Accurate measurement of 55Fe in radioactive waste

A radiochemical method was developed for the accurate 55Fe determination in various radioactive waste, in particular samples contaminated with 241Pu. It consisted of three purification steps based on first ammonium hydroxide precipitation, and then anion exchange separation followed by TRU®-based extraction chromatography. It was characterized by an iron recovery yield of about 80% for all the studied samples and a 60Co decontamination factor of 106. In comparison to a standard protocol based on iron cupferrate extraction in chloroform, an improvement of a 30-fold factor was achieved towards plutonium. The developed TRU®-based procedure was validated by participating in interlaboratory exercises.