ⁹³Zr, a LLFP, was determined by ICP-MS after separating Zr from a spent nuclear fuel solution using a microvolume anion-exchange cartridge (TEDA cartridge). Zirconium in 9.4 M HCl was stably retained on the TEDA cartridge and readily eluted with 0.75 mL of a mixed solution of 9.4 M HCl and 0.01 M HF. The time taken to complete the Zr separation was 1.2 min. Almost all the other elements initially present in the spent nuclear fuel sample were removed, leading to accurate measurement of all six Zr isotopes (⁹⁰Zr, ⁹¹Zr, ⁹²Zr, ⁹³Zr, ⁹⁴Zr, and ⁹⁶Zr). This demonstrated that the TEDA cartridge allowed highly selective separation of Zr regardless of its small bed volume of 0.08 cm³. The concentrations of these isotopes were determined by an isotope-dilution method using a natural Zr standard that has a different isotopic composition from that of the spent nuclear fuel sample. The amount of ⁹³Zr in an initial spent nuclear fuel pellet was 1081 ± 79 ng per mg of ²³⁸U. The measured concentrations of all Zr isotopes, as well as the isotopic composition, were consistent with values predicted using a burnup calculation code.